Blackberries

Last updated on March 8, 2024

Growing blackberries

Blackberries

 

New plantings:  Spacing

There is considerable variation in spacing. Table 1 lists the commonly used distance and number of plants required.

Table 1. Blackberry plant spacing and number of plants required
Distance between plants (meters) Distance between rows (meters) Number of plants required (hectare) Number of plants required (acre)
1.8 (6 ft) 3.6 (12 ft) 1,540 605
2.4 (8 ft) 2.4 (8 ft) 1,680 680
2.4 (8 ft) 2.7 (9 ft) 1,483 600
2.7 (9 ft) 2.7 (9 ft) 1,329 538
2.7 (9 ft) 3.0 (10 ft) 1,196 484
 

Varieties

There are many blackberry varieties available, some of which are thorny while others are thornless.

They vary widely in such features as:

  • Berry size
  • Flavour
  • Harvest season
  • Hardiness
  • Productivity
  • Susceptibility to diseases

Chester Thornless

The most widely planted fresh market variety in the world. Fruit is shiny, black and of good quality. Plants are vigorous and need to be planted at a wider spacing than Loch Ness. Laterals need to be pinched regularly. It is generally too late maturing for reliable production in B.C. unless covers are used to provide protection from fall rains.

Loch Ness

This is currently the standard semi-erect thornless blackberry for fresh sales in the Fraser Valley and Vancouver Island. It may not be reliably hardy for Interior locations. The fruit is large, relatively firm with good flavour and shelf life. It has a long harvest season (late July to early September). The plants are moderately winter hardy and vigorous, but susceptible to crown gall.

Metolius

A very early, trailing, thorny variety from the USDA-ARS, Oregon. Suitable for the fresh market. Good yields of firm, uniform shape fruit. Good flavour. Firm, tough skin should result in good shelf life. Vigorous plant with stiff laterals.

Obsidian

A very early, trailing, thorny variety from the USDA-ARS, Oregon. Suitable for the fresh market. Very high yields of large, firm, excellent flavour fruit. Maintains black colour after harvest. Has demonstrated good winter hardiness in the Fraser Valley.

Triple Crown

A semi-erect thornless blackberry for fresh market production. Ripens later than Loch Ness. Excellent yield potential. Flavour is superior to Loch Ness. Fruit is large and excellent quality, but is slightly softer than Loch Ness and may not be suitable for shipping.

Black Diamond (Trial)

A new thornless, trailing blackberry from the USDA-ARS, Oregon. Adapted to the processing market, but also suitable for the local fresh sales. Fruit are firm, medium-sized, uniform with good traditional blackberry flavour, Yield potential is high. It is less vigorous than other trailing types and should be planted closer within the row.

Onyx (Trial)

A new, late season trailing thorny blackberry from the USDA-ARS, Oregon. Suited for the fresh market. High yields of firm, sweet, conic fruit that ship well.

Ouachita (Trial)

A new, thornless, erect blackberry from the University of Arkansas. Suitable for the fresh market. Fruit are very firm, medium size with good flavour. Yield potential is high.

Blackberry hybrids

There are a number of trailing berries that were derived from crosses between blackberries and red raspberries. The most common commercially available varieties are Boysen, Logan and Tayberry.

 

Cover crops

Annual or permanent cover crops can be planted between the blackberry rows.

Cover crops can:

  • Improve soil structure and drainage
  • Improve trafficability
  • Suppress weeds
  • Take up excess nitrogen left in the soil in the Fall

Annual cover crops

These are planted every year after harvest and before September 15. Barley and oats are preferred as they grow rapidly in early fall but are usually killed by colder winter temperatures.

In the spring, cover crop residue can be flail mowed along with prunings or rotovated into the soil surface.

Nitrogen from the decaying cover crop is then released into the soil for use by the raspberry crop. Fall or cereal rye, or annual grasses, can also be used. They are less effective at trapping leachable nitrogen in the fall or winter as their main growth period is in the spring. These cover crops may require additional management in the Spring, such as mowing, discing, or herbicide application, to prevent them from competing for nutrients and water.

Perennial cover crops

Fescue can be used as a permanent cover crop in blackberries but must be managed to prevent it from growing into the blackberry row.

Permanent cover crops prevent weed growth, compaction and soil erosion, however, they are difficult to repair if ruts form from driving on them when the soil is too wet.

 

Nutrient management

Soil and leaf analysis

As a general recommendation, blackberry growers should follow the same soil and plant tissue testing info provided for raspberries. No calibrated soil or tissue testing system is available for blackberries. For more information, please consult the Berry Production Guide: Nutrient Management (PDF).

Soil analysis is the most accurate guide to fertilizer requirements for blackberries.

Sampling method

Take soil samples from each sampling location in the field: Site (1): at the centre of the fertilizer and between the plants along the crop row, and Site (2): at the center of the cultivation/root mound between plants in the crop row (see figure below). Take samples from 10 to 20 different locations for each 8 hectare (20 acre) field area. Mix all the samples together.

Avoid areas in the field that are not typical such as low spots or gravel outcrops. Where fields have more than one soil type, the areas should be sampled separately. Take soil samples for nitrogen analysis from the 0 to 30 cm (0 to 1 ft) of soil. Take soil samples for all other nutrients from 0 to15 cm (0 to 6 in).

Diagram of soil sampling

Sampling time

For mature crops, take soil samples for nitrogen after crop harvest, or between August 15 and September 15. A spring soil test cannot be used to assess nitrogen fertility levels of a blackberry field. For all other nutrients, fall or spring soil sampling can be used.

Leaf analysis

Leaf analysis can be used to determine nutrient needs in blackberries but it has not been well-tested in B.C. Leaf analysis can also be used if a nutrient deficiency is suspected. Take leaf samples from mid-July to early-August to determine the fertilizer requirements for the following year.

For the best interpretation, take leaf samples at the same stage of plant development (e.g. mid-harvest or late-harvest) each year and monitor year-to-year trends in nutrient status. Collect the most recently fully expanded leaves from the new primocanes, about 30 cm from the tip of the cane. Leaves must be free of soil, pesticide and irrigation water residue. Select about 10 leaves from each of 5 plants distributed at random throughout the field.

When checking for suspected nutrient deficiencies, take separate samples from good and poor growth areas and compare the results. These samples can be taken at any time during the growing season. Air dry all samples in an open paper bag or take them directly to a laboratory.

Suggested range of leaf nutrient levels for blackberries based on late July to early August leaf analysis
Element Low Adequate High
Phosphorus (P)% < 0.16 0.16 to 0.18 0.19+
Potassium (K)% < 1.0 1.0 to 1.25 2.0+
Boron (B) ppm < 25.0 25 to 30 30.0+

Source: OSU EM 8903-E Nutrient Management Guide - Caneberries (2006)

Fertilizers

New plantings

In most instances no fertilizer is required at planting. Once growth begins, band a complete fertilizer 30 cm (1 ft) from the transplant. Recommended rates of nutrients are given below for new and established plantings.

Established plantings

In the second and subsequent years of growth blackberries have a low requirement for most nutrients. Usually nitrogen is the only nutrient required. Apply the nitrogen in a 1 m (3 ft) band around the plants or band half the rate down either side of the row about 40 cm (16 in) from the plant. Apply nitrogen when growth begins.

Macro-nutrient application rates for blackberries
Nutrient New plantings Established plantings
Nitrogen (N) 15 - 50 kg/ha
(6 - 20 kg/acre)
55 - 95 kg/ha
(22 - 38 kg/acre)
Phosphorus (P2O5) 15 - 90 kg/ha
(6-36 kg/acre)
0 - 45 kg/ha
(0 - 18 kg/acre)
Potassium (K2O) 15 - 115 kg/ha
(6 - 47 kg/acre)
0 - 55 kg/ha
(0 - 22 kg/acre)

Application rates are dependent on spacing of plants. The highest application rates are set for plant spacings that give about 1600 plants per hectare.

Manure use

Poultry manure is an effective source of nitrogen for blackberries but must be stored and spread in an environmentally responsible manner. A manure spreader designed for side delivery or band application can be used to apply poultry manure. Spread manure only once each season – broadcast and incorporated into the soil in the early Spring, after February 15 and before April 15.

Base application rates on a late summer soil test. Most poultry manure contains up to 12 kg/yd3 of total nitrogen. Some ammonia nitrogen is lost during application and losses are greater when manure is left on the soil surface for more than 12 hours.

Poultry manure is generally very high in calcium and contains high levels of ammonia nitrogen that is readily available to plants.

Pre-plant application

Apply manure at a rate that does not exceed 50 kg/ha (20 kg/acre) of available nitrogen. Newly planted blackberries require low amounts of nitrogen and this rate is almost the maximum required. Applying and immediately incorporating about 5 yd3/ha (2 yd3/acre) poultry manure provides most of the nitrogen required by newly planted blackberries.

Established plantings

Apply manure at a rate that does not exceed 90 kg/ha (36 kg/acre) of available nitrogen. Established blackberries require low amounts of nitrogen and this rate is almost the maximum required.

Applying and immediately incorporating about 17 yd3/ha (7 yd3/acre) poultry manure provides most of the nitrogen required by established blackberries.

A soil test about three (3) weeks after applying manure will show if more additional nitrogen is required.

 

Pruning/training

Remove floricanes at the crown once they have fruited. Training of new shoots to the wires is best done in the late Winter or early Spring to avoid winter injury.

Head back new canes to the desired length when they are tied to the wires.

A plant should produce 10 to 14 healthy canes each year. If laterals are sent out, remove them entirely or cut them back to five or six buds.

 

Pollination

Consult the Berry Production Guide: Pollination (PDF) for more information.

 

Blackberry weed management

Prior to planting, it is critical to control existing perennial weeds and brush. Use of glyphosate formulations such as Roundup or Touchdown effectively control tough weeds without creating a soil residue concern.

Note: Herbicide application rates are listed on pesticide labels and in the production guide for broadcast or total field coverage. If spraying a band over the row area only, then the treated area is only a portion of the whole field and rates must be reduced accordingly. For example, when spraying 1 m bands on rows 3 m apart, only one third of the field is treated.

 

Year of planting

Year of planting: herbicide application rates
Stage Product Rate Comments
Prior to weed emergence Devrinol 50DF (50% napropamide) 9 kg/ha (3.6 kg/acre)
  • Apply after planting but prior to weed emergence. If rainfall does not occur within 7 days for a spring or fall application or 2 days for a summer application, irrigate with sufficient water to wet the soil to a depth of 5 to 10 cm.
  • Apply in enough water to get even distribution over the soil surface. This is usually accomplished in the range of 200 to 900 L/ha of water.
Prior to weed emergence Devrinol 10G (10% napropamide) 45 kg/ha (18 kg/acre)
  • Apply in the fall through early spring prior to weed emergence.
  • Requires mechanical incorporation, adequate irrigation or natural moisture for optimum results. The treatment must reach the zone of weed seed germination.
  • If rainfall does not occur within 7 days for a spring or fall application or 2 days for a summer application, a shallow incorporation to a depth of 2.5 to 5 cm or irrigation with sufficient water to wet the soil to a depth of 5 to 10 cm is necessary.
Prior to weed emergence Dual II Magnum (915 g/L S-Metolachlor) 1.15 – 1.75 L/ha (0.46 to 0.7 L/acre)
  • Apply to the soil in the early spring.
  • The lower rate is suggested on newer plantings as young plants may be more sensitive to injury.
  • Lower rates should be used on soils that are relatively coarse textured and the higher rates on fine textured soils.
  • Apply in a minimum of 150L/ha (60) of water.
  • Maximum one application per year.

 

 

Established plantings

Established plantings: herbicide application rates
Stage Product Rate Comments
Prior to weed emergence Devrinol 50DF (50% napropamide) 9 kg/ha (3.6 kg/acre)
  • Apply after planting but prior to weed emergence. If rainfall does not occur within 7 days for a spring or fall application or 2 days for a summer application, irrigate with sufficient water to wet the soil to a depth of 5 to 10 cm.
  • Apply in enough water to get even distribution over the soil surface. This is usually accomplished in the range of 200 to 900 L/ha of water.
Prior to weed emergence Devrinol 10G (10% napropamide) 45 kg/ha (18 kg/acre)
  • Apply in the fall through early spring prior to weed emergence.
  • Requires mechanical incorporation, adequate irrigation or natural moisture for optimum results. The treatment must reach the zone of weed seed germination.
  • If rainfall does not occur within 7 days for a spring or fall application or 2 days for a summer application, a shallow incorporation to a depth of 2.5 to 5 cm or irrigation with sufficient water to wet the soil to a depth of 5 to 10 cm is necessary.
Prior to weed emergence Authority (480g/L sulfentrazone) 0.29 L/ha (0.12 L/acre)
  • Apply as a broadcast spray or as a uniform band directed at the base of canes. Do not allow spray to come in contact with crop. Apply a single spray in a minimum water volume of 100L/ha (40L/acre). At least 0.5 cm of rainfall or irrigation is necessary to activate the herbicide. Do not apply within 3 days of harvest
Prior to weed emergence Dual II Magnum (915 g/L S-Metolachlor) 1.15 – 1.75 L/ha (0.46 to 0.7 L/acre)
  • Apply to the soil in the early spring as a banded application to both sides of the plant row prior to weed emergence.
  • Avoid contact with foliage.
  • Test on a few plants of each cultivar before widespread. application to ensure no cultivar-specific phytotoxicity.
  • The lower rate is suggested on newer plantings as young plants may be more sensitive to injury.
  • Lower rates should be used on soils that are relatively coarse textured and the higher rates on fine textured soils.
  • Apply in a minimum of 150L/ha (60) of water.
  • Do not apply within 28 days of harvest.
Prior to weed emergence Princep Nine-T (90% simazine) 2.5 to 3.75 kg/ha (1 to 1.5 kg/acre)
  • Apply in early spring as a directed spray in a minimum of 300 L/ha of water in plantings established at least one year. Do not spray young shoots. Requires surface moisture for activation. Loss of activity and poor weed control may result under prolonged, dry conditions. Not effective on established weeds.
Prior to weed emergence Sandea (72.6% halosulfuron, present as methyl ester) 35 to 70 g/ha (14 to 28 g/acre)
  • Apply in a minimum of 140 L/ha (56 L/acre) of water.
  • Apply as a broadcast directed application to the ground on each side of the row.
  • Avoid contact with canberries.
  • If small weeds are present, tank mix with a post-emergence broad spectrum-type herbicide to enhance the spectrum of weed control.
  • This product will have reduced or no residual activity if ground cover prevents contact with the soil.
  • Soil moisture is needed for optimum pre-emergent weed control.
  • Do not apply to plants less than 2 years old or plants under stress.
  • Do not apply more than 140 g of Sandea per 12 month period.
  • Do not apply within 14 days of harvest.
After weeds emerge Prism SG (25 % rimsulfuron) 60 g/ha (24 g/acre)
  • Apply a directed, early postemergence spray to actively growing weeds.
  • Minimize contact with blackberry plants.
  • Use on crops that have gone through at least one growing season and are in good health and vigour
  • Use a non-ionic surfactant such as Cittowett Plus, Agral 90 or Ag-Surf at 2 L/1000 L of spray mix.
  • When applied as a banded treatment, Prism may be applied twice per year.
  • Do not apply within 21 days of harvest.
Annual weeds (between the rows only) Aim EC (240 g/L carfentrazone-ethyl) 37 to 117 mL/ha (15 to 47 mL/acre)
  • Apply between the rows with a hooded sprayer to emerged weeds. Crop injury will occur if drift is allowed to come in contact with green stem tissue, leaves, blooms or fruit.
  • To improve control, apply with surfactants such as Agral 90 or Ag-Surf at 0.25% (0.25 L/100 L of water) or Merge at 1% (1 L/100 L of water).
  • Do not apply within 15 days of harvest.
Annual grasses and broadleaf weeds Alion (200 g/L indaziflam) 375 mL/ha (150 mL/acre)
  • Apply as directed spray to the soil either under dormant canes prior to bud break and new cane emergence, or after mowing but prior to new cane emergence.
  • Only use in plantings established for at least one year and exhibiting normal growth and good vigour.
  • Do not apply prior to any soil disturbance.
  • Apply a maximum of one application per season.
  • Do not apply within 14 days of harvest.
Annual grasses and broadleaf weeds AXXE (36% Ammonium Salt of Fatty Acid  45 to 106 L/ha (18 to 42 L/acre) 
  • Adjust rate and water volume depending on height of weeds as specified on label.
  • Use as a shielded spray application and do not allow spray to contact the crop.
  • Do not apply within 2 hours of rainfall or irrigation.
  • Can also be applied prior to weed emergence.
Annual grasses and broadleaf weeds Beloukha (500 g/L Pelargonic acid) 16 to 27 L/ha (6.4 to 10.8 L/acre)
  • Apply in 200 to 300 L/ha (80 to 120 L/acre) of water.
  • Apply when weeds are less than 10 cm tall.
  • For best results, apply at temperatures above 15â—¦C and low humidity.
  • Use the minimum effective rate for weed control. For hard to control weeds higher rates or repeat applications may be required.
  • Use a shielded spray to avoid damage to the crop.
  • Use in fields that are older than 2 years where that have become hardened or woody.
  • Do not make more than 4 applications per season.
  • Make subsequent applications on a 7-14 day interval.
  • Do not apply within 24 hours of harvest.
After weeds emerge, broadleaf weeds

Eragon LQ (342 g/L saflufenacil)

73 mL/ha (29 mL/ac)
  • Apply as a banded application directed to the base of canes prior to the plants breaking winter dormancy.
  • Add Merge adjuvant at a rate of 1 L/ha (0.4 L/ac).
  • Apply in a minimum of 100 L/ha (40L/acre) of water.
  • One application per season.
  • Do not allow spray drift to contact dormant canes.
After weeds emerge, annual weeds and suppression of some perennial weeds Serene Liquid Herbicide (20% acetic acid) variable dilution rates, refer to label
  • Controls ragweed species, chickweed, lamb's-quarters, black medic, and seedling Canada fleabane. 
  • Apply under sunny conditions when temperatures are above 21â—¦C.
  • Apply as a uniform band or spot application directed at weeds on the ground between the crop.
  • Apply using hooded or shielded application equipment.
  • Ensure spray drift will not come in contact with foliage.
  • Do not apply when plants are under stress.
  • Retreatment is required for regrowth of weeds.
After weeds emerge, broadleaf weeds and nutsedge Sandea (72.6% halosulfuron, present as methyl ester) 35 to 70 g/ha (14 to 28 g/acre)
  • Apply in a minimum of 140 L/ha (56 L/acre) of water.
  • For control of nutsedge, use a minimum of 52.5 g/ha and apply when nutsedge plants are at the 3-5 leaf stage.
  • Apply as a broadcast directed application to the ground on each side of the row.
  • Avoid contact with canberries.
  • If small weeds are present, tank mix with a post-emergence broad spectrum-type herbicide to enhance the spectrum of weed control.
  • Do not apply to plants less than 2 years old or plants under stress.
  • Do not apply more than 140 g of Sandea per 12 month period.
  • Do not apply within 14 days of harvest.

 

 

Blackberry insect and mite management

Most insecticides are hazardous to bees. Avoid applying insecticides during the blossom period. Should it be necessary to apply insecticides during this period, notify beekeepers in the area. Evening applications are safer to bees than daytime applications. 

 

Aphids

Hosts

Attacks red raspberry, loganberry, and blackberry. 

Damage

Aphids rarely do any direct damage to blackberries. 

Identification

Aphids are found in colonies on new shoot growth, buds, undersides of leaves, and near flower and fruit clusters. Adult aphids are small (2 to 3 mm) and vary in colour from pale yellow, green, to red.

As colonies become crowded, winged forms appear. The immature stages resemble small wingless adults. 

Life history

Aphids overwinter as eggs on plants. Under coastal conditions eggs hatch about May. The nymphs feed on blossoms, then growing shoots and leaves. There are several generations during the Spring and Summer. In the Fall, winged forms disperse and lay eggs on the overwintering host plants. 

Monitoring

Early detection is important for effective, economical control. Inspect growing tips weekly from before bloom to harvest. Inspect several sites, especially in the upwind margins of the planting where wind-blown aphids are most likely to occur.

Management

Biological control

Aphids are often controlled by a number of native predators and parasites including ladybugs, lacewings, and syrphid larvae. If chemicals are needed for other pests, pesticides that will have the least impact on the beneficial insects should be used. Refer to “Pesticide toxicity to beneficial insects” in the General Pest Chapter.

Chemical control

Admire 240F or Alias 240SC (240 g/L imidacloprid) at 175 mL/ha (70 mL/acre) as a foliar spray in enough water to obtain good coverage. Apply post-bloom. Do not apply immediately pre-bloom or during bloom when bees are actively foraging. Do not apply more than 3 times per season. If multiple applications are necessary, allow at least 7 days between sprays. Do not apply within four days of harvest. Note:  Admire can no longer be used.

Note:  As of April 11, 2021, all Admire and Alias (imidacloprid) labels will be updated to reflect new requirements.  If these products are applied post-bloom in berry fields, cutting back of all woody growth must occur after harvest and before the next season’s bloom (i.e., stumping the plants to the ground).  

Movento 240SC (240 g/L spirotetramat) at 220-365 mL/ha (88-146 mL/ac) in a minimum of 300 L/ha (120 L/ac) of water.  Apply post-bloom.  Do not apply more than once every seven days.  Do not apply more than three times per season. Do not apply within three days of harvest; or

Sivanto Prime (200g/L flupyradifurone) at 500-750 ml/ha (196-295 ml/acre) in a minimum of 100 L/ha (40 L/acre) of water as a directed foliar spray. Do not apply more than once every seven days. Do not exceed 2000 ml/ha (787 ml/acre) per season. Do not apply within 0 days of harvest.

*PHI = Pre-harvest interval  

 

Cane maggot

Hosts

All cane fruits

Damage

Cane maggots cause sporadic injury but are seldom a serious pest. In early spring maggots bore about 15 cm down into the canes, then turn outward and girdle them, leaving a bluish ring. The shoot droops at this point, then shrivels and dries up.

Identification

The adult is a small fly that is rarely noticed. The maggot is creamy white and reaches about 0.5 cm in length.

Life cycle

There is one generation a year. In early spring the adult fly lays a single egg on unopened leaves at the tip of a new shoot. This egg hatches within a week and the resulting maggot bores down inside the shoot.

The maggot remains in the shoot until next Spring, when it becomes an adult fly.

Monitoring

Wilted shoots are the only reliable indication of this pest.

Management

Cultural control

Cut off any wilting canes at ground level and destroy them.

Chemical control

This insect is seldom destructive enough to justify applying sprays

 

 

Crown borer

Hosts

All cane fruits, particularly raspberry and loganberry.

Damage

Larvae girdle new canes, causing galls at the base. These weakened canes often break off when the plants are handled. Large larvae tunnel in the fleshy part of the root, further reducing the vigour of the canes.

Identification

The day-flying adult is a clear winged moth closely resembling a yellow-jacket wasp in colour and size. The larvae are white with brown heads and are found in tunnels inside the cane or root.

Life history

This insect has a two-year life cycle. The eggs are laid in August and September on the undersides of leaves. The young larvae crawl down the canes and spend the first winter in a cell on the cane just under the soil. The next spring they bore into the base of the cane and cause swellings at or below the soil surface. They spend the second winter in their tunnels, feed from spring until July when they become pupae and then adults.

Monitoring

Watch for canes that break off in the Spring. If more than 5% of the plants have hollow canes, chemical controls are recommended.

Management

Cultural control

Immediately after harvest or when setting canes on the wires, prune out loose canes and those with galls at the base. Cut back close to the crown.

Chemical control

If 5% or more of the crowns show damage, consider chemical treatment.

Altacor (35% chlorantraniliprole) at 215 to 285 g/ha (86 to 114 g/acre) as a basal spray in enough water to ensure good coverage of primocanes. Apply in late summer or early fall to first-instar larvae when they are actively feeding in the cambium, before they tunnel into the crown or canes. Use the high rate when pest pressure is heavy. Do not apply more than three times per season. Do not apply more than once every 14 days. Do not apply within 3 days of harvest.

 

 

European blackberry leaf midge (Dasineura plicatrix)

Hosts

Blackberry, raspberry, and loganberry.

Damage

Unopened leaves on primocanes and fruiting laterals turn black and fail to open or become distorted, twisted, kinked, or creased as they attempt to expand.

Identification

Small, milky coloured legless larvae, 1 mm wide and 2-3 mm long, are found within unopened leaves. Several can be present in an infested bud. Adults are small delicate flies which are rarely seen.

Life cycle

Adults emerge in the spring and lay eggs in unopened leaves. Larvae feed within the growing tips for about four weeks, and then drop to the soil to pupate. New adults emerge and lay eggs. There appears to be approximately three overlapping generations per year in south western BC. Larvae can be observed from mid May through late August. In late summer larvae drop to the soil and overwinter as mature larvae or pupae.

Monitoring

Look for damage on growing tips of primocanes and fruiting laterals in early May and through the summer. Damage on opening leaves can be seen all season, and tends to build up and spread through the field with each successive generation.

Management

It is not likely that this pest will reach levels high enough to affect yield as leaf midge is considered a minor pest in Europe. However, it is relatively new to B.C., and may have differing impacts on crops here. If midge is present in fields it should be monitored each year to determine if population and subsequent damage is increasing.

Cultural control

There are no known naturally occurring biological control agents for leaf midge.

Chemical control

There are no chemicals specifically registered for midge, however, broad-spectrum insecticides used for raspberry fruit worm, leafhoppers or leafrollers may give some control of leaf midge. Midges are generally difficult to control with pesticides because the larvae are protected by leaves and the generations are overlapping.

 

Fruitworm beetle

Hosts

Raspberry, loganberry and blackberry.

Damage

The adult beetles cause some yield reduction by feeding on unfolding leaves and blossom clusters. The larvae are a contamination problem when they burrow between the core and flesh of the berries.

Identification

The small (2-3 mm) yellowish brown beetles are somewhat flattened and covered with short hairs. Larvae are white, 3-4 mm long, and have short legs.

Life history

Adult beetles overwinter in the soil, emerging from late April to early May. They feed on the new leaves, blossoms and berries, and lay eggs on or near blossom clusters and green berries. These hatch into yellowish white larvae which enter the blossoms and young berries, some feeding until harvest.

Most larvae mature, leave the berry and drop to the ground where they enter the soil and pupate. Adults form in late summer and overwinter.

Monitoring

Reliable early detection techniques are not available for this pest.

Management

Chemical control

No products registered.

 

Leafrollers

Hosts

Cane fruits, strawberries, and many other plants.

Damage

The caterpillars (larvae) web and feed on terminal leaves and bore into ripening berries. During picking, these larvae may remain in the berries or drop from the bushes into the picking trays, contaminating the processed fruit.

The larvae may persist throughout the season unless controlled in the Spring.

Identification

Caterpillars are yellowish to green with light brown heads about 13 mm long when mature. The moths are buff with a wingspread of 13 to 19 mm.

Life history

There are several overlapping generations each year so that all stages may be found at the same time during the summer. Caterpillars overwinter in various sizes. They begin to feed as early as March.

Monitoring

Watch for webbed leaves and feeding damage on new growth in the early spring. Inspect crop thoroughly, especially on the outside edges where infestations are most likely to occur.

Management

Chemical control

If substantial numbers of early season caterpillars are detected, use one of the following. Do not apply during the blossom period.

Delegate WG (25% spinetoram) at 100 to 200 g/ha (40 to 80 g/acre) at egg hatch or to small larvae. Use the higher rate for high populations and/or larger larvae. Reapply if necessary. Delegate is toxic to bees. Do not apply when bees are actively foraging. Do not apply more than three times per year. Allow a re-treatment interval of at least 5 days. Do not apply within 1 day of harvest; or

Intrepid 240F (240 g/L methoxyfenozide) at 0.5 to 0.75 L/ha (0.2 to 0.3 L/acre). Monitor and time applications for egg hatch or when larvae are small. Use the higher rate under heavy insect pressure or when larvae are large. For leafrollers, apply before larvae roll up in leaves. Do not apply more than 3 times per year. Do not apply within 3 days of harvest; or

Harvanta (50 g/L cyclaniliprole) at 1200 to 1600 mL/ha (480-640 mL/acre) in a spray volume of 935 to 1400 L/ha (374-560 L/acre) of water. This product will provide suppression only. This product is toxic to bees - do not apply during the blossom period. Minimum re-treatment interval is 5 days. Do not apply more than two times consecutively within 30 days or more than two times within a single generation of the pest.  Do not apply more than 3 times per season or a maximum of 4.8 L/ha (1.92 L/acre). Do not apply within 1 day of harvest; or

Sevin XLR Plus (466 g/L carbaryl) at 5.25 L/ha (2.1 L/acre). Use in 1,000 to 2,000 L/ha of water. Do not apply during the blossom period or within 11 days of harvest; or

Sevin 50W (50% carbaryl) at 4.5 kg/500 L. Use 1,100 to 2,250 L/ha of water. Do not apply within 7 days of harvest; or

Success 480SC (480 g/L spinosad) at 145 to 182 mL/ha (58 to 73 mL/acre) in 300 to 500 L/ha of water. Use the upper rate under high insect pressure and/or on large larvae. Apply a maximum of 3 times per year and do not apply within 3 days of harvest; or

Entrust 80W (80% spinosad) at 80 to 109 g/ha (32 to 44 g/acre) or Entrust SC (240 g/L spinosad) at 267 to 364 mL/ha (107 to 146 mL/acre) in 300 to 500 L/ha of water. Use the upper rate under high insect pressure and/or on large larvae. Apply a maximum of 3 times per year and do not apply within 3 days of harvest. It is OMRI approved for organic production; or

DiPel 2XDF (Bacillus thuringiensis) at 525 to 1125 g/ha (210 to 450 g/acre) in 600 L/ha of water.

 

Leafhoppers

Damage

Leafhoppers are small, slender insects, varying in colour from pale white to brownish-green. Both nymphs and adults feed on the underside of the leaves sucking sap and causing whitish spots on the upper surfaces. Heavy infestations cause severe mottling, plant collapse and loss of yield. Leafhoppers over-winter as eggs under the bark and hatch in early May. A second generation appears in late July.

Management

The nymphs may persist throughout the season unless controlled in the spring.

Chemical control

Apply the first spray when blossom buds first separate and again again during the first week in August. If leafhoppers are present after harvest, apply another spray to prevent them from laying overwintering eggs under the bark of the canes.

Danitol (31% fenpropathrin) at 779-1169 ml/ha (312 to 468 ml/ac) in a minimum of 200L/ha (80 L/ac) of water.  Begin applications when first pest activity is noticed.  Do not make more than 2 applications per year. Rotate with non-pyrethroid products to delay development of resistance. Use a minimum re-treatment interval is 14 days. Do not apply within 15 days of harvest for hand harvested fields; or

Malathion 500 E (500 g/L malathion) at 1.25 to 2.0 L/1000 L water. Spray for thorough coverage. Repeat as necessary. Do not apply within 7 days of harvest; or

Malathion 85 E (85% malathion) at 610 to 975 mL/1000 L of water. Spray for thorough coverage. Repeat as necessary. Do not apply within 7 days of harvest; or

Note: Malathion is not effective unless temperatures are above 20°C. Do not apply malathion if bees are in the field.

Sevin XLR Plus (466 g/L carbaryl) at 5.25 L/ha (2.1 L/acre). Use in 1,000 to 2,000 L/ha of water. Do not apply during the blossom period or within 11 days of harvest; or

Sevin 50W (50% carbaryl) at 4.5 kg/500 L. Use 1100 to 2250 L/ha (440 to 900 L/acre) of water. Do not apply within 7 days of harvest; or

Admire 240F or Alias 240SC (240 g/L imidacloprid) at 175 mL/ha (70 mL/acre) as a foliar spray in enough water to obtain good coverage. Admire and Alias are toxic to bees. Do not apply immediately pre bloom or during bloom when bees are actively foraging. Do not apply more than 3 times per season. If multiple applications are necessary, allow at least 7 days between sprays. Do not apply within 4 days of harvest; or

Note:  As of April 11, 2021, all Admire and Alias (imidacloprid) labels will be updated to reflect new requirements.  If these products are applied post-bloom in berry fields, cutting back of all woody growth must occur after harvest and before the next season’s bloom (i.e. stumping the plants to the ground).

Assail 70WP (70% acetamiprid) at  56 to 86 g/ha (22 to 34 g/acre) in enough water to obtain good coverage. Use the higher rate when pest pressure is heavy.  Do not apply more than once every 7 days.  Do not apply more than 4 times per season. Do not apply within 1 day of harvest.

Note: Assail is toxic to bees. Do not apply during bloom when bees are actively foraging.

 

Sawflies

Adults are black, with yellow and reddish markings. Larvae are pale green caterpillars with white spines. They feed on the undersides and edges of leaves. They occur sporadically, seldom becoming a serious pest. For more information on this pest, refer to “Raspberries—Sawflies”.

Control

Sprays applied for leafhoppers (see above) will also control sawflies.

 

Spotted wing drosophila

Hosts

Berries, stone fruits and numerous wild hosts

Damage

Female flies lay eggs under the skin of ripe fruit. Larvae hatch and begin to feed within the fruit, causing softening in the area of feeding. There can be several larvae in a fruit, which hastens softening and fruit collapse. Holes the size of pin pricks are evident within the soft areas of infested blueberries.

Identification

Adults: 2-3 mm (1/8 inch) long, brownish with red eyes and clear fly-like wings. Males have a black/grey spot on the end of each wing, as well as two black ‘combs’ or bands on each front leg. The females do not have spots or leg bands. Females have saw-like egg-laying organs (ovipositors) that are used to cut into fruit skin. Ovipositors are easier to see when extended. A hand-lens or dissecting microscope is needed to identify ovipositor.

Eggs

0.6 mm long, oval, white, 2 filaments at one end.

Larvae

Legless, headless, up to 6 mm long at maturity, milky-white.

Pupa

3 mm long, brown, football-shaped, two stalks with small finger-like projections on ends.

Life history

Spotted Wing Drosophila overwinter as adult flies. In spring flies become active and lay eggs in ripening fruit. Based on climate model predictions, there could be up to five generations per year in B.C.

Generations overlap as flies are relatively long-lived particularly at temperatures of 20°C and cooler. Based on Japanese literature, a female can lay eggs for 10-59 days, with 7-16 eggs laid per day, and average 384 eggs per female.

Eggs hatch in 2-72 hours, larvae mature in 3-13 days, and pupae reside in fruit or outside of fruit for 3-15 days. In the lab at constant temperature, one generation takes 50 days at 12°C, 21-25 days at 15°C, 19 days at 18°C, 8.5 days at 25°C, and 7 days at 28°C. Adults are attracted to and feed on ripe and decaying fruit.

Monitoring

Flies can be monitored with cup-like traps baited with apple cider vinegar. Place traps when the temperature is consistently over 10°C and/or before fruit starts to ripen. Hang traps in the plant canopy in a shady location.

Check traps once per week and look for the Spotted Wing Drosophila adults in the bait solution. Use a hand lens or other magnifier to see the female ovipositor. Replace the bait solution each week.

Suspect fruit can also be collected and inspected for larvae.

Management

Cultural control

Where practical, remove or bury cull fruit to eliminate additional feeding and breeding sites. Keep equipment and processing areas free of old fruit. Think beyond the borders of your farm and be aware of host plants in adjacent fields.

Encourage neighbours to also manage for Spotted Wing Drosophila. Shorten picking interval where possible: pick early, clean and often.

Biological control

To date, there are no commercially available biological controls for Spotted Wing Drosophila. Research is underway to identify potential predators and/or parasites that may be useful in managing Spotted Wing Drosophila.

Chemical control

Chemical control will be required if trapping shows that adult Spotted Wing Drosophila flies are present in the field when berries begin to ripen. Adults are the target and are killed by direct spray contact and/or when they are exposed to residues of insecticide on the treated fruit and leaves.

Consider the following when planning a spray program:

  • All of the recommended products are toxic to bees. Avoid application when crops are blooming and bees are in the field. If sprays are necessary during this time, they should be applied at night
  • Use enough water and pressure to ensure adequate coverage. Flies prefer to feed in the lower, shaded part of the canopy
  • Use spray equipment that will allow effective coverage. Currently, no products are registered for aerial application
  • To limit development of resistance, rotate between the recommended products
  • A 7 to10 day spray interval may be necessary to protect fruit through the ripening period depending on temperature and pest pressure
  • A post-harvest spray may be necessary to prevent flies from building up on residual fruit and spreading to adjacent later ripening crops

The following products are registered for control of Spotted Wing Drosophila:

Danitol (31% fenpropathrin) at 779-1169 ml/ha (312 to 468 ml/ac) in a minimum of 200L/ha (80 L/ac) of water.  Begin applications when first pest activity is noticed. Spray may be directed to the soil to control insects present on fallen berries.  Do not make more than 2 applications per year. Rotate with non-pyrethroid products to delay development of resistance. Use a minimum re-treatment interval is 14 days. Do not apply within 15 days of harvest for hand harvested fields.

Delegate WG (25% spinetoram) at 315 to 420 g/ha (126 to 168 g/acre). Do not apply more than 3 times per year. Allow a re-treatment interval of at least 12 days. Do not apply within 1 day of harvest; or

Entrust (240 g/L spinosad) at 333 to 440 mL/ha (133 to 176 mL/acre). Minimum re-treatment interval is 5 days. It is OMRI approved for organic production. Do not apply more than 3 times per year and do not apply with 1 day of harvest; or

Exirel (100 g/L cyantraniliprole) at 1000 to 1500 mL/ha (400 to 600 mL/acre) in enough water to obtain good coverage. Do not apply more than 4 times per season or a maximum of 4.5 L/ha (1.8 L/acre). Allow a re-treatment interval of about 5 days. Do not apply within 1 day of harvest; or

Harvanta (50 g/L cyclaniliprole) at 1200 to 1600 mL/ha (480-640 mL/acre) in a spray volume of 935 to 1400 L/ha (374-560 L/acre) of water. This product is toxic to bees - do not apply during the blossom period. Minimum re-treatment interval is 5 days. Do not apply more than two times consecutively or more than two times within a single generation of the pest.  Do not apply more than 3 times per season or a maximum of 4.8 L/ha (1.92 L/acre). Do not apply within 1 day of harvest; or

Mako EC (407 g/L cypermethrin) at 150 to 175 mL/ha (60 to 70 mL/acre) in enough water to obtain good coverage. Do not apply more than 3 times per season.  Allow a minimum of 7 days between treatments. Do not apply within 2 days of harvest; or

Malathion 85E (85% malathion) at 975 mL/1000 L of water.  Use a maximum of 1000 L/ha (400 mL/acre) of water. Apply when the temperature is 20°C or more.  Do not apply more than 2 times per year. Do not apply within 1 day of harvest.

Success (480g/L spinosad) at 165 to 220mL/ha (66 to 88 mL/acre). Minimum re-treatment interval is 5 days. Do not apply more than 3 times per year and do not apply within 1 day of harvest; or

UP-Cyde 2.5 EC (250 g/L cypermethrin) at 245 to 285 mL/ha (98 to 114 mL/acre) in sufficient water for thorough coverage. Do not apply more than 3 times per season.  Allow a minimum of 7 days between treatments. Do not apply within 2 days of harvest.

 

Thrips

Hosts

All cane fruits.

Damage

Thrips seldom cause extensive damage but their presence in the fruit is objectionable for marketing.

Identification

Thrips are very small, slender usually dark-coloured insects.

Life history

Thrips overwinter in the soil at the base of the canes, In the spring they attack the leaves, buds and flowers. They are most abundant during July and August.

Management

Chemical control

Malathion 85 E (85% malathion) at 610 to 975 mL/1000 L of water. Spray for thorough coverage. Repeat as necessary. Do not apply within seven days of harvest; or

Malathion 500 EC (500 g/L malathion) at 1.25 to 2.0 L/1000 L of water. Spray for thorough coverage. Repeat as necessary. Do not apply within seven days of harvest. Malathion is not effective unless temperatures are above 20°C.

Do not apply malathion if bees are in the field.

Sprays applied for leafhoppers (see above) will also control thrips.

 

Two-spotted spider mites

Hosts

All blackberry varieties are susceptible to mite infestations. Pressure is most severe on crops in tunnels.

Damage

Two-spotted spider mites cause damage to the leaves, particularly during prolonged warm periods. They usually feed on the lower leaf surface, resulting in a whitish flecking on the upper surface. Heavy infestations can result in leaves drying up and dropping off.

Identification

Two-spotted spider mites are very tiny. From April to October, they are pale yellow to green, and females have two large black spots on the back and sides of the body. Orange overwintering females appear in late September and October.

Fine silk webbing is typically present on the underside of the leaves infested with mites.

Life history

In March, the spider mites begin feeding and egg-laying on the newly emerging leaves. Eggs hatch in one to two weeks and the immature mites become reproductive adults in another one to three weeks.

Mites develop faster at higher temperatures so more generations occur and numbers may increase rapidly in hot weather, particularly if native predators have been eliminated by broad-spectrum insecticides.

Monitoring

Start inspecting leaves for spider mites and mite predators in early May. Sample at least every two weeks during May and June. White speckling is a sign of mite feeding. Turn over leaves with these symptoms and examine for mites and mite predators. Use a 10 X power hand lens. Sample from four well-distributed sites per field and inspecting 10 leaflets at each site. Keep records of the date, field area and sampling results for each inspection. Include spider mites and mite predators.

No threshold levels are established for applying control sprays; however, strawberry thresholds provide some guidelines (see Strawberries section of this guide). Field history and ratio of predators to pest mites needs to be considered.

Have a knowledgeable person help identify the beneficial mites and two-spotted mites.

Management

Biological control

The relatively lesser effect of mites on blackberries than on strawberries means that greater reliance can be placed on natural controls such as predatory mites (Amblyseius fallacis) and beetles (Stethorus punctillum). If these biological control agents are present in sufficient numbers, they should adequately control spider mites.

If predators are not present due to sprays or because the planting is new, Amblyseius and Stethorus can be purchased and introduced. Preliminary tests show that a minimum of 7,000 Amblyseius/acre should be released. Apply higher rates on fields with a history of high spider mite populations. Release predators in new fields when leaves are growing and touching between the canes.

To decrease the number of predators required, they can be released into the mite ‘hotspots,’ instead of applied to the whole field.

Contact your crop consultant, supplier or BCAGRI for details on releasing biological control agents.

Chemical control

Alternate between the recommended products below to prevent mite resistance from developing.

Acramite 50WS (50% bifenazate) at 851 g/ha (340 g/acre) in a minimum of 500 L/ha (200 L/acre) of water and with enough pressure to ensure coverage on both sides of the leaves. Apply when mite populations begin to build. Do not apply more than once per season. For resistance management, rotate the use of Acramite and other Group 25 miticides with products from different groups. Do not apply within one day of harvest; or

Note: Acramite is not acceptable for some markets. Check with your packer before using.

Kanemite 15 SC (15.8 % acequinocyl) at 2.07 L/ha (0.83 L/acre) in enough water and pressure to ensure good coverage on both sides of the leaves. Apply when mite populations begin to build. For resistance management, rotate the use of Kanemite and other Group 20B miticides with products from different groups. Allow a minimum 21 days between applications. Do not apply within 1 day of harvest; or

Note: Kanemite is not acceptable for some markets. Check with your packer before using

Agri-mek 1.9 % EC (19 g/L abamectin) at 1.0 L/ha (0.4 L/acre) in at least 375 L/ha (150 L/acre) of water. Make the first application when mites first appear. Allow a minimum of seven days between applications.

Do not apply more than three times before harvest, and more than two times post-harvest. Do not apply within seven days of harvest.

Danitol (31% fenpropathrin) at 779-1169 ml/ha (312 to 468 ml/ac) in a minimum of 200L/ha (80 L/ac) of water.  Begin applications when first pest activity is noticed.  Do not make more than two applications per year. Rotate with non-pyrethroid products to delay development of resistance. Use a minimum re-treatment interval is 14 days. Do not apply within 15 days of harvest for hand harvest fields, or three days for machine-harvested fields.

Oberon (240 g/L spiromesifen) at 0.88 to 1.16 L/ha (350 to 460 mL/acre) with adequate pressure and in enough water to obtain good coverage on both sides of the leaves. Apply when mite populations begin to build. Oberon is most effective against the egg and nymph stages of mites.

Do not:

  • Apply more than three times per season
  • Re-enter fields within three days of application
  • Apply within three days of harvest

 

Blackberry disease management

 

Anthracnose (Elsinoe veneta)

Damage

This disease may cause considerable cane damage in some years, especially if weather remains wet into late spring. Infections that occur early in the season are more damaging than those that occur later.

Uneven berry ripening may result from infected canes.

Symptoms

The first symptoms are small, purplish, circular patches on the cane. As the patches enlarge, the central portion takes on a greyish colour and becomes sunken and cracked. Margins become raised and purplish. The damaged patches are often so close together that they merge, forming large, irregular areas. Canes can eventually be girdled and die.

Disease cycle

Anthracnose is caused by a fungus. Spores are produced in the small black bodies which form in the grey patches in the fall. In the spring, splashing rain carries the spores to new shoots, leaves or fruit, where infection takes place.

Monitoring

Watch for sunken grey areas with purple raised margins on canes during late spring. The cane is most commonly infected from 15 to 75 cm (6 to 30 in) above the ground.

Management

Cultural control

Cultural practices usually give adequate control. Avoid thick plantings. Do not apply excessive nitrogen. Prune out canes with symptoms of the disease. Prune out surplus canes during the growing season and old canes after harvest. Burn or bury old canes.

Biological control

None.

Chemical control

Where anthracnose has been a problem, apply:

Bordeaux Mixture (8-8-100) at the late dormant or delayed dormant (green tip) stage. Apply when foliage is dry. Refer to "Bordeaux Mixture" in the "Pest Management" section of this guide for mixing directions.

Tanos 50 DF (25% famoxadone, 25% cymoxanil) at 840 g/ha (335 g/acre) in sufficient water volume to ensure thorough coverage of the crop. Do not apply more than three times per year. At least 12 days must pass between the first and second applications.  At least 24 days must pass between the second and third applications.  Do not re-enter fields within nine days of application.  Do not apply within nine days of harvest; or

Note: Tanos 50 DF contains a Group 11 and a Group 27 fungicide. To delay fungicide resistance do not apply Tanos or other Group 11 or Group 27 fungicides more than twice in succession. Alternate with fungicides from other groups

Ferbam 76 WDG (76% Ferbam) at 3.75 kg/ha (1.5 kg/acre) as a delayed dormant (green-tip) spray. Apply in sufficient water for thorough coverage of all plant parts. Additional applications may be made using 2.0 to 2.5 kg in 1000 L of water when new canes are 25 to 30 cm tall, a third spray just before bloom, and immediately after harvest. Do not apply after berries start to form; or

Note: Ferbam is not acceptable for some markets. Check with your packer before using.

Pristine WG (25.2 % boscalid, 12.8 % pyraclostrobin) at 1.3 to 1.6 kg/ha (0.52 to 0.64 kg/acre) in enough water to obtain good coverage. Apply beginning at early bloom. Spray in rotation with other fungicides on a 7 to 14 day schedule. Use the shorter interval when disease pressure is high. Do not apply more than 4 times per crop per season. Do not apply Pristine or other products containing Group 7 or 11 fungicides more than twice in succession. Do not re-enter treated fields for hand harvesting within 24 hours of application. If mechanical harvesting, application can be made up to the day of harvest

Note: Lime sulphur, applied as a delayed dormant (green tip stage) spray to control redberry mites on blackberries, may help control anthracnose.

 

Crown gall (Agrobacterium tumefaciens)

Damage

A potentially very serious bacterial disease on blackberries that can be native in the soil or brought into a field with infected planting stock. It is vital that only plants free of crown gall be planted. Varieties vary in their degree of susceptibility to crown gall, Loch Ness appears to be highly susceptible.

Management

Cultural control

Use certified blackberry plants. Never use plants from sources where crown gall has been reported. Do not use plants containing visible galls. Where only a few plants in a field are infected, entire plants (including the complete root system) should be removed carefully and burned.

Take care when removing canes and pruning because the bacteria can be spread on the pruning shears. Disinfect pruning shears by dipping in 5% Virkon, Chemprocide or CleanGrow, or a 1:10 dilution of household bleach.

Caution: bleach is corrosive to metal blades.

Minimize root and cane injury by controlling root weevils and nematodes, avoiding close cultivation and making sure that catch plates on mechanical harvesters are working properly.

Biological control

Dygall is a formulation of a naturally occurring bacterium that is antagonistic (i.e. kills) to the crown gall bacterium. It is applied to cuttings or plant roots before planting in infested soils. It is to be used by trained nursery personnel only.

Chemical control

N/A.

 

Downy mildew (Peronospora sparsa)

Damage

The primary damage is a dry berry symptom, which is more prevalent following warm (18 to 22°C), wet weather during fruit development. ‘Triple Crown and ‘Loch Ness’ are susceptible blackberry varieties.

Symptoms

Leaf symptoms are not usually very obvious. Systemic infections appear in spring on new growth as small red spots extending along the veins together with severe leaf distortion.

Local leaf infections appear as patches on the upper surface that start as a yellow colour and become burgundy red with a brown border. Infected fruit becomes dry and shrivelled, hence the name "dry berry."

Berries may split and appear to be two berries on one stem. Fruit stems become dry and may appear red on one or more sides. The dry berry symptom may also be caused by sunburn, the dry berry mite and various other fungi.

Disease cycle

The organism is fungus-like, and is related to the water mold group, which includes Phytophthora, a common cause of root rot. The downy mildew organism may survive within the plant from year to year in roots, crowns and canes.

It may also be present in infected nursery stock. New stems and emerging leaves are infected as they develop.

During cool, wet nights, infected leaves on primocanes and fruiting laterals produce spores which are spread by wind to new leaves, flowers and developing berries. The thick foliage at the base of the plant may create the moist environment required for sporulation.

The organism can also infect and survive on rose and wild blackberry. Spores from these plants can infect cultivated blackberry.

Monitoring

Infected leaves on primocanes are the first sites for spore production. Look for systemic infections on the new growth in spring. Spores are produced on the underside of leaves, under the red spots. Initially the spore masses appear white, but they turn grey as they age.

Management

Cultural control

Try to obtain disease free planting stock. Keep roses and wild blackberries away from the crop. Remove suckers early to reduce spore production potential. Control weeds. Remove and destroy old fruiting canes immediately after harvest.

Biological control

None.

Chemical control

Zampro Fungicide (300 g/L ametoctradin, 225 g/L dimethomorph) at 0.8 to 1.0 L/ha (0.32 to 0.4 L/ac) with a non-ionic surfactant at 0.125% v/v for suppression of downy mildew.  Begin applications prior to disease development and continue on a 5 to 7 day interval.  Do not make more than two sequential applications before switching to a different mode of action. Do not make more than 3 applications per season.  Do not apply withinn 14 days of harvest.

Spring applications of Aliette for root rot will also provide some control of downy mildew.

 

Fruit rot (Botrytis cinerea)

Damage

The fungus Botrytis causes rot and yield loss. Losses will likely occur each year if fungicides are not applied to protect the blossoms and developing fruits. Losses are most severe when weather is wet through harvest.

Symptoms

Infected flowers turn brown and shrivel when they dry. Under moist conditions, grey tufts of fungus can be seen on blighted blossoms. Berries infected by Botrytis become shriveled and covered with the grey tufts when the fruit matures. Fruit can appear healthy at harvest but develop rot soon after. This is the post-harvest rot phase.

Disease cycle

The fungus primarily enters through the blossom and develops slowly until the fruit ripens. Then rot develops rapidly. Healthy fruit next to infected berries can develop rot on the bush or after harvest.

Monitoring

Watch for cane infections in the spring. They may be an important source of spores for flower infection.

Management

Cultural control

Train canes for an open canopy to promote good air circulation. Avoid excessive nitrogen fertilization. Time overhead irrigation so plants dry as quickly as possible. Cool harvested fruit as quickly as possible.

Biological control

None.

Chemical control

At least three sprays are recommended. Start when the blossoms first open and repeat at 7 to 10-day intervals. Where there are no spray volume per hectare recommendations on the label, apply from 1000 to 1500 L/ha (400 to 600 L/acre). Use the higher rate where the density of foliage and/or plant vigour is high.

Rotate sprays from the different chemical groups below to delay development of fungicide resistance.

Group M

Maestro 80DF (80% captan) at 2.25 kg/ha (0.9 kg/acre) Do not apply more often than every 7 days. Do not re-enter fields within 72 hours of application unless protective clothing is worn. For hand harvesting, do not apply within three days of harvest. For machine harvest, do not apply within two days of harvest; or

Captan 80 WDG (80% captan) at 2.0 kg in 1000 L of water/ha (0.9 kg in 400 L/acre). Do not apply more often than every seven days. Do not re-enter treated fields within 72 hours of application. Do not apply within two days of harvest; or

Captan 50 WP (50% captan) at 3.6 kg/1000 L of water/ha (1.44 kg in 400 L/acre). Do not re-enter treated fields within 72 hours of application. Do not apply within 2 days of harvest; or

Note that there is no MRL for Captan for use in blackberries in Canada.

Group 7

Cantus WDG (70% boscalid) at 560 g/ha (224 g/acre) in enough water to obtain good coverage. Apply beginning at early bloom. Spray in rotation with other fungicides on a 7 to 14 day schedule. Use the shorter interval when disease pressure is high. Do not apply more than four times per crop per season. Do not apply Lance, Cantus or other Group 7 fungicides more than twice in succession. Lance or Cantus can be applied up to the day of harvest; or

Luna Privilege (500 g/L fluopyram) at 500 mL/ha (200 mL/acre).  Apply beginning at early bloom and continue on a 7 to 10 day interval. Do not apply more than two applications per season for Botrytis or a maximum of 500 g/ha (200 g/acre) of fluopyram per year. Do not apply Group 7 fungicides more than twice in succession. Can be applied up to the day of harvest; or

Sercadis (300 g/L fluxapyroxad) at 250-666 mL/ha (100-266 mL/acre) in enough water to obatin good coverage.  Apply beginning at early bloom, prior to onset of disease development. Spray in rotation with fungicides from other groups on a 7 to 14 day schedule.  Use the shorter spray interval when disease pressure is high. Do not apply more than 3 times per crop season. Can be applied up until the day of harvest; or

Note: Sercadis will only provide suppression of Botrytis 

Kenja 400 SC (400 g/L isofetamid) at 0.99 to 1.24 L/ha (400 to 500 mL/ac). Begin applications prior to disease development and continue on a 7 to 14 day interval. When disease pressure is high use the highest rate and the shortest interval. Do not make more than two sequential applications of group 7 fungicides. Do not apply more than 3 times per year. Do not apply within 7 days of harvest; or

Group 7/9

Luna Tranquility (125 g/L fluopyram, 375 g/L pyrimethanil) at 1200 ml/ha (486 ml/acre) in a minimum of 500 L/ha (202 L/acre) of water. Begin applications in early bloom or when conditions are conducive to Botrytis and repeat as required at 7 to 10 day intervals.  Do not apply more than twice per crop per season for Botrytis.  Can be applied up until the day of harvest; or

Group 7/11

Pristine WG (25.2 % boscalid, 12.8 % pyraclostrobin) at 1.3 to 1.6 kg/ha (0.52 to 0.64 kg/acre) in enough water to obtain good coverage. Apply beginning at early bloom. Spray in rotation with other fungicides on a 7 to 14 day schedule. Use the shorter interval when disease pressure is high. Do not apply more than 4 times per crop per season. Do not apply Pristine or other products containing Group 7 or 11 fungicides more than twice in succession. Do not re-enter treated fields for hand harvesting within 24 hours of application. If mechanical harvesting, application can be made up to the day of harvest; or

Group 7/12

Miravis Prime (150 g/L pydiflumetofen, 250 g/L fludioxonil) at 0.8 to 1.0 L/ha (0.32 to 0.4 L/ac) in a minimum of 200 L/ha (80 L/ac) of water.  Make the first application at full bloom.  A second application can be made at green berry. Do not make more than 2 consecutive applications before switching to a non-group 7 or group 12 fungicide.  Do not apply within 1 day of harvest.

Group 9/12

Switch 62.5 WG (37.5% cyprodinil, 25% fludioxinil) at 775 to 975 g/ha (310 to 390 g/acre) in enough water to obtain good coverage (500 to 1000 L/ha (200 to 400 L/acre)). Apply when conditions are favourable for disease development. Do not apply Switch more than twice in succession. Alternate with fungicides from other groups. Do not apply within one day of harvest; or

Group 9/12

Tanos 50 DF (25% famoxadone, 25% cymoxanil) at 840 g/ha (335 g/acre) in sufficient water volume to ensure thorough coverage of the crop. Do not apply more than 3 times per year. At least 12 days must pass between the first and second applications.  At least 24 days must pass between the second and third applications.  Do not re-enter fields within nine days of application.  Do not apply within nine days of harvest.

Group 17

Elevate 50 WDG (50% fenhexamid) at 1.7 kg/ha (0.7 kg/acre) in enough water (up to 1000 L/ha) to obtain good coverage. Apply up to four times per season beginning at early bloom. Do not make more than two consecutive applications of Elevate. It should be alternated with fungicides from other groups to prevent development of resistance. Do not apply within 1 day of harvest; or

Group 19

Diplomat 5 SC (5% Polyoxin D zinc salt) at 463 to 926 mL/ha (185 to 370mL/acre) in enough water to obtain good coverage. Begin as a preventive application when conditions favour disease development and continue on a 7-10 day interval as needed to maintain suppression. Do not apply more than 150g a.i/ha per season or 12 months. Application can be made up to the day of harvest; or 

Group BM-01

Problad (20% BLAD polypeptide) at 2.0 to 3.3 L/ha (0.8 to 1.32 L/ac) in a minimum spray solution volume of 800 L/ha (320 L/ac). Do not apply more than 5 applications per year. Do not make more than two sequential applications before alternating with a fungicide with a different mode of action. Application can be made up to the day of harvest.

BioFungicides

Serenade Opti (QST 713 strain-Bacillus subtilis) at  1.7.0 to 3.3 kg/ha (0.68 to 1.32 kg/acre). Begin applications at the first sign of disease or when conditions favour disease development. Repeat as necessary on a 7-10 day interval. Serenade may be applied up to and including the day of harvest

Serenade Max no longer produced

Other

Oxidate 2.0 (27% Hydrogen peroxide, 2.5% Peroxyacetic acid) as a diluted spray of 1.0 L product in 100 L of water (1.0% v:v). Begin as a preventative application. Can be applied up to 8 times per year. Apply at 7 day spray intervals, reduce to 5 day spray intervals when disease pressure is high. Application can be made up to the day of harvest.

 

Leaf and cane spot (Septoria rubi)

Symptoms

The symptoms and life cycle of this disease are almost identical to anthracnose, but are caused by a different fungus. The lesions caused by Septoria are circular, while those of anthracnose are usually irregular in shape.

Disease cycle

Spore-producing structures are produced on old leaves and infected canes. They are released in the spring during rainy periods and cause new infections on leaves and canes.

Monitoring

Watch for development of spots on leaves and canes in the spring. Examine canes during the winter to estimate disease levels. Look for black pinpoint size structures within whitish spots surrounded by a reddish-brown border.

Management

Cultural control

Canes grown with alternate year fruiting programs are not usually affected by leaf and cane spot if canes are trained up as they grow. Remove old canes after harvest. Train canes early (after harvest) or wait until late spring.

Keep weeds controlled to ensure good air movement around canes.

Biological control

None.

Chemical control

Delayed dormant (green-tip) stage

Lime sulphur, applied as a spray to control redberry mites on blackberries, may help control leaf and cane blights.

Apply when first blossom buds separate

Captan and Maestro as applied for fruit rot control will also suppress Septoria. Apply before heavy rains start in the fall (early October):

Bordeaux Mixture (8-8-100) Apply when foliage is dry. Refer to "Bordeaux Mixture" in the "Pest Management" section in this guide for mixing directions.

Sercadis (300 g/L fluxapyroxad) at 250-666 mL/ha (100-266 mL/acre) in enough water to obtain good coverage.  Apply prior to onset of disease development. Spray in rotation with fungicides from other groups on a 7 to 14 day schedule.  Use the shorter spray interval when disease pressure is high. Do not apply more than 3 times per crop season. Can be applied up until the day of harvest.

 

Root rot

Damage

Root rot is not a major problem in blackberries. Damage can be severe, especially when susceptible varieties are grown, nematode populations are high, or where soils are wet for long periods.

Symptoms

Fruiting canes may suddenly wilt and die with the onset of warm weather. Plants may also be stunted and low yielding. Infected roots appear rotted and brown. The outer tissue can be sloughed off and few fibrous roots are present.

Black or purplish lesions may develop up the new canes from the ground level. Frequently, new shoots develop from the healthier portions of the crown.

Disease cycle

Root rot is caused by fungi and fungi-like organisms that act alone or as a complex. Some only infect plants that have been previously weakened by stress. They all survive in the soil for years, and begin new infections by invading fine roots. They grow through the root tissue and may grow into the plant crown and damage it.

Monitoring

During the winter, note poorly drained areas. Watch these areas for symptoms of root rot when the weather starts to warm up. After hot, dry periods, watch for wilting of fruiting canes.

Management

Cultural control

Obtain plants only from plantings free of root rot and set them out in fertile well-drained soils. Plant on raised beds to reduce damage. Control nematodes as their activity increases root rot losses.

Avoid applying high levels of nitrogen to plants infected with root rot. The nitrogen encourages excess leaf and shoot growth, and the damaged roots will not be able to supply enough water to the plants.

Subsoil between the rows in October to improve drainage.

Biological control

None.

Chemical control

Where control is necessary, apply:

Foliar application

Aliette WDG (80% fosetyl-Al) at 5.5 kg/ha (2.2 kg/acre) in a minimum of 200-1000 L/ha of water (80-400 L/acre). For spring applications, apply the first spray after bud break at 7 cm new growth and again 3–4 weeks later. For fall applications apply when conditions favour disease development (high soil moisture and cool temperatures) and then repeat if necessary 3–4 weeks later. Make the last Fall application at least 30 days before leaf drop. Do not make more than four applications per year,  two in the Spring and two in the Fall. Aliette is systemic. The product moves down from the leaves to the roots. Do not apply within 60 days of harvest.

Drench

Torrent 400SC (400 g/L cyazofamid) at 0.25 L/ha in 1000 L/ha of water (101 ml/acre in 405 L/acre of water) as a soil drench. One application can be made in the Fall and one application can be made in the Spring.  Do not use a surfactant with this drench. Do not apply within 90 days of harvest.

Orondis (100 g/L Oxathiopiprolin) at 1.3 to 2.8 L/ha (0.5 to 1.1 L/acre). Directly apply to soil with a banded drench application at a minimum of 200 L/ha, continue on a 7-14 days interval. Follow by sprinkler or drip irrigation within 24 hours to adequately distribute the product to the root zone. Use one to two applications at 7-14 days apart in Spring,  and one to two applications at 7-14 days apart during Fall. Do not make more than four applications per year. Do not apply within one day of harvest.

Orondis Gold Fungicide (35 g/L oxathiapiprolin and 105 g/L metalaxyl-M and S-isomer) at 4.57 L/ha (1.88 L/acre) in 2000 L/ha (800 L/ac) of water applied to the soil as a drench, soil-directed spray, or through irrigation. In established fields, apply in the Spring before the plants start to grow.  Apply in a one metre-wide band over the row or through drip irrigation. A second application may be made at least seven days later. 

In new plantings, apply at the time of planting in a 48 cm wide band over the row or through drip irrigation. Can be applied twice per year. Do not apply within 30 days of harvest.

 

Spur blight (Didymella applanata)

Damage

The fungus causing this disease can infect leaves, petioles (leaf stems) and canes. Fruiting laterals may be stunted and less vigorous.

Symptoms

Infections on leaves are wedge-shaped with a brown central area surrounded by a yellow band. Infections on the petioles are not noticeable, but they grow into the new canes in mid-summer forming dark brown spots surrounding buds.

The infection (brown areas) can spread up and down so that large sections of the cane are totally infected. The buds surrounded by the brown areas are not infected directly, but are greatly weakened by toxins produced by the fungus.

These weakened buds may die or, if they do leaf out in the spring, may produce weak fruiting laterals with small, yellow leaves which dry up early in the season.

Disease cycle

The infected areas on the canes remain dark brown until early winter when they become silvery-grey in colour. Over winter, small black bodies containing spores develop under the bark. The spores are released by rain in the Spring to start the cycle again.

New canes can be infected when they are 20 to 25 cm tall.

Monitoring

From May to early July, monitor for wedge-shaped brown patches on leaves to obtain an indication of spur blight levels. In the summer, watch for brown lesions around buds on the canes. During the dormant season and early Spring, check overwintering levels of the spur blight fungus by looking for cracked grey areas on the canes around buds.

Management

Cultural control

Avoid excessive nitrogen fertilization. After harvest, remove and destroy the old fruiting canes.

Biological control

None.

Chemical control

Lime-sulphur (23% calcium polysulphide) at 35 L in 1000 L of water. Apply in sufficient water for thorough coverage of all plant parts. Apply at the delayed dormant (green-tip) stage if a spray program becomes necessary. If leaves are out, spray only when they are dry to avoid damage; or

Tanos 50 DF (25% famoxadone, 25% cymoxanil) at 840 g/ha (335 g/acre) in sufficient water volume to ensure thorough coverage of the crop. Do not apply more than 3 times per year. At least 12 days must pass between the first and second applications.  At least 24 days must pass between the second and third applications.  Do not re-enter fields within nine days of application.  Do not apply within nine days of harvest.

Note: Tanos 50 DF contains a Group 11 and a Group 27 fungicide. To delay fungicide resistance do not apply Tanos or other Group 11 or Group 27 fungicides more than twice in succession. Alternate with fungicides from other groups.

Captan 80 WDG (80% captan) at 1.2 kg in 1000 L of water/ha (0.5 kg in 400 L/acre) depending on the label. Do not apply more often than every seven days. Do not re-enter treated fields within 72 hours of application. Do not apply within 2 days of harvest. Other fruit rot sprays will also help to control spur blight.

Ferbam 76 WDG. Refer to “Anthracnose” for application information.

Note: Ferbam is not acceptable for all markets. Check with your packer before using. 

 

Blackberry nematode management

 

Plant-parasitic nematodes

Nematodes are microscopic worms invisible to the naked eye. When present in great number, they greatly reduce the vigour of caneberries by feeding upon the plant roots.

Damage

Nematodes are microscopic worms that live in the soil. When plant parasitic nematodes are present in large numbers, they cause stunting and reduce vigour of blackberries by feeding on the roots. Some nematodes (dagger) are capable of transmitting viruses such as tomato ringspot. Damage usually occurs in patches in fields.

Monitoring

Test fields for nematodes before planting and fumigate if necessary. Nematodes tend to be very spotty in their distribution in a field. Thus it is very difficult to collect a representative soil sample. For this reason, careful sampling is of extreme importance if harmful nematodes are to be detected. Refer to “Nematodes” in the Berry Production Guide: Pest Management (PDF), for more information on sampling.

Management

New plantings

Raspberry plants are most susceptible to nematode damage during the year of planting. If high populations are present, control with pre-plant fumigation is necessary to allow good establishment in the first year.

New fields are best sampled for nematodes in the spring or summer before the year of planting. This allows adequate time to prepare the land for fumigation in late August or September, if necessary. Organic matter reduces effectiveness of most fumigants. Therefore, if manures are to be used, apply in spring prior to planting.

Details of soil sampling, field preparation, and fumigant application timing and method are given in the section “General Berry Pests” in this guide. Refer to this section when planning for nematode control.

If nematode damage is noticed in the year of planting, apply a nematicide as recommended for established plantings.

Established plantings

Cultural control

Good weed control practices will help prevent nematodes from building up in established plantings.

Chemical control

Velum Prime  at 500 mL/ha (200 mL/acre) through the drip irrigation system into the root zone.  Works best when applied to newly planted fields. Before applying, lightly wet the soil to reduce soil tension.  Use a minimum of 7 days between applications. Do not apply more than 500 g/ha of fluopryam (200 g/acre) per year through soil or foliar applications. Can be applied up to the day of harvest; or

Vydate L (24% oxamyl) at 9.35 L/ha (3.8 L/acre) as a soil drench in a 1m wide band centred on the row. The drench should only be applied to moist soils and should be followed with about 2 cm of irrigation to ensure that the Vydate is washed into the root zone. The drench may be applied any time between the end of harvest and the end of the growing season. Do not apply after October 31. Do not apply in the spring. Do not re-enter treated fields within 3 days of application. Apply only once per year.