ABSTRACT
Four cotton fields were monitored over the 1992 growing season for cotton aphids and for the aphid pathogen Neozygites fresenii. In each field, aphids began to build their numbers in early or mid-July. H. fresenii also appeared in alatae in early or mid-July. N. fresenii epizootics brought down the cotton aphid population in each field by late July or early August. Epizootics lasted about 1 week during which aphids declined to very low numbers. A survey of cotton fields throughout the north Mississippi delta on July 23 and 28 showed N. fresenii to be widespread with some fields showing signs of aphid population crashes.
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