Biological control of cotton aphids using beneficial fungus

There has been a significant shift in cotton pest guild in Alabama during the last two decades. Aphids are now one of several insects that occur annually on most cotton fields statewide. Economic losses vary with available moisture but excessive stress to the fruiting plants is highly visible. Aphids have a high reproductive potential and a short life cycle, which offers tremendous potential for resistance to insecticide controls. Most insecticides only maintain their effectiveness against aphids for a few seasons. Cotton growers in Alabama are utilizing a naturally occurring fungus to suppress aphid populations. The fungus usually occurs about 10-15 days after aphids reach economic levels. The Alabama Cotton IPM program, in cooperation with Cotton Incorporated and the University of Arkansas, participates in an Aphid Fungus Sampling Service which can predict natural aphid declines before it is visible to the naked eye in the field. The program works like this—fields are scouted by agents, consultants or extension entomologists for aphid buildups. Samples are collected from problem fields and sent by express mail to the diagnostic laboratory at the University of Arkansas. Aphids are examined in the laboratory for presence of the beneficial fungus and the percentage of infected aphids is communicated back to the sender within 24 hours. If the infection level is above 15%, a natural aphid decline is predicted. Information from all samples analyzed within a multistate area is posted on a website so that the overall picture is also available to cooperators. For more information please contact: Dr. Barry Freeman, Department of Entomology & Plant Pathology, Auburn University, AL 36849. E-mail: bfreeman@acesag.auburn.edu