Insect Control : New England Vegetable Management Guide : UMass Amherst

NOTES: For the insecticides listed below, one product trade name and formulation is provided for each active ingredient (AI) as an example of rates, preharvest interval (PHI), restricted entry interval (REI), and special instructions. In many cases, there are other products available with the same AI. Please see Table 27 and Insecticides Alphabetical Listing by Trade Name for more information on these insecticides.

The designation (Bee: L, M, or H) indicates a bee toxicity rating of low, moderate, or high. See the Protecting Honeybees and Native Pollinators section for more details.

The symbol * indicates a product is a restricted use pesticide. See Pesticide Safety and Use for more details.

The symbol ^OGindicates a product is listed by the Organic Materials Review Institute (OMRI) as approved for use in organic production. See Organic Certification section for more details.

Caution: Insecticides should not be applied when bees are active in the field. Avoid products with high bee toxicity during pollen shed. If application of an insecticide is necessary while the crop is blooming, select products with low bee toxicity or with short residual period; apply in the evening after the bees have left the field. See Protecting Honeybees and Native Pollinators in the Insect Management section for more suggestions on how to avoid harmful effects on pollinators.

Sprayer Type and Configuration

In sweet corn, the best coverage is achieved with a boom-type sprayer with drop nozzles. The nozzles should be arranged so that one nozzle is over the row and a double-drop system is used between rows, with the lower nozzle is directed up toward the ear and upper nozzle directed down, to bracket the ear zone. For whorl and pretassel stages, one nozzle over the row or with a single drop nozzle is adequate. Use hollow-cone nozzles at 75 to 100 psi to achieve good penetration, droplet size and coverage. Mist blowers do not provide as effective coverage of the ear zone and may result in poorer coverage in the center of the block because each row of corn acts as a filter. However, on hilly land or for other reasons a mist blower may be the most feasible sprayer option. If a mist blower is used, plant fewer rows per block for later corn when insect pressure is typically higher. Direct some spray over the canopy, so it can settle into the corn from above, as well as through the corn rows. Spray only in very calm conditions. For all sprayers, assess sprayer coverage by clipping water-sensitive cards on ears at the edge and center of the block and on both sides of the plant, then spraying water at the pressure and speed normally used.

Armyworm, Fall (Spodoptora frugiperda) and Common (Pseudaletia unipunctata)

The fall armyworm (FAW) does not overwinter in New England. Infestations result from moths carried northward on storm fronts from mid-July into September. Flights are heavier near the coast but occur inland as well. FAW flights are sporadic and unpredictable and do not necessarily correspond with corn earworm flights, so monitoring with pheromone traps in whorl-stage corn is very useful. Male adult moths are ¾" long and have mottled brown forewings with a slanting white bar across the wing and plain light tan hindwings. Female moths lay clusters of eggs on the leaves of various host plants, preferring whorl-stage corn to older corn. Eggs hatch in 2 to 10 days, depending upon temperature. Caterpillars are smooth (unlike CEW) and dark green or brown with lengthwise stripes and dark spots. Full-grown larvae reach 1.5 inches. The head capsule is dark with a distinctive light-colored marking in the form of an upside-down Y.

Feeding damage from caterpillars occurs first in whorl-stage corn, deep within the whorl, on leaves, and in the newly forming green tassel. In whorl stage corn, caterpillars produce ragged feeding damage to leaves and masses of sawdust-like excrement. As corn matures, larvae burrow into the side of corn ears, leaving behind frass and a large hole, and into the tip, making a mess of the kernels and rendering the ear unmarketable. When full grown, larvae drop to the ground and pupate in the soil. The most effective way to prevent ear damage is to apply controls during whorl and tassel stage. If flights remain high throughout ear development, silk sprays may be needed.

Monitor fall armyworm moth flight with a bucket trap (e.g., Universal Moth Trap or Multipher traps) with a lure clipped under the lid (Scentry 4-component lure is recommended) and a vapor strip placed inside the trap. Hang the trap on a stake at plant height in whorl stage corn. Identify and count FAW moths at least weekly. Flag the location well and move the trap to younger corn at tasseling. Replace the lure every 2 to 4 weeks and the vapor strip every 6 to 8 weeks.

Scout whorl and emerging tassel stage corn by checking 100 plants in groups of 10 or 20 in a V or X pattern across the field. Avoid checking only field edges and select plants randomly, not only where you can see damage. A plant is ‘infested’ if at least one caterpillar is found. If feeding damage is old and no larva is found, the caterpillar may have left the plant to pupate in the soil. A control is needed if 15% or more of plants are infested with FAW.
In emerging tassels, combine counts for ECB and FAW. For example, if 10% of plants have FAW and 12% have ECB, the combined infestation is 22%, above the 15% threshold.

Common armyworm, also known as armyworm or true armyworm, migrates from southern areas anytime from March to September. Eggs are laid on grasses and grains in preference to corn and other crops. Larvae feed at night and are grayish-green with a broad stripe on each side and a yellow-brown head. Damage is similar to fall armyworm and is often spotty and insufficient for treatment. Outbreaks are not common in New England but do occur occasionally and can cause significant damage.

alpha-cypermethrin (Fastac* EC): 2.8 to 3.8 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A.
Bacillus thuringiensis aizawai (XenTari^OG): 0.5 to 2 lb/A; PHI 0d, REI 4h, Bee: L, Group 11. Use alone to control light populations or first and second instar larvae. Add a contact insecticide to control more mature larvae and higher populations. Must be ingested; apply in evening or early morning, before larvae are actively feeding. Adherence and weather-fastness will improve with use of an approved spreader-sticker. Use high rate at cool temperatures. For resistance management, may be rotated with Bt kurstaki products (Dipel).
Bacillus thuringiensis kurstaki (Dipel DF^OG): 0.5 to 2 lb/A; PHI 0d, REI 4h, Bee: L, Group 11. Use alone to control light populations or first and second instar larvae. Add a contact insecticide to control more mature larvae and higher populations. Must be ingested; apply in evening or early morning, before larvae are actively feeding. Adherence and weather-fastness will improve with use of an approved spreader-sticker. Use high rate at cool temperatures. For resistance management, may be rotated with Bt aizawai (XenTari).
beta-cyfluthrin (Baythroid* XL): 2.8 oz/A; PHI 0d, REI 12h, Bee: H, Group 3A. For 1st and 2nd instar only.
Burkholderia spp. strain A396 (Venerate XC^OG): 1 to 4 qt/A; PHI 0d, REI 4h, Bee: M. Group UN.
carbaryl (Sevin XLR Plus): 1 to 2 qt/A; PHI 2d ears, REI 24h or 21 days for workers detasseling corn, Bee: H, Group 1A. For fall armyworm. Hand harvesting is prohibited. Highly toxic to bees. Avoid use in corn that is shedding pollen. May encourage buildup of aphids by killing natural enemies.
chlorantraniliprole (Coragen): 3.5 to 7.5 oz/A; PHI 1d, REI 4h, Bee: L, Group 28. For foliar applications.
chlorantraniliprole & lambda-cyhalothrin (Besiege*): 6 to 10 oz/A; PHI 1d, REI 24h, Bee: H, Groups 28 & 3A.
Chromobacterium subtsugae strain PRAA4-1 (Grandevo^OG): 1 to 3 lb/A; PHI 0d, REI 4h, Bee: M. Group UN.
deltamethrin (Delta Gold*): 1.5 to 2.4 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A. Apply to early instar larvae prior to boring into ear or stalk.
esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A. For fall armyworm, target first and second instar only. Direct the application to the ear zone to obtain thorough coverage of the corn silk.
gamma-cyhalothrin (Declare*): 1.02 to 1.54 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A. Use higher rate for large larvae.
indoxacarb (Avaunt): 2.5 to 3.5 oz/A; PHI 3d, REI 12h for mechanically harvested and 14 days for hand harvested, Bee: H, Group 22. Whorl through tassel emergence (prior to silking) application only. For fall armyworm only.
lambda-cyhalothrin (Warrior* II): 1.28 to 1.92 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A. Use high rate for large larvae.
methomyl (Lannate* SP): 0.25 to 0.5 lb/A; PHI 0d, REI 48h, Bee: H, Group 1A. Some sweet corn varieties may be damaged by methomyl. More severe damage may occur with the Lannate* LV formulation than with the Lannate* SP (Soluble Powder) formulation.
permethrin (Pounce* 25WP): 6.4 to 12.8 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.
spinetoram (Radiant SC): 3 to 6 oz/A; PHI 1d, REI 4h, Bee: M, Group 5. Apply as directed spray into leaf whorls or as broadcast spray.
spinosad (Entrust SC^OG): 1.5 to 6 oz/A; PHI 1d, REI 4h, Bee: M, Group 5. Apply as directed spray into leaf whorls or as broadcast spray.
zeta-cypermethrin (Mustang*): 2.8 to 4 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A.

Brown Marmorated Stink Bug (Halyomorpha halys)

See stink bugs in the insect control section of Tomato, Outdoor for information on brown marmorated stink bugs.

acetamiprid (Assail): 5.3 oz./A; PHI 7d, REI 12 h, Bee: M, Group 4A. Suppression only.
bifenthrin (Brigade* 2EC): 2.1 to 6.4 oz/A; PHI 1d, REI 12 hr, Bee: H, Group 3A. Do not make aerial or ground applications to corn if heavy rainfall is imminent.
chlorantraniliprole & lambda-cyhalothrin (Besiege*): 6 to 10 oz/A; PHI 1d, REI 24h, Bee: H, Groups 28 & 3A.
methomyl (Lannate* LV): 1.5 pt/A; PHI 0d, REI 48h, Bee: H, Group 1A.

Corn Earworm (Helicoverpa zea)

Corn earworm (CEW) moths migrate annually into the Northeast, traveling north on storm fronts, and may arrive anytime from late June through September. The heaviest numbers are found in coastal areas and up the major river valleys. The severity of infestations varies yearly and may change suddenly during the season. CEW feeds in a wide range of crops; among vegetables, its favorite crops are corn and tomato (hence, it is also known as ‘tomato fruitworm’).

Adult moths are light tan with a distinctive dark spot on each forewing, a dark band near the margin of the hind wing, and a 1.2-1.5" wingspan. Live moths have bright green eyes. Moths are active at night. Fresh silk is highly attractive for egg-laying. When migratory flights arrive, females are ready to lay eggs. Single, globe-shaped eggs are laid directly on fresh silk and hatch in 2.5 to 6 days, depending on temperature. Newly hatched caterpillars crawl down the silk channel and feed on the kernels at the tip, leaving unsightly frass. In the tip, they are protected from insecticide sprays. Corn earworm larvae may be brown, tan, green, or pink, with light and dark longitudinal stripes, and reach 1.5 to 2" when fully grown. CEW can be distinguished from FAW and ECB by the plain, golden brown head capsule and small bumps and spines that give the body a rough texture.

Monitoring moth flight with pheromone traps is key to successful season-long control because it enables farms to respond quickly to flight changes and avoid unnecessary sprays. Reports of moth trap captures at selected locations are provided in most New England states. The most accurate and timely flight information will be obtained by monitoring your own fields. Heliothis net traps baited with Hercon Heliothis zea pheromone lures are commercially available and widely used in the region. Place traps in blocks with fresh silk and count moths twice weekly to monitor the average nightly catch. Replace lures every 2 weeks and move traps to a block with fresh silk as soon as silk dries.

Sprays or other control measures must be timed to prevent larvae from entering the ear. Control depends upon maintaining insecticide coverage on the silks when eggs are being laid and hatching. Directed sprays to the ear zone provide the best control. Repeat applications to silk every 3 to 6 days, depending on trap captures, according to the chart below. If the maximum daily temperature is below 85º F for 2 to 3 days, spray intervals may be extended by 1 day. Continue treatments until 5 to 7 days before final harvest or until the silk is completely dry and brown. Use selective materials to conserve natural enemies of aphids and other pests.

Spray Intervals for Corn Earworm

Based on moth captures in Heliothis net traps

Moths/Night	Moths/Week	Spray Interval
0 - 0.2	0 - 1.4	no spray
0.2 -0.5	1.4 - 3.5	6 days
0.5 - 1	3.5 – 7	5 days
1 - 13	7 – 91	4 days
Over 13	Over 91	3 days

Bt hybrids that express the insect toxin found in Bacillus thuringiensis (Bt) in leaves, husks, and kernels offer protection against CEW, but may require additional insecticide applications to control this pest. Hybrids containing the Viptera trait a currently very effective at controlling CEW.

alpha-cypermethrin (Fastac* EC): 2.8 to 3.8 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A.
Bacillus thuringiensis aizawai (XenTari^OG): 0.5 to 2 lb/A; PHI 0d, REI 4h, Bee: L, Group 11. Use alone to control light populations and add a contact insecticide to control moderate to heavy populations. Maintain frequent spray intervals.
beta-cyfluthrin (Baythroid* XL): 1.6 to 2.8 oz/A; PHI 0d, REI 12h, Bee: H, Group 3A.
Burkholderia spp. strain A396 (Venerate XC^OG): 1 to 4 qt/A; PHI 0d, REI 4h, Bee: M. Group un.
carbaryl (Sevin XLR Plus): 1 to 2 qt/A; PHI 2d ears, REI 24h or 21 days for workers detasseling corn, Bee: H, Group 1A. Hand harvesting is prohibited. Highly toxic to bees. Avoid use in corn that is shedding pollen. May encourage buildup of aphids by killing natural enemies.
chlorantraniliprole (Coragen): 3.5 to 7.5 oz/A; PHI 1d, REI 4h, Bee: L, Group 28. For foliar applications.
chlorantraniliprole & lambda-cyhalothrin (Besiege*): 6 to 10 oz/A; PHI 1d, REI 24h, Bee: H, Groups 28 & 3A.
Chromobacterium subtsugae strain PRAA4-1 (Grandevo^OG): 1 to 3 lb/A; PHI 0d, REI 4h, Bee: M. Group UN.
deltamethrin (Delta Gold*): 1.5 to 2.4 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A. Apply to early instar larvae prior to boring into ear or stalk.
esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.
gamma-cyhalothrin (Declare*): 1.02 to 1.54 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A. For control before larvae bore into plant stalk or ear.
lambda-cyhalothrin (Warrior* II): 1.28 to 1.92 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A.
methomyl (Lannate* SP): 0.25 to 0.5 lb/A, 0.33 to 0.5 lb/A for whorl as needed; PHI 21d, REI 48h, Bee: H, Group A. Some corn varieties may be damaged by methomyl. More severe damage may occur with the Lannate* LV formulation than with the Lannate* SP (Soluble Powder) formulation. May not provide effective control under high corn earworm pressure. Effective as ovicide and larvicide.
methoxyfenozide + spinetoram (Intrepid Edge): 8 to 12 fl oz/A; PHI 3d ears, REI 4h, Bee: M, Group 5 & 18. Apply as broadcast or direct spray to ear zone. Ensure thorough wetting of the silks. A 2-day re-treatment schedule may be necessary at silking.
nuclear polyhedrosis virus of Helicoverpa zea (Gemstar^OG): 4-10 fl. oz./A; PHI 0d, REI 4h, Bee:L, Group UN. Do not tank mix with Bt products. Frequent application at low rates is usually more effective than infrequent application at high rates.
permethrin (Pounce* 25WP): 6.4 to 12.8 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.
soybean oil (Golden Pest Spray Oil^OG): 2 gal/A applied when insects first appear (repeat weekly for additional control), 0.5 ml applied by hand directly to silk within 6 to 7 days after 50% of the ears are silking;PHI 0d; REI 4h, Bee: L, Group 25. Apply at least 5 days after silk initiation to avoid tip injury, and before 7 days after silk initiation to gain optimum control. Mix with Bacillus thuringiensis, spinosad or neem for improved control. One application per field. Commercial oil applicators (i.e., Zea-later) are available.
spinetoram (Radiant SC): 3 to 6 oz/A; PHI 1d, REI 4h, Bee: M, Group 5. Apply as broadcast or directed spray into ear zone.
spinosad (Entrust SC^OG): 3 to 6 oz/A; PHI 1d, REI 4h, Bee: M, Group 5. Apply as directed spray to ear zone or as broadcast spray. Ensure thorough wetting of silks. Effective for low to moderate CEW pressure. May be less effective when CEW pressure is high (13 or more moths/night in pheromone trap) or when a 3-day spray schedule is warranted. A 1 to 2-day re-treatment schedule may be necessary at silking.
zeta-cypermethrin (Mustang*): 2.8 to 4 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A.

Corn Leaf Aphid (Rhopalosiphum maidis)

The corn leaf aphid (CLA) is blue-green or black, with black legs. These aphids overwinter as eggs or females on grass weeds and grains, including barley and wheat. When these cereals mature, winged aphids develop and migrate to corn and wild grasses. Both winged and wingless female aphids occur together. Females produce live young (nymphs), which mature in as little as 6 days, resulting in many generations per year. In corn, CLA first colonizes whorl leaves and the immature tassel. Populations may become numerous enough to interfere with pollen shed, stunt plants, and infest layers of the husk with aphids. Maize dwarf mosaic virus may be spread by the corn leaf aphid, though the most important vector for this disease is the green peach aphid. In addition, aphids excrete a sugary liquid called ‘honeydew’, which coats leaves and husks and encourages the growth of sooty mold fungus. The presence of aphids and honeydew on corn husks reduces their marketability. Varieties with purple or green tassels seem less susceptible to aphid build-up than those with yellow tassels. Ample rainfall or irrigation during the silk stage can reduce or eliminate aphid damage. Natural enemies reduce aphid numbers but may not provide adequate control, especially in dry seasons. Whenever possible, conserve predators and parasites by using selective insecticides to control caterpillars. Sweet corn plantings that are seeded before 10 June are generally not bothered by corn leaf aphids. Monitor for aphids while scouting whorl or pre-tassel stage corn for ECB or FAW in July and August. Pre-tassel stage sprays may be needed when 50% of the plants are infested or if 25% have heavy infestations. Sprays applied before 50% of the tassels emerge are more effective than later sprays.

acetamiprid (Assail): 2.1 to 2.9 oz./A; PHI 1d, REI 12h, Bee: M, Group 4A.
alpha-cypermethrin (Fastac EC*): 2.8 to 3.8 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A.
Chromobacterium subtsugae strain PRAA4-1 (Grandevo^OG): 2 to 3 lb/A; PHI 0d, REI 4h, Bee: M. Group UN.
deltamethrin (Delta Gold*): 1.5 to 2.4 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A. Suppression only.
esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A. For optimum results, direct spray at the aphid population to achieve maximum coverageof the exposed insects. Aphids not contacted by the spray, wuch as in whorls and leaf axils, may not be adequately controlled.
flupyradifurone (Sivanto): 7 to 14 fl oz/A; PHI 7d, REI 4h, Bee: M, Group 4D.
gamma-cyhalothrin (Declare*): 1.02 to 1.54 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A. Suppression only.
lambda-cyhalothrin (Warrior* II): 1.28 to 1.92 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A. Suppression only.
methomyl (Lannate* SP): 0.25 to 0.5 lb/A; PHI 0d for ears, 3d if used for forage, REI 48h, Bee: H, Group 1A. Some sweet corn varieties may be damaged by methomyl.
petroleum oil (Suffoil X^OG): 1 to 2 gal/100 gal water; PHI 0d, REI 4h, Bee: L.
thiamethoxam (Cruiser 5FS): 1.28 to 5.1 oz/100 lb of seed; REI 12h, Bee: H, Group 4. Systemic seed treatment. Use standard slurry seed treatment equipment to ensure uniform coverage of kernels. For early season protection from corn leaf aphid.

Cutworms, including Black Cutworm (Agrotis ipsilon)

Black cutworm is the most common of the many cutworm species that damage corn in New England. Adults are night-flying tan and black moths, while the caterpillars are dark grey to black and up to 2" long. Moths from the South arrive between March and June. Eggs are laid mostly on grasses and winter annual weeds, usually near field areas prone to flooding. Certain fields tend to have a history of repeated cutworm damage. The larvae feed after dark while hiding under the soil surface during the day. There are 2 to 3 generations per year, but usually only the first generation, which produces larvae in May and June, damages corn. Small larvae feed on leaves; larger larvae occasionally cut seedlings off near the soil line. Adults can be monitored with a yellow and white Unitrap from March through May. A catch of over 40 moths before June indicates that frequent spring and early summer scouting is prudent. Scout problem fields weekly, checking at least 100 plants for leaf feeding and cut stems, especially near field margins. Spot spray heavily hit areas or edges of the field if 5% of the plants have been cut down. For best results, apply insecticides between midnight and dawn while cutworms feed aboveground. Foliar-applied rescue treatments are recommended over preventative soil-applied insecticides. Ground beetles, parasitic flies and wasps, and other general predators help reduce populations. When corn follows sod/hay in rotation, fall-plowing may lower cutworm populations by reducing spring egg-laying sites. Weedy and reduced-till fields tend to suffer the most damage.

alpha-cypermethrin (Fastac* EC): 2.2 to 3.8 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A.
beta-cyfluthrin (Baythroid* XL): 0.8 to 1.6 oz/A; PHI 0d, REI 12h, Bee: H, Group 3A.
beta-cyfluthrin + tebuprimphos (Aztec* 2.1G): 6.7 oz/1000 row ft; REI 48h, Bee: H, Groups 3A and 1B. Must be incorporated into soil to at least 1" depth. Apply at planting as band or in-furrow.
bifenthrin (Capture* LFR): 3.4 to 13.6 oz/A for at-plant applications; 4 to 5.3 oz/A for pre-plant incorporation applications; 3.4 oz/A for pre-emergence applications; PHI 1d, REI 12h, Bee: H, Group 3A. Apply as T-band over open furrow or over the row on soil surface, in-furrow with the seed, or incorporated pre-planting to seed planting depth. Black cutworm only for PPI and PRE applications.
bifenthrin + Bacillus amyloliquefaciens strain D747 (Ethos XB): 3.4 to 17 fl oz/A, PHI 1d, REI 12h, Bee: H, Group 3A and BM 02 fungicide. Apply as a 5 to 7 inch band (T-band) over an open furrow, or in-furrow with the seed mixing. Can be mixed directly with liquid fertilizer. Biofungicide suppresses pathogens responsible for damping off.
carbaryl (10% Sevin Granules): 10 lb/A; PHI 2d, REI 12h or 21 days for workers detasseling corn, Bee: H, Group 1A. Ground broadcast equipment applications only. Hand harvesting prohibited.
chlorantraniliprole & lambda-cyhalothrin (Besiege*): 6 to 10 oz/A; PHI 1d, REI 24h, Bee:H, Groups 28 & 3A.
deltamethrin (Delta Gold*): 1 to 1.5 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A. Apply to early instar larvae prior to boring into ear or stalk.
esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.
ethoprop (Mocap* 15%G): 20 lb/A; REI 48h, Bee: H, Group 1B. Apply as broadcast 3 days before planting to at-planting time. Immediately incorporate immediately into top 2" of soil.
gamma-cyhalothrin (Declare*): 0.10 to 0.18 oz/1000 row ft for at-plant soil application in T-band or band only, 0.26 oz/1000 row ft permitted for at-plant soil application in New Hampshire only, 0.77 to 1.28 oz/A foliar; PHI 21d, REI 24h, Bee: H, Group 3A.
lambda-cyhalothrin (Warrior* II): 0.33 fl oz/1,000 ft. as T-band or furrow application at planting, 1.28 to 1.92 oz/A foliar; PHI 1d, REI 24h, Bee: H, Group 3A.
methomyl (Lannate* SP): 0.5 lb/A; PHI 0d, REI 48h, Bee: H, Group 1A. Some sweet corn varieties may be damaged by methomyl. More severe damage may occur with the Lannate* LV formulation than with the Lannate* SP (Soluble Powder) formulation. Variegated cutworm only.
permethrin (Pounce* 25WP): 6.4 to 12.8 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.
spinosad (Seduce^OG): 20 to 44 lb/A or 0.5 to1 lb/1000 sq ft.; PHI 1d, REI 4h, Bee: M, Group 5. Spread bait on soil around plants. Reapply after heavy rain or at least every 2 to 4 weeks but not more than 3 times per 30 days.
tefluthrin (Force* CS): 0.46 to 0.57 oz/1000 row feet; REI 48h, Bee: H, Group 3A. For t-banded or in-furrow applications at planting.
thiamethoxam (Cruiser 5FS): 1.28 to 5.1 oz/100 lb of seed; REI 12h, Bee: H, Group 4A. Systemic seed treatment. Use standard slurry seed treatment equipment to ensure uniform coverage of kernels. For early season protection from black cutworm.
zeta-cypermethrin (Mustang*): 2.24 to 4 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A.

European Corn Borer (Ostrinia nubilalis)

European corn borer (ECB) is a resident pest with 2 generations per year in southern and central New England and 1 generation in northern New England. Sweet corn is one of over 200 crop and weed host plants of this pest; other vegetable crops affected include beans, peppers, and potatoes. Larvae overwinter in stalks of corn and other host plants and pupate in the spring. Adult moths emerge in late May or early June and mate in weedy or grassy areas. Growing degree days (GDD) with a base temperature of 50°F may be used to predict the beginning of moth flight (374 GDD), first eggs (450 GDD), and peak flight (631 GDD). The moths are about ¾" long, light brown in color, with lighter bands on the wings. Three to 7 days after emergence, depending on temperature, females begin to lay flat, white egg masses on the underside of leaves in early corn. Eggs hatch in about 5 to 7 days (100 GDD). ECB larvae are light-colored, with a pattern of small dark spots on each segment. The head capsule is flattened and black or dark brown. Newly hatched larvae are 1/8" long, and full-grown larvae are 3/4" to 1" long. Larvae feed in the whorl, leaving pinhole damage and in the succulent emerging tassel, creating brown frass in the florets. As the corn matures, these larvae move downward, bore into the stalk, and tunnel into ears through the side or tip. Pupae form inside larval tunnels in the stalk. A second flight begins in mid-July to mid-August, depending on location and the seasonal growing degree day accumulation (beginning of second flight, 1400 GDD; first eggs 1450 GDD; egg hatch 1550 GDD). When moths are active during silking, eggs are laid on leaves near the ear, and larvae move directly into the ear by tunneling through the husk or down the silk channel.

Since the ECB overwinters as a mature larva in corn stalks and stubble, plowing under corn residue in the fall or early spring will help control this pest. Fields that have been in sweet corn or field corn for a long time tend to have higher pressure from ECB. Weedy fields also have higher pressure. Natural enemies include the twelve-spotted ladybeetle, which preys on eggs and small larvae. Releases of Trichogramma striae, a tiny parasitic wasp that attacks ECB eggs, can reduce the need for insecticide applications. See Table 23, Biological Controls for Insect Pests for more information.

ECB flight can be monitored with 2 Scentry Heliothis net traps baited with either a New York E (II) or Iowa Z (I) lure placed at least 50' apart in weedy borders of corn fields with the bottom at weed height. Both types of lures are needed in New England because both E and Z strains are present. Check traps once or twice per week and replace lures every 2 weeks. Once flight is detected, corn with newly emerging tassels should be scouted weekly for the presence of ECB larvae by inspecting the tassels of 50 to 100 plants in groups of 5 to 20 plants throughout the field. Treat if more than 15% of the plants have one or more larvae present. Timing sprays for tassel emergence reaches larvae in the whorl and the young tassel. A sprayer configuration with one nozzle directed into the tassel and a single drop nozzle to the upper parts of the plant gives the best control. At high infestation levels, 2 applications may be needed to provide control. The use of selective products to control ECB will conserve natural enemies of aphids and ECB.

Corn started under plastic or row cover often reaches the silk stage during the first flight of ECB, such that the first eggs laid hatch during ear development. As a result, ears can be heavily infested by this pest even though scouting in early tassel stage did not show any feeding damage or larvae. If plants are in silk and moths are active, it is important to protect developing ears. This is also true for late-season corn during the second ECB flight, especially when other caterpillar pests are absent.

Genetically modified Bt hybrids that express the insect toxin found in Bacillus thuringiensis (Bt) generally provide adequate defense against European corn borer and may not require additional insecticide applications, but scouting is still recommended to assess ECB and other pests.

alpha-cypermethrin (Fastac* EC): 2.8 to 3.8 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A.
Bacillus thuringiensis aizawai (XenTari^OG): 0.5 to 2 lb/A; PHI 0d, REI 4h, Bee: L, Group 11. See the general recommendations for Bt kurstaki below. For resistance management, may be rotated with Bt kurstaki products.
Bacillus thuringiensis kurstaki (Dipel DF^OG): 0.5 to 2 lb/A; PHI 0d, REI 4h, Bee: L, Group 11. Must be ingested. Apply when larvae are actively feeding. Ensure good coverage and use a spreader sticker. Use a shorter spray interval (4 to 5 days) and high rates under high borer pressure. For resistance management, may be rotated with Bt aizawai (XenTari).
Burkholderia spp. strain A396 (Venerate XC^OG): 1 to 4 qt/A; PHI 0d, REI 4h, Bee: M. Group un.
beta-cyfluthrin (Baythroid* XL): 1.6 to 2.8 oz/A; PHI 0d, REI 12h, Bee: H, Group 3A. Applications must be made prior to larva boring into the plant.
carbaryl (Sevin XLR Plus): 1.5 to 2 qt/A; PHI 2d ears, REI 24h or 21 days for workers detasseling corn, Bee: H, Group 1A. Hand harvesting is prohibited. Highly toxic to bees. Avoid use in corn that is shedding pollen. May encourage buildup of aphids by killing natural enemies.
chlorantraniliprole (Coragen): 3.5 to 7.5 oz/A; PHI 1d, REI 4h, Bee: L, Group 28. For foliar applications.
chlorantraniliprole & lambda-cyhalothrin (Besiege*): 6 to 10 oz/A; PHI 1d, REI 24h, Bee: H, Groups 28 & 3A.
Chromobacterium subtsugae strain PRAA4-1 (Grandevo^OG): 1 to 3 lb/A; PHI 0d, REI 4h, Bee: M. Group UN.
deltamethrin (Delta Gold*): 1.5 to 2.4 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A. Apply to early instar larvae prior to boring into ear or stalk.
esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.
gamma-cyhalothrin (Declare*): 1.02 to 1.54 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A.
indoxacarb (Avaunt): 2.5 to 3.5 oz/A; PHI 3d, REI 12h for mechanically harvested and 14 days for hand harvested, Bee: H, Group 22. Whorl through tassel emergence (prior to silking) application only.
lambda-cyhalothrin (Warrior* II): 1.28 to 1.92 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A. Use higher rates for large larvae.
methomyl (Lannate* SP): 0.25 to 0.5 lb/A on ears 1 to 3 days or as needed; PHI 0d, REI 48h, Bee: H, Group 1A. Treat a small area of the field to determine cultivar sensitivity before spraying entire field. Phytotoxicity may occur on some varieties. More severe damage may occur with the Lannate* LV formulation than with the Lannate* SP (Soluble Powder) formulation.
methoxyfenozide (Intrepid 2F): 4 to 16 oz/A; PHI 3d, REI 4h, Bee: L, Group 18. Direct application at the whorl for early season infestations. Broadcast over row for mid- to late-season infestations.
methoxyfenozide + spinetoram (Intrepid Edge): 4 to 12 fl. oz./A; PHI 3d, REI 4h, Bee: M, Group 5 & 18. Direct application at the whorl for early season infestations.
permethrin (Pounce* 25WP): 6.4 to 12.8 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.
spinetoram (Radiant SC): 3 to 6 oz/A; PHI 1d, REI 4h, Bee: M, Group 5. Apply as directed spray into leaf whorls or as broadcast spray.
spinosad (Entrust SC^OG): 1.5 to 6 oz/A; PHI 1d, REI 4h, Bee: M, Group 5. Apply as directed spray into leaf whorls or as broadcast spray. Time applications to coincide with peak egg hatch of each generation. Frequent treatments may be necessary when the crop is growing rapidly, during silking or under heavy pest pressure.
zeta-cypermethrin (Mustang*): 2.8 to 4 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A.

Flea Beetle, Corn (Chaetocnema pulicaria)

Corn flea beetles are black, tinged with bronze or bluish-green, and overwinter in plant residue around the fields. They move to corn seedlings in early spring, feeding and laying eggs in the soil. Direct feeding damage is not significant, but economic damage can be caused by Stewart’s bacterial wilt, which is vectored by the beetles. Cold winters reduce the risk of this disease, while mild winters improve beetle survival and, hence, transmission of wilt. A Winter Temperature Index uses the sum of the average monthly temperatures of December, January, and February (in ºF) to forecast the Stewart’s wilt severity for the season: wilt is predicted to be absent if the Index is <90º F, intermediate if 90º F to 100º F, and destructive if >100º F. The disease may appear on the earliest plantings and grow worse on succession plantings of susceptible varieties. Use resistant or tolerant varieties where possible, especially on early plantings (see Sweet Corn Varieties Section). Spunbonded row covers protect plants against this pest. Scout on sunny, calm days when beetles are active. Start applications when plants are in the spike stage if beetles are present and causing damage, especially on susceptible varieties. Apply additional treatments as needed.

acetamiprid (Assail): 4 to 5.3 oz./A; PHI 7d, REI 12 h, Bee: M, Group 4A.
alpha-cypermethrin (Fastac* EC): 2.2 to 3.8 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A.
beta-cyfluthrin (Baythroid* XL): 0.8 to 1.6 oz/A; PHI 0d, REI 12h, Bee: H, Group 3A.
carbaryl (Sevin XLR Plus): 1 to 2 qt/A; PHI 2d ears, REI 24h or 21 days for workers detasseling corn, Bee: H, Group 1A. Hand harvesting is prohibited. Highly toxic to bees. Avoid use in corn that is shedding pollen. May encourage buildup of aphids by killing natural enemies.
chlorantraniliprole & lambda-cyhalothrin (Besiege*): 6 to 10 oz/A; PHI 1d, REI 24h, Bee:H, Groups 28 & 3A.
deltamethrin (Delta Gold*): 1 to 1.5 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.
esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.
gamma-cyhalothrin (Declare*): 1.02 to 1.54 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A.
lambda-cyhalothrin (Warrior* II): 1.28 to 1.92 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A.
methomyl (Lannate* SP): 0.25 to 0.5 lb/A; PHI 0d, REI 48h, Bee: H, Group 1A. Phytotoxicity may occur on some varieties.
permethrin (Pounce* 25WP): 6.4 to 12.8 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.
phorate (Thimet* 20-G): 4.5 to 6 oz/1,000 row feet; PHI 30d, REI 48h, Bee: H, Group 1B. Apply in a 7" band over the row at planting and lightly incorporate. Granules must be incorporated into the soil. DO NOT use in-furrow.
terbufos (Counter* 20G): 4.5 to 6 oz/1,000 row feet for any row spacing; REI 48h, Bee: M, Group 1B. Place granules in seed furrow behind planter shoe or in a 4-5" band over the row, and lightly incorporate.
thiamethoxam (Cruiser 5FS): 1.28 to 5.1 oz/100 lb of seed; REI 12h, Bee: H, Group 4A. Systemic seed treatment. Use standard slurry seed treatment equipment to ensure uniform coverage of kernels. For early season protection from corn flea beetles.
zeta-cypermethrin (Mustang*): 2.24 to 4 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A.

Japanese Beetle (Popillia japonica)

These beetles feed on corn silk but are usually controlled by sprays directed at controlling ECB and corn earworm.

acetamiprid (Assail): 5.3 oz./A; PHI 7d, REI 12h, Bee: M, Group 4A.
alpha-cypermethrin (Fastac* EC): 2.2 to 3.8 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A. Adults only.
beta-cyfluthrin (Baythroid* XL): 1.6 to 2.8 oz/A; PHI 0d, REI 12h, Bee: H, Group 3A. Adults only.
carbaryl (Sevin XLR Plus): 1 to 2 qt/A; PHI 2d ears, REI 24h or 21 days for workers detasseling corn, Bee: H, Group 1A. Hand harvesting is prohibited. Highly toxic to bees. Avoid use in corn that is shedding pollen. May encourage buildup of aphids by killing natural enemies.
chlorantraniliprole & lambda-cyhalothrin (Besiege*): 6 to 10 oz/A; PHI 1d, REI 24h, Bee: H, Groups 28 & 3A. Adults only.
deltamethrin (Delta Gold*): 1.5 to 2.4 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A. Adults only.
gamma-cyhalothrin (Declare*): 1.02 to 1.54 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A. Adults only.
lamba-cyhalothrin (Warrior* II): 1.28 to 1.92 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A. Adults only.
pyrethrin (PyGanic EC5.0^OG): 4.5 to 17 oz/A; 0.25 to 0.50 oz/gal, 3 gal/1000 sq ft in greenhouse for backpack sprayers; PHI 0d, REI 12h, Bee: M, Group 3A.
zeta-cypermethrin (Mustang*): 2.24 to 4 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A. Adults only.

Sap Beetles, Fourspotted (Glischrochilus quadrisignatus) and Dusky (Carpophilus lugubris) Sap Beetle

Sap beetle problems are more likely to occur on farms producing various fruit and vegetable crops. Adult beetles are 3/16" long and are black (Dusky sap beetle) or black with orange spots (Fourspotted sap beetle, also known as ‘picnic beetle’). They survive the winter as pupae or adult beetles under soil or plant debris in fields or under leaf litter along hedgerows and field margins. Eggs may be deposited in rotting fruit or discarded vegetable debris (cull piles), in wounds created by corn borer or birds, and on silk or in kernels at the tip of the ear. Eggs are milky white and resemble tiny grains of rice, about 1/16" long. The larva is a white or light yellow grub that resembles a tiny, thin caterpillar or maggot. Larvae hollow out developing kernels, and damage may be found in the tip and scattered through the upper half of the ear. Full-grown larvae drop to the ground to pupate in the soil. The marketability of ears declines when damage, larvae, or adults are present on or in kernels. Adults feed on pollen, sap, silk, and injured or rotting fruit. Males have an aggregation pheromone that attracts other beetles, both male and female. Adults move to corn at full tassel to feed on pollen and build up as corn matures and silk turns brown. There are 2 to 4 generations per year, with peak infestations in July (larvae) and late July and August (adults).

Cultural controls are essential to managing sap beetles. Ears with exposed tips, especially super sweet and Bt varieties, are more susceptible to infestation. Research has shown that the tip cover's length and tightness are important to reduce infestations. Some varieties with long, tight tip covers include Accord, Argent, Avalon, Awesome, Bon Jour, Cuppa-Joe, Easy Money, Fantasia, Ka-Ching, Precious Gem, Prime Plus, Profit, Providence, and Renaissance. To prevent or reduce damage, select varieties with good tip cover, use clean cultivation, and control birds and ear-infesting caterpillars. Eliminate or bury deeply any cull piles or other areas with decaying vegetables or fruit, including infested ears. Do not leave infested blocks standing; mow aggressively to chop ears as soon as the block is finished. Deep plowing may be necessary after harvest to bury ears at least 4" deep if infestations are high.

Scout blocks at full tassel and early silk to determine if beetles are present. Unfortunately, there are no specific thresholds based on scouting. Insecticides may be warranted in fields with a previous history of 10% ear damage. Research in Maryland showed that ear infestation begins just after silk emerges and that 1 or 2 applications made 3 and 6 to 7 days after silking begins is more effective than later or more applications. Insecticides will reduce the number of damaged kernels and ears but will not completely control heavy infestations. Sap beetle adults and larvae are not susceptible to the Bt toxin that is present in Bt corn. Efficacy trials have shown that carbaryl (Sevin), lambda-cyhalothrin (Warrior II), bifenthrin (Bifenture), and methomyl (Lannate) are more effective than most other insecticides. However, carbaryl cannot be used during the early silk period while corn is shedding pollen and does not allow for hand harvesting after use.

acetamiprid (Assail): 4-5.3 oz/A; PHI 1d, REI 12h, Bee: M, Group 4A.
alpha-cypermethrin (Fastac* EC): 2.2 to 3.8 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A. Adults only.
carbaryl (Sevin XLR Plus): 1 to 2 qt/A; PHI 2d, REI 12h, Group 1A. 1 to 2 qt/A; PHI 2d ears, REI 24h or 21 days for workers detasseling corn, Bee: H, Group 1A. Hand harvesting is prohibited. Highly toxic to bees. Avoid use in corn that is shedding pollen. May encourage buildup of aphids by killing natural enemies.
chlorantraniliprole & lambda-cyhalothrin (Besiege*): 6 to 10 oz/A; PHI 1d, REI 24h, Bee:H, Groups 28 & 3A. Adults only.
esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A. Adults only.
gamma-cyhalothrin (Declare*): 1.02 to 1.54 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A. Adults only.
lambda-cyhalothrin (Warrior* II): 1.28 to 1.92 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A. Adults only.
malathion (Malathion 57 EC): 1.5 pt/A; PHI 5d, REI 12h or 72h for workers detasseling corn, Bee: H, Group 1B. Begin treatment when 10% of ears show silk. Apply when nymphs are young. Injury may occur in the whorl and silk stages using this type of malathion product.
zeta-cypermethrin (Mustang*): 2.24 to 4 oz/A; PHI 3d, REI 12h, Bee: H, Group 3A. Adults only.

Seedcorn Maggot (Delia platura)

See seedcorn maggot in the insect control section of Beans for more information about biology and management.

beta-cyfluthrin + tebuprimphos (Aztec* 2.1G): 6.7 oz/1000 row ft; REI 48h, Bee: H, Groups 3A and 1B. Must be incorporated into soil to at least 1" depth. Apply at planting as band or in-furrow.
bifenthrin (Capture* LFR): 3.4 to 6.8 oz/A for at-plant applications; 4 to 5.3 oz/A for pre-plant incorporation applications; PHI 1d, REI 12h, Bee: H, Group 3A. Apply as T-band over open furrow, in-furrow with the seed, or incorporated pre-planting to seed planting depth.
gamma-cyhalothrin (Declare*): 0.041 oz/1000 row ft for at-plant soil application; PHI 21d, REI 24h, Bee: H, Group 3A.
lambda-cyhalothrin (Warrior* II): 0.33 fl oz/1,000 ft as T-band or furrow application at planting; PHI 1d, REI 24h, Bee: H, Group 3A.
phorate (Thimet* 20-G): 4.5 to 6 oz/1,000 row ft; PHI 30d, REI 48h, Bee: H, Group 1B. Apply in a 7" band over the row at planting and lightly incorporate. Granules must be incorporated into the soil. DO NOT use in-furrow.
tefluthrin (Force* CS): 0.46 to 0.57 oz/1000 row feet; REI 48h, Bee: H, Group 3A. For T-banded or in-furrow applications at planting.
terbufos (Counter* 20G): 4.5 to 6 oz/1,000 row feet; REI 48h, Bee: M, Group 1B. Place granules in seed furrow behind planter shoe or in a 4-5" band over the row, and lightly incorporate.
thiamethoxam (Cruiser 5FS): 1.28 to 5.1 fl oz/100 lb of seed; REI 12h, Bee: H, Group 4A. Systemic seed treatment. Use standard slurry seed treatment equipment to ensure uniform coverage of kernels. For early-season protection from seedcorn maggot.

Stalk Borer (Papaipema nebris)

Stalk borer (also known as common stalk borer) is an occasional pest of corn and of other vegetable crops. It is the egg stage that overwinters, on grassy weeds where adult moths deposited them in the fall. Upon hatching in the spring, the caterpillars feed on grasses by boring into and along the stalk. When the caterpillars become too large to feed within the grass, they migrate to nearby thicker-stemmed wild and cultivated plants. In corn, infestations are heaviest in border rows and in fields with grassy weeds. Borers feed in the stalk or deep in the whorl, which may kill the growing tip. Larvae are brown to purplish brown with a broad white stripe on the back and each side. These stripes are interrupted by a distinctive, large brown spot around the whole body. Pupation occurs in the soil in late summer, with adult emergence and activity from August to October. There is one generation per year. Reduced tillage fields, which may have higher levels of grassy and broad-leaf weeds, may result in increased levels of stalk borer. To reduce overwintering eggs, prevent or eliminate grassy weeds, especially after July. Destroy weeds and grasses at field margins to reduce invasions at field borders. Scout for injury soon after the corn emerges in the spring and treat infested corn as needed. Apply insecticides to outer rows at the first sign of damage by this pest. Treat small larvae before they bore into stalks.

beta-cyfluthrin (Baythroid* XL): 1.6 to 2.8 oz/A; PHI 0d, REI 12h, Bee: H, Group 3A. Application must be made prior to larva boring into the plant.
chlorantraniliprole & lambda-cyhalothrin (Besiege*): 6 to 10 oz/A; PHI 1d, REI 24h, Bee: H, Groups 28 & 3A.
Chromobacterium subtsugae strain PRAA4-1 (Grandevo^OG): 1 to 3 lb/A; PHI 0d, REI 4h, Bee: M, Group UN.
deltamethrin (Delta Gold*): 1.5 to 2.4 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A. Apply to early instar larvae prior to boring into ear or stalk.
esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.
gamma-cyhalothrin (Declare*): 1.02 to 1.54 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A. For control before larvae bore into plant stalk or ear.
lambda-cyhalothrin (Warrior* II): 1.28 to 1.92 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A.
permethrin (Pounce* 25WP): 6.4 to 12.8 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.

Western bean cutworm (Striacosta albicosta)

Western bean cutworm is a late-season pest of corn that causes direct physical damage to corn and leaves plants more susceptible to pathogens. WBC is native to the US corn belt and has been moving eastward since the early 2000s. WBC has one generation per year. Adults begin emerging in June, with peak flight occurring from July through early August. Egg-laying and plant damage occurs August-October.

Adults look similar to other cutworm moths and corn pests but can be distinguished by a long white stripe that runs along the edge of the forewings. Other diagnostic characteristics include a small white dot in the middle of the forewing and a larger U-shaped brown dot further back on the forewing. Adults also have long antennae (1/3 to ½ length of the body). Adult moths are active at night.

Larvae also look similar to other caterpillar corn pests, but the most prominent difference is two dark brown rectangles directly behind the brown head capsule and a lack of black netting on head capsule.

Females lay about 50 white eggs in masses on upper surfaces of corn leaves prior to tasseling. The eggs turn purple about 24 hours before hatching. The caterpillars are very mobile and undergo 6 instars in a month before dropping to the soil to overwinter in a prepupal stage and then pupate in the spring. The 1st-3rd instars of WBC feed on leaf axils, pollen and corn silks, then bore into the ear during the 4th instar where they continue feeding on kernels.

Pheromone traps can be used to monitor adult activity. It’s best to scout corn tassels prior to pollen shed and upper leaf surfaces of new leaves for egg masses. Emergence holes from larvae that bored into ears can be seed in dry husks after harvest. There is also a NEWA model for WBC to help with timing of insecticide applications around moth activity and when to scout for egg masses and newly hatched larvae. Sprays will be ineffective once larvae bore into ears. Treatment is usually recommended when 95% of corn has tassels and 70-90% of egg masses have hatched

beta-cyfluthrin (Baythroid* XL): 1.6 to 2.8 oz/A; PHI 0d, REI 12h, Bee: H, Group 3A.
Burkholderia spp. Strain A396 cells and spent fermentation media (Venerate XC^OG): 1 to 4 qt/A; PHI 1d, REI 12h, Bee: H, Group UN.
chlorantraniliprole + lambda-cyhalothrin (Beseige*): 6 to 10 oz/A; PHI 1d, REI 24h, Bee: H, Group 28 & 3A.
gamma-cyhalothrin (Declare*): 1.02 to 1.54 oz/A; PHI 1d, REI 24h, Bee: H, Group 3A.
methoxyfenozide (Intrepid 2F): 4 to 16 fl oz/A; PHI 3d, REI 4h, Bee: L, Group 18. Apply at first sign of feeding damage.
methoxyfenozide + spinetoram (Intrepid Edge): 4 to 12 fl oz/A; PHI 3d, REI 4h, Bee: M, Group 18 & 5. Apply at first sign of feeding damage.

Wireworms and White Grub

See wireworms in the insect control section of Potato for more information. To avoid wireworm problems, corn should not be grown in rotation with sod or grass crops. Delay planting susceptible crops, such as corn or potatoes, on such land for at least two years after the sod has been broken. Summer fallow is recommended for at least one season.

Land that was in sod or pasture should be planted to legumes, such as alfalfa or clover, for a year or more before planting corn or other vegetables to reduce the number of white grubs in the soil. Plow or harrow in mid-summer, after harvesting early corn, to reduce grub numbers.

beta-cyfluthrin + tebuprimphos (Aztec* 2.1G): 6.7 oz/1000 row ft; REI 48h, Bee: H, Groups 3A and 1B. Must be incorporated into soil to at least 1" depth. Apply at planting as band or in-furrow.
bifenthrin (Capture* LFR): 3.4 to 13.6 oz/A for at-plant applications; 4 to 5.3 oz/A for pre-plant incorporation applications; PHI 2d, REI 12h, Bee: H, Group 3A. Apply as T-band over open furrow, in-furrow with the seed, or incorporated pre-planting to seed planting depth.
ethoprop (Mocap* 15%G): 8 oz/1,000 row feet; REI 48h, Bee: H, Group 1B. Apply as 6" to 7" band over closed seed furrow at-planting, then incorporate immediately into top 0.5" of soil. Suppression only for white grubs. Extremely toxic to birds. Do not leave granules on soil surface.
gamma-cyhalothrin (Declare*): 0.041 to 0.82 oz/1000 row ft for at-plant soil application, 0.26 oz/1000 row ft permitted for at-plant soil application in New Hampshire only; PHI 21d, REI 24h, Bee: H, Group 3A. Suppression only for wireworms. For white grub control in CT, ME, MA, RI and VT: use for reducing damage when used as T-band or in-furrow on light to moderate infestations. Use 0.14 to 0.18 oz/1000 row ft for moderate infestations. For high infestations, use a premium soil insecticide.
lambda-cyhalothrin (Warrior* II): 0.33 fl oz/1,000 ft. as T-band or furrow application at planting; PHI 1d, REI 24h, Bee: H, Group 3A.
phorate (Thimet* 20-G): 4.5 to 6 oz/1,000 row feet; PHI 30d, REI 48h, Bee: H, Group 1B. Apply in a 7" band over the row at planting and lightly incorporate. granules must be incorporated into the soil. DO NOT use in-furrow.
tefluthrin (Force* CS): 0.46 to 0.57 oz/1000 row feet; REI 48h, Bee: H, Group 3A. For T-banded or in-furrow applications. Use high rate for heavy infestations. For best control, apply as in-furrow.
terbufos (Counter* 20G): 4.5 to 6 oz/1,000 row feet; REI 48h, Bee: M, Group 1B. Place granules in seed furrow behind planter shoe or in a 4-5" band over the row, and lightly incorporate.
thiamethoxam (Cruiser 5FS): 1.28 to 5.1 fl oz/100 lb of seed; REI 12h, Bee: H, Group 4A. Systemic seed treatment. Use standard slurry seed treatment equipment to ensure uniform coverage of kernels. For early-season protection from wireworms and white grub (including Japanese beetle larvae, European chafer larvae, true white grub, annual white grub, May/June beetle larvae).

Insect Control