As you create your pest management programs for the rest of the season, make sure you keep pollinators and natural enemies in mind. Most cucurbits are obligately reliant on pollinators to set fruit and secure high yields. Further, many common cucurbit pests are controlled by natural enemies. For example, aphid infestations are often curbed by parasitoid wasps (pictured below). Ideally, non-chemical options should be prioritized (e.g., exclusion netting, trap cropping) but we don’t always live an ideal world. If you need to make an insecticide application, choose compounds with reduced toxicity to beneficial insects (options are shown below in Table 1).
- Scout your field. Try to only spray when you need to spray. Use thresholds (described below in Table 1) to determine when an insecticide application is necessary. It’s possible that your preventative pyrethroid application is doing more harm than good. Pyrethroids in particular have a high “flaring potential” since they can disrupt natural enemies that provide FREE pest control.
- Rotate chemistries. Take the IRAC code into consideration before you make an insecticide application and limit the number of sprays with the same insecticide class. This will prolong the efficacy of insecticide materials for the future.
- Pollinator protection. While many insecticide products are safe to apply during the bloom period (although you still can’t apply during pollinator foraging), there are a fair number of neonicotinoids and pyrethroids that are not safe to apply during the bloom period at all (listed in Table 1 as ‘Highly toxic’). If you plan to use these products, make sure you position them well before or after bloom to limit negative effects on pollinators.
– Ashley Leach (OSU Entomology) and Jim Jasinski (OSU Extension)