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Corn

Last updated on August 14, 2024

Corn

Growing corn

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Varieties

Process market

Consult processors.

Fresh market

Listed from earliest to latest within each type.*

Sugar enhanced (SE) varieties

Yellow

Bodacious

Welcome

Kandy King

Bicolour

Temptation

Revelation (trial)

Navajo

Reflection

Double Play

Lucious

Renaissance

Supersweet (Sh2) varieties

Yellow

Sheba

ACX 725Y

Vision

Krispy King

Jubilee Supersweet

Bicolour

Double Up

ACX 734BC

Honey & Pearl

Candy Corner

Obsession

Fantastic

274

XTRA Tender 277

See your seed dealer for the most recent variety recommendations.

*Types

TripleSweet

TripleSweet varieties are 75% SE and 25% Sh2. They have the tenderness and flavour of SE varieties, along with the shelf life, sweetness and field holding ability of Sh2 types. Emergence and seeding vigour are similar to SE types, but they perform better under drought stress. Isolate TripleSweets from the Sh2 varieties.

SE

Sugary enhanced varieties. These have a sweetness in between that of the normal and Sh2 types. They must be isolated from Sh2 types, but do not need to be isolated from normal varieties.

Sh2 

Supersweets or shrunkens. These varieties have much higher sugar content than normal varieties and stay sweet longer after harvest. Kernel texture can be somewhat tough. They must be isolated by 75 to 100 m from normal (e.g. standard Jubilee) or SE varieties of similar maturity or starchy kernels will develop. They will only germinate well in warm soils.

Su 

Normal or Standard varieties are the traditionally grown sweet corns. Compared to the other types, they have lower sugar levels which convert to starch quickly resulting in short shelf-life.

 

Soil

A wide variety of soils are suitable. It is important that the soil be well-drained and well supplied with organic matter. The optimum pH range is 5.8 to 7.0. Avoid highly acidic clay soils.

 

Seed treatment

Seed should be treated with Thiram 75WP or captan seed protectants, or with an insecticide-captan mixture if seed maggots are likely to be a problem. Sh2 types should also be treated with Apron XLLS, which is registered for use only in a commercial seed treatment plant.

 

Seeding

Early Su (normal) varieties may be seeded when soil temperature reaches about 13°C. Planting of SE varieties should be delayed until soil temperature is at least 15°C. Sh2 varieties are not tolerant of cold soils and should not be seeded when soil temperature is below 18°C . For Su and SE varieties, use 11 to 17 kg/ha (4.5 to 7.0 kg/acre) of seed, depending on the seed size. For Sh2 varieties, use 6.25 to 7.5 kg/ha (2.5 to 3 kg/acre) seed. Seed is generally placed at a depth of 5 cm. For early plantings when soil is cool and moist and for Sh2 varieties, seed at a depth of 2.5 cm.

Spacing

Early varieties can be grown in rows as close as 75 cm apart, plants 20 to 23 cm apart in the row. Vigorous tall-growing varieties should be grown in rows 85 to 100 cm apart, 23 to 25 cm between plants. Processing varieties should be planted according to the row spacing and rate as required by the processor for machine harvesting.

 

Fertilizer

A soil test is necessary to determine lime, phosphate and potash requirements. Use the Vegetable Production Guide: Nutrient Management (PDF) for recommendations based on soil test results.

Broadcast most of the potash prior to planting. At the time of seeding, band 40 kg/ha (16 kg/acre) nitrogen, all of the phosphate and a maximum of 70 kg/ha (28 kg/acre) potash.

At time of last cultivation, side-dress 75 to 100 kg/ha (30 to 40 kg/acre) of nitrogen. A pre-side-dress soil nitrate test may be done to determine the optimum rate of nitrogen to apply. Contact Us or your fertilizer supplier for more information.

 

Harvesting and storage

Freshness and sweetness of normal (Su) corns diminish rapidly at high temperatures. Sugar loss is three times faster at 10°C and six times faster at 20°C than it is at 3°C. Under hot conditions corn should be hydro-cooled immediately after harvest. Corn shipped to wholesale markets should also be top-iced. Use of improved sweetness (SE, Sh2, and TripleSweets) varieties can improve sugar retention and shelf-life.

Recommended temperatures for storage and shipping of corn are 0 to 1°C at 85 – 90% relative humidity.

 

Corn weed management

Weed control is best achieved with a combination of cultural, mechanical and chemical methods. Rotate crops and herbicides to limit the buildup of difficult weeds such as atrazine-resistant redroot pigweed, lamb’s-quarters and groundsel.

Light cultivation with a rotary hoe or tineweeder, prior to crop emergence and through to the 3 – 4 leaf stage, can effectively kill emerging weeds and improve activity of some pre-emergence herbicides. When the crop is well established, use a rolling cultivator to throw soil into the row to smother escaped weeds.

Effective chemical weed control begins with knowledge of the major weed species in the field. Often a combination of preplant, pre-emergence and post-emergence treatments is necessary. See tables below.

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Pre-plow

See "Preplow cleanup of perennial weeds" section in the Vegetable Production Guide: Pest Management (PDF, 1.2 MB).

 

Pre-plant incorporated (PPI)

After working up the land thoroughly, apply one of the following treatments to the surface of a firm, moist seedbed.

Incorporate immediately by rotovating or double-discing, preferably in two different directions. Rotovators should be set at 6 cm, discs should be set at 10 to 15 cm and driven at least 6 to 10 km/hr. Plant seed at a maximum depth of 5 cm within two weeks after treatment.

Pre-plant incorporated (PPI): herbicide application rates
Product Rate PHI* Comments

Dual II Magnum

(s-metalochlor)

Group 15

PLUS:

AAtrex Liquid 480

(atrazine)

Group 5

1.25 to 1.75 L/ha
(0.5 to 0.7 L/acre)

 

PLUS:

 

2.1 to 3.1 L/ha
(0.85 to 1.25 L/acre)

 45
  • Use as a PPI treatment only in Interior B.C.
  • Controls barnyard grass and broadleaf weeds.
  • Use the lower rate on light, sandy soils and the higher rate on medium to heavy soils.
  • Rainfall is required within 10 days or a shallow cultivation will be necessary.
  • Do not incorporate deeper than 5 cm, if tillage is required.
  • Do not apply Dual II Magnum more than once per season.
  • Do not apply more than 3.1 L/ha (1.25 L/acre) of AAtrex Liquid 480 per year.
  • Do not apply to soils with less than 1% or more than 10% organic matter.
  • Most effective on fine textured soils.
  • Heavy rains after application may reduce effectiveness especially on sandy soils.
  • If weeds escape a PPI or pre-emergence application, an additional post-emergence application of Atrazine Liquid 480 may be necessary.  Do not make more than 1 re-application per year.  See Post-emergence control table on this page.
  • Do not re-enter treated area for 12 hours.

Dual II Magnum

(s-metalochlor)

Group 15

 1.25 to 1.75 L/ha
(0.5 to 0.7 L/acre)		 45
  • Use as a PPI treatment only in Interior B.C.
  • Controls barnyard grass and broadleaf weeds.
  • Use the lower rate on light, sandy soils and the higher rate on medium to heavy soils.
  • Rainfall is required within 10 days or a shallow cultivation will be necessary.
  • Do not incorporate deeper than 5 cm, if tillage is required.
  • Do not apply Dual II Magnum more than once per season.
  • Do not apply more than 3.1 L/ha (1.25 L/acre) of AAtrex Liquid 480 per year.
  • Do not apply to soils with less than 1% or more than 10% organic matter.
  • Most effective on fine textured soils.
  • Heavy rains after application may reduce effectiveness especially on sandy soils.
  • If weeds escape a PPI or pre-emergence application, an additional post-emergence application of Atrazine Liquid 480 may be necessary.  Do not make more than 1 re-application per year.  See Post-emergence control table on this page.
  • Do not re-enter treated area for 12 hours.

Primextra II Magnum

(s-metolachlor/atrazine)

Group 5 & 15

 3.0 to 4.0 L/ha
(1.2 to 1.6 L/acre)

Apply in 150 L/ha (60 L/acre) of water at 200 to 300 kPa		 N/A
  • Use as a pre-plant incorporated or a pre-emergent treatment (see Pre-emergence control table on this page).
  • Do not apply more than 1.5 kg a.i. of atrazine per ha per year.  When applied at 3 L/ha (1.2 L/acre), Primextra II Magnum contributes 1.0 kg a.i./ha of atrazine.
  • Make only one application per season.
  • Provides better grass control than atrazine alone and reduces residue hazards to following crops.

Simazine 480

(simazine)

Group 5

 In light sandy soil:
3.4 to 4.7 L/ha
(1.3 to 1.9 L/acre)

OR:

In loamy or clay soil:
4.7 to 8.3 L/ha
(1.9 to 3.3 L/acre)		 N/A
  • Controls broadleaf weeds, annual grasses, and perennial species starting freshly from seed.
  • Use 8.3 L/ha (3.3 L/acre) when grass weeds dominate.
  • Apply one week before seeding and incorporate to a depth of 2.5 cm.
  • Rainfall or irrigation is necessary to activate the simazine.
  • Resistant populations of redroot pigweed, lamb’s-quarters, groundsel and other weeds may develop from the continuous use of simazine over several years.
  • Where rates are in excess of 3.65 L/ha (1.4L/acre) do not plant rotational crops the following year.
  • After applying, do not plant any crop in the treated area in the same year except corn.
  • Simazine should not be used for more than 3 consecutive years in the same field.
  • Do not graze or cut for fodder treated immature crop (before ear emergence).

Integrity

(saflufenacil & dimethenamid – P)

Group 14 & 15

 1.1 L/ ha
(300 to 450 mL/ac)

Apply in 100 to 200 L/ha (40 to 80 L/acre) of water at 275 kPa. 		60
  • Use the high rate for season-long control of labeled weeds including barnyard grass, Canada fleabane, foxtail, lamb's quarters, redroot pigweed, yellow nutsedge and wild mustard.
  • Check label for other labeled weeds.
  • Do not incorporate greater than 3 cm. deep.
  • Do not apply to sweet corn grown on coarse soils.
  • Observe plant back interval of 22 months for peppers and onions, 100 days for cereal and 11 months for all other crops except corn.
  • Do not graze or feed treated crop to livestock for 40 days after applying.
  • Do not enter treated area for 12 hours.

*PHI = Pre-harvest interval
BUFFERS – Refer to product label for buffer requirements, and consult the Vegetable Production Guide: Pesticide Regulations and Safety (PDF).
PESTICIDE GROUP DETAILS – see the Vegetable Production Guide: Pesticide Toxicity Table (PDF).

 

Pre-emergence

Apply one of the following treatments to a well-worked, moist, firm and even seedbed after planting, but before crop emergence. Do not disturb the soil after treatment. If conditions are dry, however, a shallow incorporation will provide improved control with Dual II Magnum or Primextra.

Pre-emergence: herbicide application rates
Product Rate PHI* Comments

AAtrex Liquid 480

(atrazine)

Group 5

Light and sandy soils:

2.1 to 3.0 L/ha
(0.85 to 1.20 L/acre)

Loam and clay soils:

3.1 L/ha
(1.25 L/acre)

 45
  • Controls broadleaf weeds.
  • Do not apply more than 3.1 L/ha (1.25 L/acre) per year.
  • May be used at the lower rate following preplant Dual II Magnum to give season long control.
  • Atrazine at higher rates may cause injury to susceptible crops the following year.
  • Will not control annual grasses or Canada thistle.
  • Rainfall is required within 10 days or a shallow cultivation will be necessary.
  • If weeds escape a PPI or pre-emergence application, an additional post-emergence application may be necessary.  See Post-emergence control table on this page.

Simazine 480

(simazine)

Group 5

 In light sandy soil:
3.4 to 4.7 L/ha
(1.3 to 1.9 L/acre)

OR:

In loamy or clay soil:
4.7 to 8.3 L/ha
(1.9 to 3.3 L/acre)		 N/A
  • Controls broadleaf weeds, annual grasses, and perennial species starting freshly from seed.
  • Apply after not later than 3 to 4 days seeding, prior to emergence.
  • Apply at 8.3 L/ha (3.3 L/acre) for control of grass weeds.
  • Rainfall or irrigation is necessary to activate the simazine.
  • Resistant populations of redroot pigweed, lamb’s-quarters, groundsel and other weeds may develop from the continuous use of simazine over several years.
  • Where rates are in excess of 3.65 L/ha (1.4L/acre) do not plant rotational crops the following year.
  • After applying do not plant any crop in the treated area in the same year except corn.
  • Do not graze or cut for fodder treated immature crop (before ear emergence).
  • Simazine should not be used for more than 3 consecutive years in the same field.

Primextra II Magnum

(s-metolachlor/atrazine)

Group 5 & 15

 3.0 to 4.0 L/ha
(1.2 to 1.6 L/acre)

Apply in 150 L/ha (60 L/acre) of water at 200 to 300 kPa		 N/A
  • Use as a pre-plant incorporated or a pre-emergent treatment (see Pre-plant incorporated control table on this page).
  • Do not apply more than 1.5 kg a.i. of atrazine per ha per year.  When applied at 3 L/ha (1.2 L/acre), Primextra II Magnum contributes 1.0 kg a.i./ha of atrazine.
  • Rain or irrigation is required within 10 days, or a shallow cultivation or use of a rotary hoe is necessary for pre-emergent treatment.
  • Provides better grass control than atrazine alone and reduces residue hazards to following crops.
  • Make only one application per season.

Dual II Magnum

(s-metalochlor)

Group 15

PLUS:
 

AAtrex Liquid 480

(atrazine)

Group 5

1.25 to 1.75 L/ha
(0.5 to 0.7 L/acre)
 

PLUS:
 

 2.1 to 3.1 L/ha
(0.85 to 1.25 L/acre)

 45
  • Controls barnyard grass and broadleaf weeds.
  • Rainfall is required within 10 days or a shallow cultivation will be necessary.
  • Use the lower rate on soils with lower organic matter.
  • Do not apply Dual II Magnum more than once per season.
  • Do not apply more than 3.1 L/ha (1.25 L/acre) of AAtrex Liquid 480 per year.
  • If weeds escape a PPI or pre-emergence application, an additional post-emergence application of Atrazine Liquid 480 may be necessary.  See Post-emergence control table on this page.

Dual II Magnum

(s-metalochlor)

Group 15

PLUS:
 

Lorox L
 

(linuron)

Group 7

PLUS:

AAtrex Liquid 480

(atrazine)

Group 5

1.25 L/ha
(0.5 L/acre)
 

 

PLUS:
 

0.79 to 1.56 L (320 to 630 mL/acre)

 

 

PLUS:

2.1 to 3.1 L/ha
(0.85 to 1.25 L/acre)

 50
  • Apply in 150 L/ha (60 L/acre) of water.
  • Controls annual grasses, broadleaf weeds and triazine-resistant weeds.
  • Rainfall is required within 10 days, or a shallow cultivation or use of a rotary hoe is necessary.
  • Do not apply Dual II Magnum more than once per season.
  • Do not apply more than 3.1 L/ha (1.25 L/acre) of AAtrex Liquid 480 per year.
  • Linuron provides best control when 3 to 5 cm of irrigation or rainfall occurs within 7 to 10 days of application.
  • Do not enter treated areas for 12 hours.
  • If weeds escape a PPI or pre-emergence application, an additional post-emergence application of Atrazine Liquid 480 may be necessary.  See Post-emergence control table on this page.

Tough

(pyridate)

Group 6

Black nightshade
(0.75 L/ha (0.30 L/ac)

Redroot pigweed
(0.5 to 1.0 L/ha (0.2 to 0.4 L/ac)

Common lambsquarters
(0.75 to 1.0 L/ha (0.3 to 0.4 L/ac)

Kochia and wild mustard
(1.0 to 1.5 L/ha (0.4 to 0.6 L/ac)

 45
  • Apply in 100 L/ha (40 L/ac) of water.
  • Repeat using a 10 to 14 day application interval.
  • Do not apply more than 2 times per season.
  • May also be applied pre-seed or post-emerge (see post-emerge table).
  • Do not apply more than 1.5. L/ha (0.6 L/ac) per season.
  • Prior to applications of Tough, registered pre-emergence herbicides may be applied for grass control and may improve control of listed weeds.
  • Weeds emerging after application will not be controlled..
  • Works more rapidly at higher temperatures and when weeds are young and actively growing.
  • Do not re-enter treated area for 7 days for hand set/handline irrigation activities involving foliar  contact, for 3 days for scouting and for 12 hours for all other activities.

Integrity

(saflufenacil & dimethenamid – P)

Group 14 & 15

 0.73 to 1.1 L/ ha
(300 to 450 mL/ac)

Apply in 100 to 200 L/ha (40 to 80 L/acre) of water. 		60
  • Use the low rate for early season control of labeled weeds including foxtail, lamb's quarters, redroot pigweed and wild mustard, when an in-crop application of another registered herbicide is planned.
  • Use the high rate for season long control of labeled weeds including barnyard grass, Canada fleabane, foxtail, lamb's quarters, redroot pigweed, yellow nutsedge and wild mustard. Check label for other labeled weeds.
  • Do not apply at the high rate to sweet corn grown on coarse soils.
  • Observe plant back interval of 22 months for peppers and onions, 100 days for cereal and 11 months for all other crops except corn.
  • Do not graze or feed treated crop to livestock for 40 days after applying.
  • Do not enter treated area for 12 hours.

*PHI = Pre-harvest interval
BUFFERS – Refer to product label for buffer requirements, and consult the Vegetable Production Guide: Pesticide Regulations and Safety (PDF).
PESTICIDE GROUP DETAILS – see the Vegetable Production Guide: Pesticide Toxicity Table (PDF).

 

Post-emergence

Apply one of the following treatments to the corn crop after it has emerged, but before it is 30 cm high. Weeds should be small, less than 5 cm high.

Post-emergence: herbicide application rates
Product Rate PHI* Comments

Permit

(halosulfuron)

Group 2
47 to 70 g/ha (19.0 to 28.3 g/acre)
 
Apply in 100 L/ha (40 L/acre) of water
 30
  • Do not use on Jubilee sweet corn.
  • Apply over-the-top or with drop nozzles from the spike through row closure (10 to 12 leaf stage) of the crop.
  • Use the low rate for broadleaved weeds.
  • Use the high rate when nutsedge is present.
  • When used early post-emergence, a sequential application may be necessary to control later weed flushes.
  • A sequential treatment at the low rate may be applied only with drop nozzles semi-directed or directed to avoid application into the plant whorl.
  • Do not apply with crop oil concentrates or MSO based adjuvants.
  • Do not apply more than two times per season.
  • Repeat using a 21 day interval.
  • Do not apply more than 140 g/ha (56.6 g/acre) per season.
  • Avoid applications when conditions favour rainfall.
  • Wait 2 to 3 days to irrigate after applying.
  • Avoid disturbing treated areas (e.g.  cultivation) for 7 days after application.
  • Controls broadleaf weeds including ladysthumb, wild mustard, yellow nutsedge and redroot pigweed
  • Suppresses horsetail, shepherd's purse and smartweed.
  • Will not control ALS-inhibitor resistant weeds.
  • Applications should be made to actively growing weeds at the heights defined in the "USE RATE GUIDE" section of the label.
  • Treat actively growing nutsedge plants at the 3 to 5 leaf stage.  Heavy infestations may require sequential applications.
  • Observe plantback interval of 15 months for cabbage and carrots, 18 months for broccoli and cauliflower, 24 months for spinach and 36 months for beets.  See label for other crops listed.
  • Do not enter treated area for 12 hours.

AAtrex Liquid 480

(atrazine)

Group 5

PLUS:

Kornoil Concentrate

2.1 to 3.1 L/ha
(0.85 to 1.25 L/acre)

 

 

PLUS:

2.75 to 5.5 L/ha
(1.1 to 2.2 L/acre)

 45
  • If weeds escape a PPI or pre-emergence application of AAtrex Liquid 480, this additional post-emergence application may be necessary.
  • Do not make more than one re-application per year.
  • Do not apply more than 3.1 L/ha (1.25 L/acre) of AAtrex Liquid 480 per year.
  • Apply before corn reaches 30 cm in height.
  • Apply in 200 to 300 L/ha (80 to 120 L/acre) water.
  • The risk of atrazine residues are reduced when lower rates are used.
  • The addition of oil may cause corn injury in hot weather or on cold , wet soils.
  • Rate of Kornoil depends on water volume.  Use 300 L/ha (120 L/acre) of water at the higher rate.

Dual II Magnum

(s-metalochlor)

Group 15

PLUS:

AAtrex Liquid 480

(atrazine)


Group 5

1.25 to 1.75 L/ha
(0.5 to 0.7 L/acre)
 

 

 

PLUS:
 

 2.1 to 3.1 L/ha
(0.85 to 1.25 L/acre)

 45
  • Controls annual grasses and broadleaf weeds.
  • Do not tankmix with fluid fertilizers, oiils, oil concentrates or surfactants when using Dual II Magnum post-emerge.
  • Apply when corn is in the spike to 6-leaf stage and before weeds pass the 2-leaf stage.
  • Use the lower rate on soils with lower organic matter.
  • Do not apply Dual II Magnum more than once per season.
  • Do not apply more than 3.1 L/ha (1.25 L/acre) of AAtrex Liquid 480 per year.

Pardner

(bromoxynil)

Group 6

 1.0 to 1.2 L/ha
(0.4 to 0.48 L/acre)

Apply in 200 to 300 L/ha (80 to 120 L/acre) of water at 275 kPa		 N/A
  • Up to the four leaf stage controls green and pale smartweed, lady’s thumb, wild mustard, kochia, cow cockle, Russian thistle, stinkweed, cocklebur, common ragweed, pigweed, velvet leaf, bluebur and American nightshade.
  • Up to the eight leaf stage controls wild, tartary and common buckwheat, common groundsel and lamb’s quarters.
  • Not effective on grasses.
  • Apply when corn is in the 4 to 6 leaf stage (10 to 12 cm) and weeds are below the 8 leaf stage.
  • Drop pipes should be used when corn is beyond 8 leaf stage.
  • Temporary corn leaf scorching may occur if applied during periods of cool and wet or hot and humid weather. To reduce the chance of scorching, use the lower rate.
  • Do not add oil or surfactant.

Bromotril 240EC

(bromoxynil)

Group 6

 1.2 to 1.4 L/ha
(0.48 to 0.56 L/acre)

Apply in 200 to 300 L/ha (80 to 120 L/acre) of water at 275 kPa 		N/A
  • Up to the four leaf stage controls green and pale smartweed, lady’s thumb, wild mustard, kochia, cow cockle, Russian thistle, stinkweed, cocklebur, common ragweed, pigweed, velvet leaf, bluebur and American nightshade.
  • Up to the eight leaf stage controls wild, tartary and common buckwheat, common groundsel and lamb’s quarters.
  • Not effective on grasses.
  • Apply when corn is in the 4 to 6 leaf stage (10 to 12 cm) and weeds are below the 8 leaf stage.
  • Drop pipes should be used when corn is beyond 8 leaf stage.
  • Temporary corn leaf scorching may occur if applied during periods of cool and wet or hot and humid weather. To reduce the chance of scorching, use the lower rate.
  • Do not add oil or surfactant.

Basagran

(bentazon)

Group 6

PLUS:

Assist

1.75 to 2.25 L/ha
(0.7 to 0.9 L/acre)
 

 

 

PLUS:

1.0 to 2.0 L/ha (0.4 to 0.8 L/acre) of Assist


Apply in 100 to 400 L/ha (40 to 160 L/acre) of water at 275 to 425 kPa

N/A
  • Not effective on grasses.
  • Use the higher rate when lady’s thumb is over 7.5 cm in height or when difficult weeds such as lamb’s-quarters or pigweed are present.
  • The smaller the weeds, the better the control (see label for recommended weed growth stages).
  • Use split applications 7 to 15 days apart at 1.75 L/ha to suppress field bindweed (2.5 to 6.0 cm) or to control Canada thistle (15 to 20 cm)
  • Apply at 1 to 5 leaf stage of the crop.
  • Rainfall within 6 to 8 hours of application may reduce effectiveness.
  • Cool weather conditions or drought will delay herbicide activity and, if prolonged, may result in poor weed control.
  • Use 1.0 L/ha of Assist under hot and humid conditions.
  • Do not use treated crops for grazing.
  • Do not enter treated area for 12 hours.

Basagran Forte

(bentazon)

Group 6
 

 1.75 to 2.25 L/ha
(0.7 to 0.9 L/acre)

Apply in 100 to 300 L/ha (40 to 120 L/acre) of water at 275 to 425 kPa 		N/A
  • Not effective on grasses.
  • Controls broadleaf weeds such as common groundsel, wild mustard, Shepherd's purse.
  • Use the higher rate when lady’s thumb is over the 6-leaf stage or when difficult weeds such as lamb’s-quarters or pigweed are present.
  • The smaller the weeds, the better the control (see label for recommended weed growth stages).
  • Repeat at an interval of 7 to 15 days.
  • Use split applications 7 to 15 days apart at 1.75 L/ha to suppress field bindweed (2.5 to 6.0 cm) or to control Canada thistle (15 to 20 cm).
  • Apply at 1 to 5 leaf stage of the crop.
  • Rainfall within 6 to 8 hours of application may reduce effectiveness.
  • Cool weather conditions or drought will delay herbicide activity and, if prolonged, may result in poor weed control.
  • Can cause injury to cucumbers.
  • Do not use treated crops for grazing.
  • Do not enter treated area for 12 hours.

Compas 480 EC

(bromoxynil)

Group 6

 585 to 700 mL/ha
(237 to 283 mL/acre)

Apply in 200 to 300 L/ha (80 to 120 L/acre) of water at 275 kPa 		N/A
  • Apply any time after 4 leaf stage.
  • Use higher rates during higher infestation.
  • Temporary crop injury may occur in the form of leaf scorching (especially if applied during period of cool and wet, or hot and humid weather).
  • Do not add oil or surfactant.
  • Do not use treated crops for grazing or cut for hay until 30 days after application.

Tough

(pyridate)

Group 6

Black nightshade
(0.75 L/ha (0.30 L/ac)

Redroot pigweed
(0.5 to 1.0 L/ha (0.2 to 0.4 L/ac)

Common lambsquarters
(0.75 to 1.0 L/ha (0.3 to 0.4 L/ac)

Kochia and wild mustard
(1.0 to 1.5 L/ha (0.4 to 0.6 L/ac)

 45
  • Apply over the top of the corn up to the 8th leaf stage of the crop.
  • Apply in 100 L/ha (40 L/ac) of water.
  • Repeat using a 10 to 14 day application interval.
  • Do not apply more than 2 times per season.
  • May also be applied pre-seed or pre-emerge (see pre-emerge table).
  • Do not apply more than 1.5. L/ha (0.6 L/ac) per season.
  • Prior to applications of Tough, registered pre-emergence herbicides may be applied for grass control and may improve control of listed weeds.
  • Weeds emerging after application will not be controlled..
  • Works more rapidly at higher temperatures and when weeds are young and actively growing.
  • Do not re-enter treated area for 7 days for hand set/handline irrigation activities involving foliar  contact, for 3 days for scouting and for 12 hours for all other activities.

Callisto 480 SC

(mesotrione)

Group 27

 210 mL/ha
(85 mL/acre)

Apply in 100 to 200 L/ha (40 to 80 L/acre) of water at 205 to 300 kPa

PLUS:

0.2% v/v Agral 90		 50
  • Apply at the 3 to 6 leaf stage.
  • Make only one application per year.
  • Controls the following broadleaf weeds: lambsquarters, redroot pigweed, velvetleaf, mustard.
  • Suppresses common ragweed.
  • Do not apply to soils with less than 1% or more than 10% organic matter.
  • Do not make a foliar application of any organo- phosphate or carbamate insecticide 7 days before or 7 days after applying Callisto 480SC or severe crop injury may occur(check label for more details). 
  • Do not re-enter treated area for 12 hours.
  • A recropping interval of two years is recommended following application of Callisto for broccoli, carrot, cucumber and onion. Snap beans, peas and tomatoes may also be injured at low concentrations of Callisto 480 SC in the soil.
  • Check label for recropping precautions.
  • Consult label for crop tolerance information.

Shieldex 400SC

(tolpyralate)

Group 27

75 to 100 mL/ha

(30 to 40 mL/acre)

Apply in 140 to 470 L/ha (56 to 190 L/acre)

 

PLUS:

MSO CONCENTRATE per 1000 L spray mixture

 35
  • Control or suppression of certain grass and broadleaf weeds.
  • Make a broadcast application on corn when it is less than 30 cm tall.
  • For best results apply early post-emergence when corn and weeds are small.
  • Do not apply more than two times in a season.
  • Repeat using a 14 day interval.
  • Use the high rate for control of broadleaf weeds including lamb’s quarters and redroot pigweed.
  • Suppression only of smartweed, common purslane, shepherd’s purse and barnyard grass.
  • May be tankmixed with ammonium nitrogen fertilizer to improve overall weed control.  Check label for details.
  • May be tankmixed with atrazine to broaden or extend control.  Check label for details.  Follow the most restrictive label precautions.
  • Use 50-mesh or larger strainer screens.
  • Treat when temperatures are 21°C or more and conditions are moist.
  • For best results, treat when broadleaf weeds and grasses are <10 cm tall and actively growing.  Grasses should be treated prior to first tillering.
  • Avoid disturbing the treated area (e.g.  deep cultivation) for 7 days after applying.
  • For detasseling, do not re-enter treated area for 2 days.
  • For all other activities, do not re-enter for 12 hours.

Impact

(topramezone)

Group 27

PLUS:

Aatrex 480

(atrazine)

Group 5

PLUS:

Merge or Assist

37 mL/ha (15 mL/acre)

 

 

PLUS:

1.04 L/ha (0.45 L/acre)

 

Apply in 100 to 200 L/ha (40 to 80 L/acre) of water at 140 to 276 kPa.

 45
  • Apply when the corn is at the 1 to 7-leaf stage, broadleaf weeds are at the 1
    to 8-leaf stage and grass weeds are at the 1 to 4-leaf stage.
  • Effective against triazine resistant weeds.
  • Controls common lamb's quarters, lady's thumb, Eastern black nightshade, wild mustard and redroot pigweed.
  • Suppresses velvetleaf, common chickweed, green foxtail and barnyard grass.
  • For Impact tankmix, use Merge (0.5% v/v i.e. 5 L per 1000 L spray solution) or Assist (0.125% v/v, i.e. 12.5 L per 1000 L spray solution).
  • For Impact tankmix, use high water volume rate.
  • For Armezon tankmix, use Assist (0.125% v/v, i.e. 12.5 L per 1000 L spray solution).
  • Plants under stress can show some temporary transient bleaching.
  • Do not graze or feed treated corn for 45 days after applying.
  • Observe a plantback interval of 4 months for winter wheat.

Armezon

(topramezone)

Group 27

PLUS:

Aatrex 480

(atrazine)

Group 5

PLUS:

Assist

37 mL/ha (15 mL/acre)

 

 

PLUS:

1.04 L/ha (0.45 L/acre)

 

Apply in 100 to 200 L/ha (40 to 80 L/acre) of water at 140 to 276 kPa.

 45
  • Apply when the corn is at the 1 to 7-leaf stage, broadleaf weeds are at the 1
    to 8-leaf stage and grass weeds are at the 1 to 4-leaf stage.
  • Effective against triazine resistant weeds.
  • Controls common lamb's quarters, lady's thumb, Eastern black nightshade, wild mustard and redroot pigweed.
  • Suppresses velvetleaf, common chickweed, green foxtail and barnyard grass.
  • For Impact tankmix, use Merge (0.5% v/v i.e. 5 L per 1000 L spray solution) or Assist (0.125% v/v, i.e. 12.5 L per 1000 L spray solution).
  • For Impact tankmix, use high water volume rate.
  • For Armezon tankmix, use Assist (0.125% v/v, i.e. 12.5 L per 1000 L spray solution).
  • Plants under stress can show some temporary transient bleaching.
  • Do not graze or feed treated corn for 45 days after applying.
  • Observe a plantback interval of 4 months for winter wheat.

*PHI = Pre-harvest interval
BUFFERS – Refer to product label for buffer requirements, and consult the Vegetable Production Guide: Pesticide Regulations and Safety (PDF).
PESTICIDE GROUP DETAILS – see the Vegetable Production Guide: Pesticide Toxicity Table (PDF).

 

Atrazine resistant weeds

Atrazine resistant weeds can be controlled with the following:

Atrazine resistant weeds: herbicide application rates
Product Rate PHI* Comments

Pardner

(bromoxynil)

Group 6

 1.0 to 1.2 L/ha
(400 to 485 mL/acre)		 N/A
  • See comments in Post-emergence control table on this page.
  • Controls atrazine resistant groundsel below the 8 leaf stage.
  • To reduce the chance of burning the leaves, use the lower rate.

Bromotril 240EC

(bromoxynil)

Group 6

1.2 to 1.4 L/ha
(0.48 to 0.56 L/acre)

Apply in 100 to 400 L/ha (40 to 160 L/acre) water at 275 to 425 kPa

 N/A
  • See comments in Post-emergence control table on this page.
  • Controls groundsel below 10 cm and lamb’s-quarters below 2.5 cm, and suppresses redroot pigweed below 2.5 cm.

Basagran

(bentazon)

Group 6

PLUS:
 

Assist Oil Concentrate

1.75 to 2.25 L/ha
(0.7 to 0.9 L/acre)

PLUS:


1.0 to 2.0 L/ha
(0.4 to 0.8 L/acre)

 N/A
  • See comments in Post-emergence control table on this page.
  • Controls groundsel below 10 cm and lamb’s-quarters below 2.5 cm, and suppresses redroot pigweed below 2.5 cm.
  • Apply in 100 to 400 L/ha (40 to 160 L/acre) water at 275 to 425 kPa.

Basagran Forte

(bentazon)

Group 6

1.75 to 2.25 L/ha
(0.7 to 0.9 L/acre)

Apply in 100 to 300 L/ha (40 to 120 L/acre) water at 275 to 425 kPa

 N/A
  • See comments in Post-emergence control table on this page.
  • Controls groundsel below 10 cm and lamb’s-quarters up to the 8 leaf stage, and suppresses redroot pigweed up to the 4 leaf stage.

*PHI = Pre-harvest interval
BUFFERS – Refer to product label for buffer requirements, and consult the Vegetable Production Guide: Pesticide Regulations and Safety (PDF).
PESTICIDE GROUP DETAILS – see the Vegetable Production Guide: Pesticide Toxicity Table (PDF).

 

Corn insect management

Expand All | Collapse All
 

Aphids

These small, soft-bodied, black, winged or wingless insects are found clustered on tassels, upper leaves and silks. Large numbers on silks and under husks may make ears unmarketable on the fresh market. A very heavy infestation, particularly in late plantings, may result in incompletely filled cobs.

If large numbers of aphids are present at tassel emergence or closer to harvest, control is necessary.

Chemical control of aphids
Product Rate PHI* Comments

Assail 70WP

(acetamiprid)
 
Group 4
 56 to 86 g/ha
(22 to 34 g/acre)

Apply in 200L/ha (80 L/acre) of water.		 10
  • Repeat using a 21 day interval.
  • Maximum 2 applications per season.
  • Toxic to bees.
  • Do not detassel treated corn by hand.
  • Do not enter treated area for 10 days for hand harvesting, 12 hours for all other activities.

Cormoran

(acetamiprid & novaluron)

Group 4 & 15

500 to 700 mL/ha
(200 to 285 mL/acre)

Apply in 200 L/ha (80 L/acre) of water

 10
  • Repeat using a 21 day application interval.
  • Do not apply more than 2 times per season.
  • Toxic to bees.  Do not apply to flowering crops or weeds if bees are visiting the treatment area.
  • Toxic to certain beneficial insects.
  • If using more than 7 kg of product per day, to a maximum of 19 kg of product per day, see label for details on additional worker protection precautions.
  • Do not re-enter treated area for 12 hours. 

Closer SC

(sulfoxaflor)

Group 4C

75 to 150 mL/ha
(30 to 60 mL/acre)

 

Apply in 100 L/ha (40 L/acre) of water		 7
  • Do not make more than 2 applications per growing season.
  • Repeat at a 7 day interval.
  • Do not apply more than 300 mL/ha (120 mL/ac) per growing season.
  • Do not apply during crop flowering period or when flowering weeds are present in treatment area.
  •  Observe a plantback interval of 30 days for crops not on this label. 
  • Do not enter treated area for 12 hours.

Sivanto Prime

(flupyradifurone)

Group 4D

500 to 750 mL/ha
(200 to 300 mL/acre)

Apply in 100 L/ha (40 L/acre) of water		 7
  • Repeat at a 7 day interval.
  • Do not exceed a total of 2000 mL/ha (810 mL/acre) of product per season.
  • Toxic to bees.  Do not apply to flowering crops or weeds if bees are visiting the treatment area.
  • Do not enter treated areas for 12 hours.

Beleaf 50 SG

(flonicamid)

Group 29		 120 to 160 g/ha
(50 to 65 g/acre)

Apply in 94 L/ha (38 L/acre) of water		 0
  • Repeat at 7 day intervals.
  • Do not apply more than 3 times per year.
  • Do not apply more than 480 g/ha ( 194 g/acre) of product per season.
  • Do not re-enter treated area for 12 hours.
  • For hand harvesting, do not enter treated area for 2 days.

Movento 240SC

(spirotetramat)

Group 23

220 to 365 mL/ha
(90 to 150 mL/acre)

Apply in 200 L/ha
(80 L/acre) of water

7
  • Apply after pollen shed.
  • Repeat at 7 day intervals.
  • Maximum allowed per crop season: 1.1 mL/ha ( 445 mL/acre).
  • Use with one of the following adjuvants: non-ionic (eg. Agral 90 or Ag-Surf) or methylated seed oil (eg. Hasten).
  • Do not enter treated area for 12 hours.
  • Toxic to bees.  Do not apply during crop flowering period or when flowering weeds are present. 

*PHI = Pre-harvest interval
BUFFERS – Refer to product label for buffer requirements, and consult the Vegetable Production Guide: Pesticide Regulations and Safety (PDF).
PESTICIDE GROUP DETAILS – see the Vegetable Production Guide: Pesticide Toxicity Table (PDF).

 

Corn earworm

White, ribbed round eggs are laid by the moths on exposed fresh silk. Eggs hatch in approximately 1 week, and the caterpillars crawl down the silk into the cob, where they feed for 2 to 4 weeks. There are two to three generations per year. The caterpillars vary in colour from greenish to brownish and are marked with light and dark stripes.

Control

Note: To protect bees, do not move them within foraging distance of the treated field until at least 36 hours after spraying. See “Bee Poisoning" section of Vegetable Production Guide: Pest Management (PDF, 1.2 MB).

Kill the newly emerged larvae on the silk before they enter the cob. Treat, when eggs first observed, with one of the products listed in the table below.

Chemical control of earworm
Product Rate PHI* Comments

Lannate 

(methomyl)

Group 1A
 430 to 625 g/ha
(175 to 255 g/acre)

Apply in 240 to 900 L/ha (100 to 365 L/acre) of water		 3
  • Direct spray on silks beginning when 25% of the ears show silk.
  • Do not make more than 1 application per year.
  • Do not apply after August 15.
  • Toxic to bees.  Do not apply if bees are visiting the area.
  • Also harmful to certain beneficial insects. 
  • RESTRICTED:  can only be used by individuals holding a pesticide applicator's certificate.
  • Do not re-enter treated area for 12 hours.

Decis 5 EC

(deltamethrin)

Group 3
 250 to 300 mL/ha
(100 to 120 mL/acre)

Apply in at least 240 L/ha (96 L/acre) of water 		5
  • Do not feed or graze dairy cattle from treated fields.
  • Do not apply more than twice per year.
  • Apply only once on muck soils, before August 1.

Pounce 384 EC/ Perm-Up EC

(permethrin)
 
Group 3
 275 to 375 mL/ha
(110 to 150 mL/acre)

Apply in 325 to 450 L/ha (130 to 180 L/acre) of water

Hand harvesting:  8

Machine harvesting: 1
  • Obtain good spray coverage of ears and silks.
  • Repeat using a 3 day interval.
  • Do not make more than 4 applications per year.
  • Do not make more than 1,500 mL/ha (607 mL/acre) per season.
  • Toxic to bees, avoid spraying when bees are foraging.
  • Observe a plantback interval of 60 days for food and feed crops not listed.
  • A vegetative filter strip is required between the field edge and adjacent downhill aquatic habitats.  See label for details.
  • Do not re-enter treated area for 8 days for hand detassling or hand harvesting.
  • For all other activities do not re-enter treated area for 12 hours.

Mako

(cypermethrin)
 
Group 3

175 mL/ha
(70 mL/acre)

Apply in 300 to 500 L/ha (120 to 200 L/acre) of water

 5
  • Repeat using 7 day intervals.
  • Ensure thorough coverage.
  • Maximum 3 applications per year.
  • May kill beneficials.
  • Toxic to bees.  If applications must be made during crop blooming period, treat in the evening when most bees are not foraging.
  • If the field slopes downward to water, construct and maintain a vegetative filter strip.  Check label for details.
  • Observe a 30 day plantback interval for crops not listed.
  • Do not re-enter treated area for 12 hours.

Matador 120 EC / Silencer 120 EC

(Lambda-cyhalothrin)
 
Group 3
 187 mL/ha
(75mL/acre)

Apply in 100 to 200 L/ha (40 to 80 L/acre) of water.		 1
  • Treat when first feeding is seen on foliage.
  • Apply at 4 to 7 day intervals.
  • Will not prevent damage if insect has penetrated the ear.
  • Do not apply more than 3 times per year.
  • Very toxic to bees. Avoid spraying when bees are foraging.
  • If the field slopes downward to water, construct and maintain a vegetative filter strip.  Check label for details.
  • Check label for personal protective equipment requirements.
  • Do not re-enter treated area for 3 days for hand-harvesting, and for 12 hours for all other activities.

Rimon

(novaluron)

Group 15
 820 mL/ha
(331 mL/acre)

Apply in90 to 570 L/ha
(231 L/acre)

Hand harvest

9

Mech harvest
1
  • Apply when adult activity is 1st observed or when eggs begin to hatch.
  • Rimon targets larvae and eggs and will not control adult populations.
  • Repeat at 7 day intervals.
  • Do not apply more than 5 times per season.
  • Do not apply more than 4.1 L/ha (1.7 L/acre) per season.
  • Do not enter treated area for 9 days for hand harvesting or hand detassling.
  • Apply at a 7 day spray interval.

Coragen

(chlorantraniliprole)

Group 28
 250 - 375 mL/ha
(100 - 150 mL/ac)

Apply in 100L/ha (40 L/acre) of water. 		1
  • Thorough coverage is essential for optimum control.
  • Repeat at 3 day intervals as needed.
  • Do not make more than 4 applications per season.
  • Do not apply more than 1.125 L/ha
  • (455 mL/ac) per season.
  • Do not enter treated area for 12 hours.

*PHI = Pre-harvest interval
BUFFERS – Refer to product label for buffer requirements, and consult the Vegetable Production Guide: Pesticide Regulations and Safety (PDF).
PESTICIDE GROUP DETAILS – see the Vegetable Production Guide: Pesticide Toxicity Table (PDF).

 

Loopers

Full grown larvae are up to 2.5 cm long, olive green with a pale head and a lightly striped body. There are three pairs of legs at the head end and three pairs of fleshy legs at the rear. They move with a looping action.

Control

Loopers will be controlled when Lannate is applied for corn earworm control.

 

Wireworms

Wireworms are yellowish-brown, shiny, slender, hard-bodied worms 5 to 25 mm long which bore into corn seeds and seedlings and destroy them. In heavy infestations they will feed on established plants and greatly reduce the yield.

Control

Poncho (clothianidin) and Cruiser (thiamethoxam) are registered as a seed treatments. For use in commercial seed treatment facilities only. Not for use on farm seed treatment applicators used at planting.

See "Wireworms" section of the Vegetable Production Guide: Pest Management (PDF, 1.2 MB) for more information. If wireworms are present see table below for control options.

Chemical control of wireworms
Product Rate PHI* Comments

Force 3.0G

(tefluthrin)

Group 3
In-furrow application:
37.5 g/100 m of row
3.75 kg/ha (1.5 kg/acre) at 100 cm row spacing
 56
  • Apply directly in the seed-furrow (2 to 5 cm deep) behind the planter shoe.
  • Consult label for precise instructions on calibration of your applicator.
  • Product is not systemic  and does not control insects burrowing into or feeding on aboveground portion of  the crop.
  • Do not re-enter treated area for 12 hours.
  • Also controls seed-corn maggot.  Check label.

Cimegra

(broflanilid)

Group 30

*Note:  for 76 cm row spacing.

In-furrow:

250 mL/ha (101 mL/ac)

Or:

1.9 mL per 100 m of row

Apply in 50 L/ha (20 L/ac) of water

 N/A
  • Also controls corn rootworm.
  • Apply in-furrow or as a T-band at planting.
  • Check label for application details.
  • Do not T-band over the top of a closed furrow.
  • Ensure thorough coverage of seed and surrounding furrow when treating.
  • See label for Crop Application table to calculate rate when using row spacing that is not specified in the rate section of this table.  
  • Do not apply more than 250 mL/ha (101 mL/ac) per season.
  • A vegetative filter strip is required between the field edge and adjacent, downhill aquatic habitats.  Check label for details.
  • Observe a 30 day plantback interval for crops not listed.

*PHI = Pre-harvest interval
BUFFERS – Refer to product label for buffer requirements, and consult the Vegetable Production Guide: Pesticide Regulations and Safety (PDF).
PESTICIDE GROUP DETAILS – see the Vegetable Production Guide: Pesticide Toxicity Table (PDF).

 

Seed-corn maggot

Small, legless cream-coloured maggots attack germinating seeds.

Control

Use seed treated with diazinon, Cruiser (thiamethoxam) or Poncho (clothianidin).

 

Corn rootworm

Chemical control of corn rootworm
Product Rate PHI* Comments

Force 3.0G

(tefluthrin)

Group 3
Banded application:
37.5 g/100 m of row
3.75 kg/ha (1.5 kg/acre) at 100 cm row spacing
 56
  • Apply in a 15 to 20 cm band centred over the seed-furrow through a planter-mounted insecticide applicator.
  • Make banded application ahead of the planter's press wheels and then incorporate into the top 1 to 2 cm of soil.
  • If banded application is made behind the press wheels, ensure invorporation into the top 1 to 2 cm of soil.
  • Product is not systemic  and does not control insects burrowing into or feeding on the aboveground portions of  the crop.
  • Do not re-enter treated area for 12 hours.
  • Also controls seed-corn maggot.  Check label.

Cimegra

(broflanilid)

Group 30

*Note:  for 76 cm row spacing.

In-furrow:

250 mL/ha (101 mL/ac)

Or:

1.9 mL per 100 m of row

Apply in 50 L/ha (20 L/ac) of water

 N/A
  • Also controls wireworm.
  • Apply in-furrow or as a T-band at planting.
  • Check label for application details.
  • Do not T-band over the top of a closed furrow.
  • Ensure thorough coverage of seed and surrounding furrow when treating.
  • See label for Crop Application table to calculate rate when using row spacing that is not specified in the rate section of this table.  
  • Do not apply more than 250 mL/ha (101 mL/ac) per season.
  • Observe a 30 day plantback interval for crops not listed.

*PHI = Pre-harvest interval
BUFFERS – Refer to product label for buffer requirements, and consult the Vegetable Production Guide: Pesticide Regulations and Safety (PDF).
PESTICIDE GROUP DETAILS – see the Vegetable Production Guide: Pesticide Toxicity Table (PDF).

 

Other pests

Slugs

These slow-moving, soft-bodied slimy, legless creatures are found in various sizes up to 10 cm. They eat holes in leaves and leave a trail of mucus.

Control

Review the Corn insect management tables for more information.

Chemical control of slugs
Product Rate PHI* Comments

Sluggo Professional

(ferric phosphate)
 

Used in organics.

 25 to 50 kg/ha
(10 to 20 kg/acre)		 0
  • Best applied in evenings to moist soil.
  • Do not place in piles.
  • Sluggo Professional (PCP# 30025) is OMRI-Canada listed.  Check with your certification body before using in an organic operation.

*PHI = Pre-harvest interval
BUFFERS – Refer to product label for buffer requirements, and consult the Vegetable Production Guide: Pesticide Regulations and Safety (PDF).
PESTICIDE GROUP DETAILS – see the Vegetable Production Guide: Pesticide Toxicity Table (PDF).

OMRI-Canada = Organic Materials Review Institute of Canada

Bird control

Bird damage to corn can occur to newly emerged seedlings or to the ripening crop.

Newly sprouted seedlings may be pulled up by Canada geese, sandhill cranes (Interior), ring-necked pheasants or crows. The most effective control measure, especially for geese and cranes, is the propane exploder. However, exploders (as well as scarecrows) may have little effect on crows.

Shooting, either to frighten or kill crows, is effective but may be time-consuming. Crows, unlike the other bird species mentioned, are not a protected species and may be killed without a permit.

Propane exploders come in both stationary models and rotating models, mounted on a tripod. The latter are better because their movement, added to the sound, makes them more frightening. Propane exploders can be set to go off at varying time intervals; a five-minute interval for single shot devices is recommended. An external timer can shut the exploder off automatically at night. One 9 kg tank of propane should last at least a week.

Moving the exploders every few days will increase their effectiveness. However, birds can get used to exploders over a period of days or weeks, especially if their feeding pattern is well established. If this happens, shooting may be necessary to scare the birds off. Ordinary live ammunition, aimed to frighten but not kill birds, can be used. Even more effective are 12 gauge cracker shells, which explode about 75 to 100 m away.

If you plan to frighten waterfowl or cranes by shooting, you must obtain a “scare permit” from your District Conservation Officer, (Ministry of Environment) or from the R.C.M.P. Local municipalities also have restrictions on the discharge of firearms. If waterfowl damage is especially severe or persistent, kill permits are sometimes issued by Conservation Officers.

Most damage to ripening corn is caused by blackbirds, especially red-winged blackbirds. Corn fields adjacent to large marsh or wetland areas are most vulnerable to damage because these areas serve as nesting and roosting areas for the birds. Propane exploders are also effective deterrents to blackbirds.

Rotating exploders mounted on a tripod will protect 10 to 20 ha of corn. For further information, check out our page on Audible Bird Scare Devices.

Bird repellents 

To reduce feeding damage to ripening sweet corn caused by birds including blackbirds, blue jays, finches, robins, sparrows, starlings and wrens; apply registered treatments before damage by birds begins.  

Chemical control of birds
Product Rate PHI* Comments

Avian Control

(methyl anthranilate)

2.4 L/ha (1 L/acre)

Apply in 200 to 1000 L/ha (80 to 400 L/acre) of water

 N/A
  • Reduces feeding damage caused by birds including blackbirds, blue jays, finches, robins, sparrows, starlings and wrens.
  • Apply using groundspray equipment.
  • Use with a non-ionic surfactant at 0.06 to 0.25% v/v.
  • Repeat using a 6 to 8 day application interval.
  • Do not make more than 5 applications per year.
  • Do not apply when cobs are wet.

*PHI = Pre-harvest interval
BUFFERS – Refer to product label for buffer requirements, and consult the Vegetable Production Guide: Pesticide Regulations and Safety (PDF).
PESTICIDE GROUP DETAILS – see the Vegetable Production Guide: Pesticide Toxicity Table (PDF). 

 

Corn disease management

Expand All | Collapse All
 

Smut — head (Sporisorium) and common

Two smut diseases occur on sweet corn. Common smut is more widespread although head smut has been detected. Head smut is a potentially more serious disease as it can survive in the soil for several years. The first symptoms are swellings on the tassels and ears which are covered with a papery membrane. Eventually the interior of these galls turns into a mass of black spores which fall to the ground and remain there to infect subsequent corn crops. With common smut, the galls may appear on stems and leaves as well as ears and tassels. High temperatures (21-34°C) favour disease development.

Control

Plant tolerant or resistant varieties. Plants infected with head smut should be removed and burned as soon as they are detected to prevent inoculum buildup in the soil. Spores can be spread with harvesting equipment. Clean equipment thoroughly before entering a clean field.

Fields infested with head smut should be planted to crops other than corn at least 3-4 years. In small plantings, cut out galls before they burst and burn them.