1. Insect
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  4. Hosts and Pests of Vegetable Crops

Pumpkin and squash-Cucumber beetle

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Image related to Pumpkin and squash-Cucumber beetle
Western spotted cucumber beetle
Diabrotica undecimpunctata undecimpunctata Mannerheim
Immature on host
© Ken Gray Insect Image Collection
Image related to Pumpkin and squash-Cucumber beetle
Western spotted cucumber beetle
Diabrotica undecimpunctata undecimpunctata Mannerheim
Adult female adult
© Ken Gray Insect Image Collection
Image related to Pumpkin and squash-Cucumber beetle
Western spotted cucumber beetle
Diabrotica undecimpunctata undecimpunctata Mannerheim
Egg(s) on host
© Ken Gray Insect Image Collection
Image related to Pumpkin and squash-Cucumber beetle
Western spotted cucumber beetle
Diabrotica undecimpunctata undecimpunctata Mannerheim
Adult female adult
© Ken Gray Insect Image Collection

Western spotted cucumber beetle (Diabrotica undecimpunctata)
Western striped cucumber beetle (Acalymma trivittatum)

Pest description and crop damage The western spotted cucumber beetle is yellowish green, 0.25 inch long, and has 11 black spots on its wing covers. Mature larvae are white except for the head and last abdominal segment, which are brown. They are about 0.62 inch long. A close relative, the western striped cucumber beetle, is yellowish and has three black lines down its back. The larvae live in the soil, where they feed on roots. Adults are foliage and flower feeders. Cucumber beetle adults eat small holes in the leaves and flowers of many crops. Larvae feed on roots and bore into the base of stems.

Biology and life history Cucumber beetles overwinter as fertilized adults and are active beginning in early spring. Adults lay eggs at the base of plants. Eggs hatch in 7 to 10 days, and larvae feed in roots for about 3 weeks before pupating in the soil. Adults emerge in 2 weeks and begin feeding on pollen. As soon as they hatch, larvae begin to feed on plant roots. They complete their development in the soil. It takes 30 to 60 days to complete a life cycle. There are two generations a year.

Pest monitoring Specific treatment thresholds have not been established for these foliage feeders. Late year infestations are insignificant. If damaging numbers are encountered mid year, excessive foliage loss may reduce crop production. To prevent cucumber beetle damage to seedlings, Virginia recommendation is to treat at one beetle per 10 row ft.

Management-cultural control

Commercial row crop covers provide good protection from cucumber beetles, and in addition provide late frost protection and help in moisture retention. Sometimes, the timing of a crop planting can be delayed until after beetles have dispersed and deposited most of their eggs. Delaying planting until warmer weather also gives crops a greater chance of outgrowing beetle injury. Trap crops sometimes can be used to draw beetles away from the main crop. Trap cropping is an unproven control method in Oregon.

Management-chemical control: HOME USE

  • acetamiprid
  • azadirachtin (neem oil)-Some formulations are OMRI-listed for organic use.
  • bifenthrin (usually as a mix with zeta-cypermethrin).
  • carbaryl
  • cyfluthrin
  • deltamethrin
  • esfenvalerate
  • imidacloprid
  • insecticidal soap-Some formulations OMRI-listed for organic use.
  • kaolin-Applied as a spray to foliage, it acts as a repellent to some insect pests. Some formulations are OMRI-listed for organic use.
  • malathion
  • permethrin
  • pyrethrins-Some formulations are OMRI-listed for organic use.
  • zeta-cypermethrin

Note: Pesticides can injure cucurbits. Be sure foliage is dry at time of application.

Management-chemical control: COMMERCIAL USE

  • acetamiprid (Assail 30SG) 0.047 to 0.1 lb ai/a. PHI 0 days. REI 12 hr. Retreatment interval 5 days. Do not exceed 5 applications or 0.5 lb ai/a per season.
  • alpha-cypermethrin (Fastac EC) at 0.0175 to 0.025 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.075 lb ai/a per season.
  • azadirachtin (Neemix 4.5)-See label for rates. Acts slowly; apply early. PHI 0 days. REI 4 hr. Thorough coverage and repeat applications are necessary. Some formulations are OMRI-listed for organic use.
  • beta-cyfluthrin (Baythroid XL) at 0.019 to 0.022 lb ai/a. PHI 0 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.088 lb ai/a per season.
  • bifenthrin (Brigade WSB) at 0.05 to 0.1 lb ai/a. PHI 3 days. REI 12 hr. Do not exceed 0.3 lb ai/a per season. Do not make more than two applications bloom. Retreatment interval 7 days.
  • bifenthrin/avermectin (Athena) at 0.05 to 0.12 lb ai/a. PHI 7 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.056 lb ai/a avermectin or 0.3 lb ai/a bifenthrin per season.
  • bifenthrin/zeta-cypermethrin (Hero EW) at 0.04 to 0.1 lb ai/a. PHI 3 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.4 lb ai/a per season.
  • carbaryl (Sevin 4F) at 1 lb ai/a. PHI 3 days. REI 12 hr. Retreatment interval 7 days. Limit 6 treatments per year. Do not exceed 6 lb ai/a per season.
  • chlorantraniliprole/lambda-cyhalothrin (Voliam Xpress) at 0.059 to 0.088 lb ai/a. PHI 1 day. REI 24 hr. Retreatment interval 5 days. Do not exceed 0.18 lb ai of lambda-cyhalothrin or 0.2 lb ai of chlorantraniliprole per acre per growing season.
  • cryolite (Kryocide) at 7.7 to 15.4 lb ai/a. PHI 14 days. REI 12 hr. Retreatment interval 7 days. Some formulations are OMRI-listed for organic use.
  • clothianidin (Belay) at 0.05 to 0.067 lb ai/a foliar; 0.15 to 0.2 lb ai/a soil. PHI 7 days foliar, 21 days soil. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.2 lb ai/a per season.
  • cyfluthrin (Tombstone) at 0.038 to 0.044 lb ai/a. PHI 0 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.175 lb ai/a per season.
  • deltamethrin (Delta Gold) at 0.018 to 0.028 lb ai/a. PHI 3 days. REI 12 hr. Retreatment interval 3 days. Do not exceed 0.168 lb ai/a per season.
  • dinotefuran (Scorpion 35SL) at 0.05 to 0.18 lb ai/a foliar or 0.23 to 0.27 lb ai/a for soil. PHI 1 days foliar, or 21 days for soil. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.266 lb ai/a foliar or 0.532 lb ai/a for soil per season.
  • esfenvalerate (Asana XL) at 0.03 to 0.05 lb ai/a. PHI 3 days. REI 12 hr. Do not exceed 0.25 lb ai/a per season.
  • gamma-cyhalothrin (Declare) at 0.01 to 0.015 lb ai/a. PHI 1 day. REI 24 hr. Retreatment interval 5 days. Do not exceed 0.09 lb ai/a per season.
  • GS-omega/kappa-Hxtx-Hv1a (Spear Lep) at 0.8 lb ai/a. PHI 0 days. REI 4 hr. Do not exceed 2 lb ai/a per year.
  • imidacloprid (Admire Pro) at 0.25 to 0.38 lb ai/a. Soil application only. PHI 21 days. REI 12 hr. Do not exceed 0.38 lb ai/a per application.
  • lambda-cyhalothrin (Warrior II) at 0.02 to 0.03 lb ai/a. PHI 1 day. REI 24 hr. Retreatment interval 5 days. Do not exceed 0.18 lb ai/a per year.
  • lambda-cyhalothrin/thiamethoxam (Endigo ZC) at 0.064 to 0.072 lb ai/a. PHI 1 day. REI 24 hr. Retreatment interval 5 days. Do not exceed 0.18 lb ai/a of lambda-cyhalothrin or 0.172 lb ai/a of thiamethoxam per season.
  • malathion (Fyfanon 8) at 1 lb ai/a for pumpkins and winter squash and 1.75 lb ai/a for summer squash. PHI 1 day. REI 12 hr for pumpkins and winter squash; 24 hr for summer squash. Limit 2 treatments pumpkins and 3 treatments squash per year
  • methomyl (Lannate SP) at 0.45 to 0.9 lb ai/a. PHI 1 day at 0.45 lb ai/a and 3 days above 0.45 lb ai/a. REI 48 hr. Do not exceed 5.4 lb ai/a per season. Summer squash only.
  • naled (Dibrom 8E) at 0.94 to 1.9 lb ai/a. PHI 1 day. REI 48 hr. Retreatment interval 7 days. Limit 5 treatments per year. Do not exceed 5.6 lb ai/a per season. Summer squash only.
  • novaluron (Rimon 0.83EC) at 0.058 to 0.078 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 14 days. Do not exceed 0.23 lb ai/a per season.
  • permethrin (Permethrin) at 0.1 to 0.2 lb ai/a. PHI 0 days. REI 12 hr. Retreatment interval 7 days. Do not exceed 1.2 lb ai/a per season.
  • tebuconazole/lambda cyhalothrin (Crossover) at 0.14 to 0. 16 lb ai/a. PHI 7 days. REI 24 hr. Retreatment interval 10 days. Do not exceed 0.48 lb ai/a tebuconazole and 0.18 lb ai/a lambda cyhalothrin.
  • zeta-cypermethrin (Mustang) at 0.035 to 0.05 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.3 lb ai/a per year.

Note: Pesticides may injure cucurbits. The possibility of injury is less when foliage is dry at time of application.