Insect Control

Aphids

Several species of aphids may probe, feed, and cause direct damage or transmit disease in dry or snap beans: soybean aphid, bean aphid, pea aphid, yellow clover aphid, and green peach aphid. Soybean aphid (Aphis glycines) reproduces in soybeans but not green or dry beans; however, this species can colonize, inflict feeding injury, and transmit viruses to green and dry beans. Soybean aphid is found on beans in New York and the Midwest, with higher pressure in hot, dry summers. This species has been less important in New England but could increase in importance, especially in soybean production areas. The other listed aphid species are all present in New England. Although aphids can spread viral diseases, using insecticides to control aphids is not effective in controlling these viruses. Generally, natural enemies keep aphids from reaching economic damage thresholds in beans. Scout for aphids on the undersides of leaves or terminal shoots. Treat only if aphids are well distributed throughout the field (50% or more of terminals with 5 or more aphids), natural enemies are lacking, and the population is increasing. Use selective products for other pests to conserve natural enemies of aphids and to protect bees. Systemic insecticide may be used as a seed treatment or at planting. Avoid planting beans near alfalfa or soybean. See the Pepper insect control section for more information on green peach aphid.

IRAC Group 1:

• acephate (Orthene 97): 0.5 to 1 lb/A; PHI 14d, REI 24h, Bee: H, Group 1B. Use on succulent green beans prohibited, except those grown for seed. Not for black bean aphid. 
• dimethoate (Dimethoate 4EC): 0.5 to 1 pt/A; PHI 0d, REI 48h, Bee: H, Group 1B. Not for cowpeas. 
• methomyl (Lannate* LV): 1.5 to 3 pt/A; PHI 1d fresh at up to 1.5 pt/A, 3d for over 1.5 pt/A, 14 d dry; REI 48h, Bee: H, Group 1A.

IRAC Group 3:

• alpha-cypermethrin (Fastac* CS): 3.2 to 3.9 oz/A; PHI 1d fresh, 21d dry; REI 12h, Bee: H. See resistance statement on label. Aphid control may be variable depending on species present and host-plant relationships. 
• bifenthrin (Brigade* 2EC): 2.1 to 6.4 oz/A; PHI 3d, REI 12h, Bee: H. 
• esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 3d fresh, 21d dry; REI 12h, Bee: H. For pea aphid only.
• gamma-cyhalothrin (Declare*): 1.02 to 1.54 oz/A; PHI 7d fresh, 21d dry, REI 48h, Bee: H. See resistance statement on label. 
• lambda-cyhalothrin (Warrior* II): 1.28 to 1.92 oz/A; PHI 7d fresh, 21d dry, REI 24h, Bee: H. See resistance statement on label. 
• pyrethrin (PyGanic EC5.0^OG): 4.5 to 15.61 oz/A, or 0.25 to 0.50 oz/gal and 3 gal/1000 sq ft in greenhouse for backpack sprayers; PHI 0d, REI 12h, Bee: M.

IRAC Group 4:

• acetamiprid (Assail 30SG): 2.5 to 5.3 oz/A; PHI 7d, REI 12h, Bee: M, Group 4A. Edible-podded and succulent shelled peas and beans only.
• flupyradifurone (Sivanto): 7 to 14 oz/A; PHI 7d, REI 4h, Bee: L, Group 4D.
• imidacloprid (Admire Pro): 7 to 10.5 oz/A soil, 1.2 oz/A foliar; PHI 21d soil, 7d foliar, REI 12h, Bee: H, Group 4A.
• sulfoxaflor (Transform WG): 0.75 to 1 oz/A; PHI 7d, REI 24h, Bee: H, Group 4C. 
• thiamethoxam (Cruiser 5FS): 1.28 oz/100 lb of seed; REI 12h, Bee: H, Group 4A. Systemic seed treatment. For early-season protection from aphids. 

IRAC Group 8:

• sodium tetraborohydrate decahydrate (Prev-AM): 100 oz/100 gal; REI 24h, Bee: L, Group 8D. Do not apply in midday sun or mix with copper.

IRAC Group 29:

• flonicamid (Beleaf 50SG): 2.8 oz/A; PHI 7d, REI 12h, Bee: L.

IRAC Group UN:

• Chromobacterium subtsugae strain PRAA4-1 (Grandevo^OG): 2 to 3 lb/A; PHI 0d, REI 4h, Bee: M.
• Isaria fumosorosea Apopka Strain 97 (PFR-97 20% WDG^OG): 1 to 2 lb/A foliar; PHI 0d, REI 4h, Bee: M.
• mineral oil (SuffOil-X^OG): 1 to 2 gal/100 gal water; PHI 0d, REI 4h, Bee: L. Apply as needed. 

Cutworms

Cutworm larvae may be dull gray, brown, or black and may be striped or spotted, depending on the species. They will roll into a tight C-shape if disturbed. The two most common species are the variegated cutworm (Peridroma saucia), which feeds on lower leaves and petioles, and the black cutworm (Agrotis ipsilon), which largely feeds at the soil surface or below on roots and lower stems. The black cutworm will occasionally feed on leaves. Both are nocturnal feeders and take refuge under the soil surface during the day. Cutworms find weedy or minimum-tillage fields especially attractive sites to lay their eggs. Seedlings are most affected; look for cut stems or foliage feeding. Scout across the field, as injury may be limited to a few small areas. Control is warranted if overall plant stand or survival is threatened. For best results, make insecticide applications between midnight and dawn while cutworms are feeding aboveground. See the Pepper and Tomato (Outdoor) insect control sections for more information on black and variegated cutworms.

IRAC Group 1:

• acephate (Orthene 97): 0.5 to 1 lb/A; PHI 14d, REI 24h, Bee: H, Group 1B. Use on succulent green beans prohibited, except those grown for seed. 
• carbaryl (Sevin XLR Plus): 1 to 1.5 qt/A; PHI 3d fresh, 21d dry; REI 12h, Bee: H, Group 1A. Do not apply to crops or weeds in bloom. Not for succulent and shelled beans.

IRAC Group 3:

• alpha-cypermethrin (Fastac* CS): 1.3 to 3.8 oz/A; PHI 1d fresh, 21d dry, REI 12h, Bee: H.
• bifenthrin (Brigade* 2EC): 2.1 to 6.4 oz/A; PHI 3d, REI 12h, Bee: H. 
• esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 3d fresh, 21d dry; REI 12h, Bee: H. On snap beans, use only as a seedling spray. 
• lambda-cyhalothrin (Warrior* II): 0.96 to 1.60 oz/A; PHI 7d fresh, 21d dry; REI 24h, Bee: H.
• lambda-cyhalothrin +  chlorantraniliprole (Besiege*): 5 to 8 oz/A; PHI 7d fresh, 21d dry; REI 24h, Bee: H, Groups 3A & 28.
• zeta-cypermethrin (Mustang* Maxx): 1.28 to 4 oz/A, 4 oz/A at planting for dry beans; PHI 1d fresh, 21d dry, REI 12h, Bee: H.

IRAC Group 5:

• spinosad (Seduce^OG): 20 to 44 lb/A or 0.5 to1 lb/1000 sq ft; PHI 3d fresh, 28d dry; REI 4h, Bee: M. Spread bait on soil around plants.

IRAC Group 28:

• chlorantraniliprole + lambda-cyhalothrin (Besiege*): 5 to 8 oz/A; PHI 7d fresh, 21d dry; REI 24h, Bee: H, Groups 28 & 3A.

European Corn Borer (Ostrinia nubilalis), Corn Earworm (Helicoverpa zea), and Cabbage Looper (Trichoplusia ni)

These caterpillars are occasional pests of beans in New England. See the Sweet Corn insect control section for more details on European corn borer (ECB) and corn earworm (CEW), and the Cabbage, Broccoli, Cauliflower, and Other Brassica Crops insect section for more information on cabbage looper (CL).

In beans, ECB eggs are laid under leaves, and larvae feed in stems then bore into pods. If a preferred host, such as corn, is not available, eggs will be laid in beans. This may occur where early beans are planted after a corn crop the previous year, or where late beans are near a maturing corn crop at the emergence of the second ECB generation. The most susceptible period in snap beans is from the bud stage (about 26 days before harvest) to pod formation (12 days before harvest), and in dry beans is for the 4 weeks preceding the onset of pod drying. Infestation depends on the synchrony of ECB flight and bean stage. The most effective timing for a single insecticide application is at bloom or pod formation. The most practical and effective control for ECB is to avoid planting early beans where corn was grown the previous year or late beans near corn where ECB may emerge. Monitor moth activity in corn using pheromone traps or refer to pest alert networks to detect peak or high flights. Scout if flights are high during the susceptible period of bean growth, looking for wilted or chewed trifoliate leaves, larvae, or pod injury. There is no set threshold for treatment.

CEW or CL may lay eggs in beans when migratory flights result in very high populations. CEW or CL caterpillars feed on leaves, buds, flowers, and pods, often damaging the beans. CEW and CL feeding holes may be larger than ECB entry holes. The impact of these caterpillars on overall plant growth and yield is minimal, but the tolerance for caterpillar infestation is extremely low in processing beans where larval contamination must be avoided.

IRAC Group 1:

• acephate (Orthene 97): 0.5 to 1 lb/A CL; 0.75 to 1 lb/A ECB and CEW; PHI 14d, REI 24h, Bee: H, Group 1B. Use on succulent green beans prohibited, except those grown for seed.
• carbaryl (Sevin XLR Plus): 0.5 to 1.5 qt/A CEW, 1 to 1.5 qt/A ECB; PHI 3d fresh, 21d dry; REI 12h, Bee: H, Group 1A. Do not apply to crops or weeds in bloom. Not for CL. Not for succulent and shelled beans.
• methomyl (Lannate* LV): 1.5 to 3 pt/A; PHI 1d fresh at up to 1.5 pt/A, 3d for over 1.5 pt/A, 14d dry; REI 48h, Bee: H, Group 1A. Ovicide and larvicide for ECB.

IRAC Group 3:

• alpha-cypermethrin (Fastac* CS): 2.7 to 3.8 oz/A ECB and CEW, 3.2 to 3.9 oz/A CL; PHI 1d fresh, 21d dry: REI 12h, Bee: H. See resistance statement on label for CL. 
• bifenthrin (Brigade* 2EC): 2.1 to 6.4 oz/A; PHI 3d, REI 12h, Bee: H. 
• esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 3d fresh, 21d dry; REI 12h, Bee: H. Not for ECB on dry beans.
• gamma-cyhalothrin (Declare*): 1.02 to 1.54 oz/A; PHI 7d fresh, 21d dry; REI 48h, Bee: H. For control before ECB larvae bore into the plant stalk or pods. 
• lambda-cyhalothrin (Warrior* II): 1.28 to 1.92 oz/A; PHI 7d fresh, 21d dry; REI 24h, Bee: H.
• lambda-cyhalothrin + chlorantraniliprole (Besiege*): 6 to 10 oz/A; PHI 7d fresh, 21d dry, REI 24h, Bee: H, Groups 28 & 3A.
• pyrethrin (PyGanic EC5.0^OG): 4.5 to 15.61 oz/A, or 0.25 to 0.50 oz/gal and 3 gal/1000 sq ft in greenhouse for backpack sprayers; PHI 0d, REI 12h, Bee: M. Not for ECB.
• zeta-cypermethrin (Mustang* Maxx): 2.72 to 4 oz/A ECB and CEW, 3.2 to 4 oz/A CL; PHI 1d fresh, 21d dry; REI 12h, Bee: H. See resistance statement on label for CL. 

IRAC Group 5:

• spinosad (Entrust SC^OG): 3 to 6 oz/A ECB eggs and larvae, 4 to 6 oz/A CEW and looper; PHI 3d fresh, 28d dry, REI 4h, Bee: M.

IRAC Group 11:

• Bacillus thuringiensis aizawai (XenTari^OG): 0.5 to 1.5 lb/A; PHI 0d, REI 4h, Bee: L. Must be ingested. For resistance management, may be rotated with Bt kurstaki products (Dipel). CL only.
• Bacillus thuringiensis kurstaki (Dipel DF^OG): 0.5 to 2 lb/A; PHI 0d, REI 4h, Bee: L. Must be ingested. For resistance management, may be rotated with Bt aizawai products (XenTari, CLonly).

IRAC Group 18:

• methoxyfenozide (Intrepid 2F): For ECB and CL, 4 to 8 oz/A early season on young plants, 8 to 16 oz/A for mid- to late-season; For CEW, 10 to 16 oz/A; PHI 7d, REI 4h, Bee: L. Suppression only for CEW.

IRAC Group 28:

• chlorantraniliprole (Coragen): 5 to 7.5 oz/A soil at planting, 3.5 to 7.5 oz/A foliar; PHI 1d, REI 4h, Bee: L. Foliar applications only for CL. 
• chlorantraniliprole + lambda-cyhalothrin (Besiege*): 6 to 10 oz/A; PHI 7d fresh, 21d dry, REI 24h, Bee: H, Groups 28 & 3A.

IRAC Group UN:

• Chromobacterium subtsugae strain PRAA4-1 (Grandevo^OG): 1 to 3 lb/A; PHI 0d, REI 4h, Bee: M. CEW and CL only.

Garden Springtails (Bourletiella hortensis)

Springtails are tiny (1/16") blue-grey, tan, or yellow insects that appear to jump like fleas when disturbed. These insects are important for decomposing dead plant matter. Occasionally, especially in dry conditions, high populations feed on the leaves of seedlings, producing tiny pits in the leaf surfaces that resemble flea beetle damage. In rare cases, affected plants may die of excessive water loss. Populations can be extreme in high organic matter fields, reduced-till systems, and soils that crack when drying. Use clean cultivation and spot-treat areas where damage occurs. Most broad-spectrum insecticides registered for cutworms or leafhoppers will also control springtails.

Japanese Beetles (Popillia japonica)

Beetles migrate from turf or pastures starting in July and skeletonize leaves.

IRAC Group 3: 

• bifenthrin (Brigade* 2EC): 2.1 to 6.4 oz/A; PHI 3d, REI 12h, Bee: H. Adults only on dry beans.
• pyrethrin (PyGanic EC5.0^OG): 4.5 to 15.61 oz/A, or 0.25 to 0.50 oz/gal and 3 gal/1000 sq ft in greenhouse for backpack sprayers; PHI 0d, REI 12h, Bee: M.

IRAC Group UN:

• Isaria fumosorosea Apopka Strain 97 (PFR-97 20% WDG^OG): 1 to 2 lb/A soil only; PHI 0d, REI 4h, Bee: M.

Mexican Bean Beetle (Epilachna varivestis)

Mexican bean beetles (MBB) most often grow to damaging populations where snap beans are grown in the same or adjacent fields over successive years. Lima beans and dry beans are also susceptible, and MBB may feed in dry and edible-pod soybeans but are less likely to thrive on these hosts. Adults are copper-colored, oval ladybeetles,  1/4"–1/3" long, with black spots. Eggs are orange to yellow in color and are laid on the underside of leaves in clusters of 40 to 50. Larvae are yellow with rows of branched, black-tipped spines. The pupa is attached to the leaf, has less pronounced spikes and is yellow to yellow-orange. Adults spend the winter in hedgerows and move into fields in June. Adults and larvae skeletonize leaves and may cause pod damage if numbers are high. There are 1–3 generations per year in New England, with newly emerging adults moving to the next succession planting of snap beans. A life cycle may be completed in 30–40 days during the summer. Populations are usually less abundant on early plantings and may not build to damaging levels until August. Prompt destruction of crop residue after harvest helps lower overwintering populations. Avoid continuous production of beans in the same or adjacent fields year after year. Annual releases of the larval parasitoid Pediobius foveolatus, timed to coincide with egg hatch, can help control beetle larvae. The wasp will not survive our winters, so it must be re-released each year, but it reproduces throughout the summer and moves into later plantings. Parasitized larvae serve as pupal cases for the wasp, remaining on the leaf and turning brown. Scout for MBB by searching plants for adults, eggs, and larvae, and assessing damage. Treat when defoliation exceeds 20% pre-bloom or 10% during pod development. The presence of adults, eggs, and larvae indicates the potential for further damage. Be sure to get coverage of the lower leaf surfaces. 

IRAC Group 1:

• acephate (Orthene 97): 0.5 to 1 lb/A; PHI 14d, REI 24h, Bee: H, Group 1B. Use on succulent green beans prohibited, except those grown for seed. 
• carbaryl (Sevin XLR Plus): 0.5 to 1 qt/A; PHI 3d fresh, 21d dry; REI 12h, Bee: H, Group 1A. Do not apply to crops or weeds in bloom. Not for succulent and shelled beans.
• dimethoate (Dimethoate 4EC): 0.5 to 1 pt/A; PHI 0d, REI 48h, Bee: H, Group 1B.
• methomyl (Lannate* LV): 0.75 to 3 pt/A; PHI 1d fresh at up to 1.5 pt/A, 3d for over 1.5 pt/A, 14d dry; REI 48h, Bee: H, Group 1A.

IRAC Group 3:

• alpha-cypermethrin (Fastac* CS): 2.7 to 3.8 oz/A; PHI 1d fresh, 21d dry; REI 12h, Bee: H.
• esfenvalerate (Asana* XL): 2.9 to 5.8 oz/A; PHI 3d fresh, 21d dry; REI 12h, Bee: H.
• lambda-cyhalothrin (Warrior* II): 0.96 to 1.60 oz/A; PHI 7d fresh, 21d dry; REI 24h, Bee: H.
• lambda-cyhalothrin + chlorantraniliprole (Besiege*): 5 to 8 oz/A; PHI 7d fresh, 21d dry; REI 24h, Bee: H, Groups 3A & 28.
• pyrethrin (PyGanic EC5.0^OG): 4.5 to 15.61 oz/A, or 0.25 to 0.50 oz/gal and 3 gal/1000 sq ft in greenhouse for backpack sprayers; PHI 0d, REI 12h, Bee: M.
• zeta-cypermethrin (Mustang* Maxx): 2.72 to 4 oz/A; PHI 1d fresh, 21d dry; REI 12h, Bee: H. 

IRAC Group 4:

• acetamiprid (Assail 30SG): 2.5 to 5.3 oz/A; PHI 7d, REI 12h, Bee: M, Group 4A. Edible-podded and succulent shelled peas and beans only.
• thiamethoxam (Cruiser 5FS): 1.28 oz/100 lb of seed; REI 12h, Bee: H, Group 4A. Systemic seed treatment. For early-season protection.

IRAC Group 28:

• chlorantraniliprole + lambda-cyhalothrin (Besiege*): 5 to 8 oz/A; PHI 7d fresh, 21d dry; REI 24h, Bee: H, Groups 28 & 3A.

IRAC Group UN:

• kaolin (Surround WP^OG): 25 to 50 lb/A or 0.25 to 0.5 lb/gal; PHI 0d, REI 4h, Bee: L. Suppression only. If complete control is needed, consider using supplemental controls.
• mineral oil (SuffOil-X^OG): 1 to 2 gal/100 gal water; PHI 0d, REI 4h, Bee: L. For beetle larvae only.

Potato Leafhopper (Empoasca fabae)

Adults are light yellow-green, 1/8" long, and wedge-shaped (wider at the head), while nymphs are bright green, flatter and wider than adults, and move sideways in a crab-like fashion. Adults lay eggs on stems, where nymphs hatch, feed, and pass through five instars before becoming adults. The presence of nymphs indicates an established population. Potato leafhoppers (PLH) overwinter in Gulf states and move north with storm fronts into the central states, then into New England on winds from the west. Arrival time varies with year and location, ranging from late May to late June. Low levels of leafhopper feeding can severely damage plants, especially at the seedling stage. Both adults and nymphs cause injury by injecting a toxin as they feed through piercing-sucking mouthparts. Signs of injury begin with leaf veins turning pale, followed by yellowing or browning of areas of the leaf or leaf tips, known as "hopperburn". Leaves become brown, curl up, and die. Plants and roots may be stunted and yields reduced or lost. This process may take less than a week. PLH may also vector many viruses. Scout using a sweep net or by observing adults flying when plants are shaken. Nymphs can be counted on the undersides of leaves. Seedling beans should be treated if they have 2 adults per foot of row. From the third trifoliate leaf to the bud stage, treat when PLH exceeds 1 nymph/leaflet or 5 adults per foot of row, and repeat application in 7-10 days, if necessary. Be sure to treat lower leaf surfaces. In fields where a systemic seed treatment (e.g., Cruiser) was used, foliar treatment should not be needed before bloom.

IRAC Group 1:

• acephate (Orthene 97): 0.5 to 1 lb/A; PHI 14d, REI 24h, Bee: H, Group 1B. Use on succulent green beans prohibited, except those grown for seed. 
• carbaryl (Sevin XLR Plus): 1 qt/A; PHI 3d fresh, 21d dry; REI 12h, Bee: H, Group 1A. Do not apply to crops or weeds in bloom. Not for succulent and shelled beans.
• dimethoate (Dimethoate 4EC): 0.5 to 1 pt/A; PHI 0d, REI 48h, Bee: H, Group 1B. Not for cowpeas.
• methomyl (Lannate* LV): 0.75 to 3 pt/A; PHI 1d fresh at up to 1.5 pt/A, 3d for over 1.5 pt/A, 14d dry; REI 48h, Bee: H, Group 1A.

IRAC Group 3:

• alpha-cypermethrin (Fastac* CS): 2.7 to 3.8 oz/A; PHI 1d fresh, 21d dry, REI 12h, Bee: H.
• bifenthrin (Brigade* 2EC): 1.6 to 6.4 oz/A; PHI 3d, REI 12h, Bee: H. 
• esfenvalerate (Asana* XL): 5.8 to 9.6 oz/A; PHI 3d fresh, 21d dry, REI 12h, Bee: H.
• gamma-cyhalothrin (Declare*): 1.02 to 1.54 oz/A; PHI 7d fresh, 21d dry, REI 48h, Bee: H.
• lambda-cyhalothrin (Warrior* II): 1.28 to 1.92 oz/A; PHI 7d fresh, 21d dry, REI 24h, Bee: H.
• lambda-cyhalothrin + chlorantraniliprole (Besiege*): 6 to 10 oz/A; PHI 7d fresh, 21d dry, REI 24h, Bee: H, Groups 3A & 28.
• pyrethrin (PyGanic EC5.0^OG): 4.5 to 15.61 oz/A, or 0.25 to 0.50 oz/gal and 3 gal/1000 sq ft in greenhouse for backpack sprayers; PHI 0d, REI 12h, Bee: M.
• zeta-cypermethrin (Mustang* Maxx): 2.72 to 4 oz/A; PHI 1d fresh, 21d dry, REI 12h, Bee: H.

IRAC Group 4: 

• acetamiprid (Assail 30SG): 2.5 to 5.3 oz/A; PHI 7d, REI 12h, Bee: M, Group 4A. Edible-podded and succulent shelled peas and beans only.
• flupyradifurone (Sivanto): 7 to 14 oz/A; PHI 7d, REI 4h, Bee: L, Group 4D.
• imidacloprid (Admire Pro): 7 to 10.5 oz/A soil, 1.2 oz/A foliar; PHI 21d soil, 7d foliar; REI 12h, Bee: H, Group 4A.
• thiamethoxam (Cruiser 5FS): 1.28 oz/100 lb of seed; REI 12h, Bee: H, Group 4A. Systemic seed treatment. For early-season protection.

IRAC Group 28:

• chlorantraniliprole + lambda-cyhalothrin (Besiege*): 6 to 10 oz/A; PHI 7d fresh, 21d dry; REI 24h, Bee: H, Groups 28 & 3A.

IRAC Group UN:

• Chromobacterium subtsugae strain PRAA4-1 (Grandevo^OG): 2 to 3 lb/A; PHI 0d, REI 4h, Bee: M.
• kaolin (Surround WP^OG): 25 to 50 lb/A or 0.25 to 0.5 lb/gal; PH 0d, REI 4h, Bee: L. Suppression only. If complete control is needed, consider using supplemental controls. 
• mineral oil (SuffOil-X^OG): 1 to 2 gal/100 gal water; PHI 0d, REI 4h, Bee: L. Apply as needed.
• paraffinic oil (Organic JMS Stylet-Oil^OG): 3 to 6 qt/100 gal water; PHI 0d, REI 4h, Bee: L.

Seedcorn Maggot (Delia platura)

Seedcorn maggot larvae feed on the seeds and early seedlings of large-seeded crops such as corn, beans, and peas as well as early seedlings of spinach, onions, brassicas, tomato, cucurbits, and other crops. They are the first maggot flies to become active in spring, about 1–2 weeks earlier than onion or cabbage maggot. The adults look like small, gray houseflies with a slightly hump-backed shape. The seedcorn maggot larva is yellow-white, up to 1/4" long, legless, and has a wedge-shaped head. Pupae are oblong, brown, and about 4–5 mm long. The seedcorn maggot fly overwinters in the pupal stage, in the soil where they feed in the fall. In early spring, the adults emerge and lay eggs on the soil surface. Growing degree days, using a base temperature of 39°F (4°C), can be used to predict peak emergence of the first generation (360ºF or 200ºC GDD). Flies are attracted to volatiles released from freshly tilled soil, as well as to buried cover crop residues, rotting manure, compost, organic surface residues (as found in reduced-till systems), and organic amendments such as fish, soybean, or cottonseed meal. Previously injured or diseased plants may also attract egg-laying. The eggs hatch within 2–4 days at soil temperatures of 60°F and 7–9 days at 41°F–45°F. Larvae burrow downward in search of food and penetrate seeds as the seed coat splits open. Though there are 2–4 generations per year, it is the first generation that causes the most damage. The first symptoms are usually poor emergence of seeds or wilting of transplants that have lost their roots to feeding. Look for maggots and feeding tunnels inside seeds or stems to help distinguish damage from wireworm feeding or damping-off. Crops that are planted in wet soil, or soil that is too cool to support quick germination and seedling growth, are especially susceptible to damage. Wait until soil conditions favor crop emergence and growth to help seeds and seedlings avoid or quickly recover from injury. Plant shallowly to promote rapid emergence. Where possible, incorporate cover crops, manure, or compost several weeks before seeding. Put earliest plantings in lighter, well-drained, sandy soils that warm up quickly. Among bean varieties, those with a dark seed coat sustain less injury than white varieties. Use row covers to exclude flies, except where flies may have fed in fall cover or vegetable crops and could emerge under the covers. Preventive chemical treatments include commercially applied systemic seed treatments and in-furrow applications of insecticides. Rescue treatments are not effective. If there is enough damage to warrant replanting, wait at least 5 days if maggots are 1/4" long; if they are smaller than that, wait at least 10 days to make sure they have pupated and will not damage the new seeds.

IRAC Group 1:

• phorate (Thimet* 20-G): 4.5 to 7 oz/1000 ft of row for any plant spacing; PHI 60d, REI 48h, Bee: H, Group 1B. At planting treatment. DO NOT place granules in direct contact with seed. Granules must be incorporated into the soil. Do not feed treated crop residue to livestock. Do not apply more than once per season.

IRAC Group 4:

• thiamethoxam (Cruiser 5FS): 1.28 oz/100 lb of seed; REI 12h, Bee: H, Group 4A. Systemic seed treatment. For early-season protection.

Slugs

Damage appears as shredded foliage or holes in fruit. Look for silvery slime trails on leaves or turn over soil clods or debris to find slugs during daylight hours. Grow plants away from moist, shaded habitats, use clean cultivation, control weeds, hand pick or crush slugs, or scatter baits on the ground near infested plants. See the Cabbage, Broccoli, Cauliflower, and other Brassica Crops insect control section for more information on slugs.

IRAC Group UN:

• iron phosphate (Sluggo: Slug and Snail Bait^OG): 20 to 44 lb/A; PHI 0d, REI 0h, Bee: L. Apply around perimeter, scatter around base of plants, or band down rows. Apply to moist soil in the evening.

Tarnished Plant Bug (Lygus lineolaris)

See the Lettuce, Endive, and Escarole insect control section for information about tarnished plant bug.

IRAC Group 1:

• acephate (Orthene 97): 0.5 to 1 lb/A; PHI 14d, REI 24h, Bee: H, Group 1B. Use on succulent green beans prohibited, except those grown for seed.
• carbaryl (Sevin XLR Plus): 1 to 1.5 qt/A; PHI 3d fresh, 21d dry, REI 12h, Bee: H, Group 1A. Do not apply to crops or weeds in bloom. Not for succulent and shelled beans.
• methomyl (Lannate* LV): 1.5 to 3 pt/A; PHI 1d fresh at up to 1.5 pt/A, 3d for over 1.5 pt/A, 14d dry; REI 48h, Bee: H, Group 1A.

IRAC Group 3:

• alpha-cypermethrin (Fastac* CS): 2.7 to 3.8 oz/A; PHI 1d fresh, 21d dry; REI 12h, Bee: H.
• bifenthrin (Brigade* 2EC): 2.1 to 6.4 oz/A; PHI 3d, REI 12h, Bee: H. 
• lambda-cyhalothrin (Warrior* II): 1.28 to 1.92 oz/A; PHI 7d fresh, 21d dry; REI 24h, Bee: H. See resistance management statement on label.
• lambda-cyhalothrin + chlorantraniliprole (Besiege*): 6 to 10 oz/A; PHI 7d fresh, 21d dry; REI 24h, Bee: H, Groups 3A & 28.
• pyrethrin (PyGanic EC5.0^OG): 4.5 to 15.61 oz/A, or 0.25 to 0.50 oz/gal and 3 gal/1000 sq ft in greenhouse for backpack sprayers; PHI 0d, REI 12h, Bee: M.
• zeta-cypermethrin (Mustang* Maxx): 2.72 to 4 oz/A; PHI 1d fresh, 21d dry; REI 12h, Bee: H.

IRAC Group 4:

• sulfoxaflor (Transform WG): 1.5 to 2.25 oz/A; PHI 7d, REI 24h, Bee: H, Group 4C. 

IRAC Group 8:

• sodium tetraborohydrate decahydrate (Prev-AM): 100 oz/100 gal; REI 24h, Bee: L, Group 8D. Do not apply in midday sun or mix with copper.

IRAC Group 28:

• chlorantraniliprole + lambda-cyhalothrin (Besiege*): 6 to 10 oz/A; PHI 7d fresh, 21d dry; REI 24h, Bee: H, Groups 28 & 3A. See resistance management section on label. 

IRAC Group UN:

• Isaria fumosorosea Apopka Strain 97 (PFR-97 20% WDG^OG): 1 to 2 lb/A foliar; PHI 0d, REI 4h, Bee: M.

Two-spotted Spider Mite (Tetranychus urticae)

Outbreaks with two-spotted spider mite (TSSM), also known as red spider mite, are favored by hot, dry weather and may be triggered by the use of broad-spectrum insecticides that kill the numerous natural enemies of mites. TSSM affect dry, lima, and snap beans. Infestations begin on the lower portions of the plant and move upward. Watch for white speckling and bronzing on the upper surface of leaves (veins may remain green) and fine, grayish webbing on the undersurface around leaf veins. Use a 10X hand lens to see mites traveling along strands of webbing. Avoid early-season, broad-spectrum insecticide applications for other pests; use selective products whenever possible. Registered products for mites on beans may not provide complete control of the pest. With most miticides, make 2 applications approximately 5–7 days apart to help control immature mites that were in the egg stage and protected during the first application. Coverage of the lower surface of the leaves is important. If further applications are needed, switch to an alternate resistance group to help prevent or delay resistance. See the Eggplant insect control section for more information on TSSM.

IRAC Group 1:

• dimethoate (Dimethoate 4EC): 0.5 to 1 pt/A; PHI 0d, REI 48h, Bee: H, Group 1B. Not for cowpeas. 

IRAC Group 6:

• abamectin (Agri-Mek SC): 1.75 to 3.5 oz/A; PHI 7d, REI 12h, Bee: H. 

IRAC Group 8:

• sodium tetraborohydrate decahydrate (Prev-AM): 50 oz/100 gal; REI 24h, Bee: L, Group 8D. Do not apply in midday sun or mix with copper.

IRAC Group 20:

• acequinocyl (Kanemite 15SC): 31 oz/A; PHI 7d, REI 12h, Bee: L, Group 20B. Two-spotted spider mite only on edible podded beans. TSSM and broad mite control on dried shelled beans. 
• bifenazate (Acramite 50WS): 0.75 to 1 lb/A; PHI 3d, REI 12h, Bee: M, Group 20D. Not for dried beans. 

IRAC Group 21:

• fenpyroximate (Portal XLO): 2 pt/A; PHI 1d, REI 12h, Bee: L. Snap bean only. 

IRAC Group UN:

• mineral oil (SuffOil-X^OG): 1 to 2 gal/100 gal water; PHI 0d, REI 4h, Bee: L. Apply as needed. 
• neem oil (Trilogy^OG): 0.5% to 2% solution in 25 to 100 gal water/A; PHI 0d, REI 4h, Bee: M. 
• sulfur (Microthiol Disperss^OG): 3 to 10 lb/A; REI 24h, Bee: L. Labeled for red spider mite.