Vegetable Crop Insects – April 29, 2011

With the warm temperatures this past week, we have seen a significant increase in asparagus beetle populations in fields throughout the state. As indicated last week, it is important to check for eggs as well as adult beetles feeding on spears. As a general guideline, a treatment is recommended if 2% of the spears are infested with eggs. Since adults will also feed on the spears, a treatment is recommended if 5% of the plants are infested with adults. For a picture of asparagus beetle eggs, adults and larvae please refer to the following link:

As soon as plants are set in the field begin scouting for aphids, cucumber beetles and spider mites. When sampling for aphids, be sure to watch for beneficial insects as well, since they can help to crash aphid populations. As a general guideline, a treatment should be applied for aphids when 20% of the plants are infested, with at least 5 aphids per leaf but before populations explode.

As soon as plants emerge be sure to sample fields for Colorado potato beetle adults, especially if an at-planting material was not used. A treatment should not be needed for adults until you find 25 beetles per 50 plants and defoliation has reached the 10% level.


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