2007 Season Review: Insects on Fruit

Rick Foster, Department of Entomology, Purdue University

The most important factor affecting insect activity in fruit and insect management decisions in 2007 was the weather. The problem was that it was both hotter than normal and colder than normal in the same year. The early heat and the Easter freeze caused short crops, which had dramatic effects on insect management decisions. The hot weather during most of the season changed the timing of the appearance of a number of insects and prolonged the time when the pests needed to be managed.

For example, potato leafhoppers, which migrate from the South each year, showed up at least 2 weeks earlier than usual. This meant that many crops did not have as much leaf area at the time of their arrival, and the possibility for damage was increased. Japanese beetles usually emerge in the Lafayette area around June 20. In 2007, the first beetles were observed on June 3, and fully 2 weeks earlier than normal. It also appeared that Japanese beetle populations dwindled earlier than normal.

Codling moth usually has two generations in most of the state in most years, with at least a partial 3rd generation in the southern part of the state or in warmer than normal years. In 2007, I think it is fair to say that we had a 3rd generation throughout the state. At Lafayette, it appears that the 3rd generation peaked around September 10. That allowed plenty of opportunity for damage in varieties that matured after that date.

Given the hot weather, I expected that we would have a lot of problems with mites. However, not too many growers reported problems. I attribute this to two factors: the good mite management chemicals that we have available today, and good mite management skills exhibited by our growers.