Bean Aphids
    
    Bean aphids are showing up in the Suction traps in Burley, and Aberdeen. We suspect that many of these aphids are flying in search of winter hosts (snowball and syringa bushes) rather than more beets. In general, insecticide treatment for bean aphids in sugar beets is not recommended unless more than 5 % of the plants have large colonies. Homeowners with snowball bushes might want to treat them with dormant oil this winter to prevent damage next spring.

Russian Wheat Aphids

    According to the Suction Traps, there are still too many aphids too plant safely at Soda Springs, but it is probably to dry to plant in most areas anyway. We expect these numbers will decrease soon.

Fall Aphid Flights

    Aphids are usually quite specific with respect to winter plants. For example, the green peach aphid, which colonizes many types of plants in the growing season, overwinters only on peach and apricot. In the fall, many species have a sexual cycle triggered by cooler temperatures and shorter days. As days become shorter, winged females are produced on summer host plants. Unlike the winged forms which occur in summer, these fall forms do not reproduce on summer hosts, but fly in search of woody winter hosts. Once there they produce wingless, egg laying females. At the same time, winged males are produced on summer plants. These also migrate to winter hosts, where they mate with the egg laying females to produce overwintering eggs.  Some aphids with this type of life cycle and their alternate hosts are:

    Other aphids have sexual cycles, but remain on the same hosts all year. Examples include the English grain aphid, greenbug, pea aphid, and spotted alfalfa aphid. These overwinter as live bearing summer females.

Funded by the University of Idaho Agricultural Experiment Stations and the Wheat & Barley Commissions.

Samples collected August 24 & 31, 2001 

 *Trap motor out