Vegetable Crop Insect Scouting

David Owens, Extension Entomologist,

Scout for aphids and for striped cucumber beetles. Striped cucumber beetles have not yet been observed in fields, but they typically appear near Memorial Day in our area. With warm weather forecast towards the middle to end of next week, conditions will be good for cucumber beetle activity. Pay special attention to cantaloupe fields and other muskmelons, as these crops are susceptible to bacterial wilt. Male beetles emit an aggregation pheromone when they begin feeding and defecating on the plant. This pheromone brings more beetles in, leading to a ‘feeding frenzy’. Free moisture on the leaf washes the bacteria responsible for wilt into the plant. Aggregations may be intense enough to defoliate plants. Aggregations also tend to be a little spotty, meaning you need to scout the field in multiple locations so as to not miss them.

Solanaceous Crops
While Colorado potato beetle has been active for some time, field migration has slowed recently due to cool weather. Once temperatures reach into the 80s again, be on the lookout for migrating beetles. Also start scouting potatoes for leafhoppers. Action thresholds are ½ to 1 adult per sweep or 1 nymph per 10 leaves. Flea beetles are also active on transplants. They leave a characteristic small shot hole injury to the leaves.