Western spotted cucumber beetle (Diabrotica undecimpunctata)
Western striped cucumber beetle (Acalymma trivittatum)
Pest description, crop damage and life history
Pest monitoring Beet seedlings may be susceptible to beetle damage at emergence. Specific treatment thresholds have not been established for beetle foliage feeding on beet tops in Oregon. In Virginia, to prevent cucumber beetle damage to seedlings, the recommendation is to treat when one beetle per 10 row ft is found.
Be aware of surrounding fields. As grass fields dry down prior to harvest, and when harvested vegetable crops are disked into the soil, sudden surges in beetle pressure occur as beetles migrate in from other areas.
In most years, low ebbs occur in the aboveground adult beetle populations after egg laying and before the summer generation emerges. Sometimes, a crop planting can be delayed until after beetles have dispersed and deposited most of their eggs. Trap-and-spray crops sometimes can be used to draw beetles away from the main crop or intercept incoming beetles at the edge of the field. Trap-cropping is an unproven control method in Oregon.
Management-chemical control: HOME USE
- azadirachtin (neem oil)-Some formulations are OMRI-listed for organic use.
- Beauvaria bassiana-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.
- pyrethins (may be combined with other ingredients)-Some formulations are OMRI-listed for organic use.
Management-chemical control: COMMERCIAL USE
- alpha-cypermethrin (Fastac EC) at 0.012 to 0.025 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 4 days. Do not exceed 0.075 lb ai/a per season. Leaves cannot be used for food or feed.
- Beauveria bassiana (Mycotrol O) at 0.25 to 1 quart/a. PHI 0 days. REI 4 hr. Some formulations are OMRI-listed for organic use.
- bifenthrin + zeta-cypermethrin (Hero) at 0.04 to 0.1 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 7 days. Do not exceed 0.45 lb/a per season. Leaves cannot be used for food or feed.
- carbaryl (Sevin 4F) at 1 to 1.5 lb ai/a. PHI 7 days. REI 12 hr. Toxic in aquatic habitats. Latex-based formulations, such as Sevin XLR Plus, are less hazardous to bees. Do not exceed 6 lb ai/a per season.
- GS-omega/kappa (Spear Biological Insecticide) at 0.2 to 0.8 lb ai/a. PHI 0 days. REI 4 hr. Do not exceed 2 lb ai/a per year.
- methomyl (Lannate SP) at 0.45 lb ai/a. PHI 0 days for roots and 10 days for tops. REI 48 hr. Do not exceed eight applications or 3.6 lb ai/a per year.
- zeta cypermethrin (Mustang) at 0.022 to 0.05 lb ai/a. PHI 1 day. REI 12 hr. Retreatment interval 4 days. Do not exceed 0.3 lb ai/a per season. Tops and roots cannot be used for food or feed.