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Cotton Aphid Management - Status and Needs

L. D. Godfrey and J. F. Leser


 
ABSTRACT

During the late 1980's and the 1990's, the cotton aphid became an important pest of cotton across the Belt and warrants annual consideration in cotton IPM programs. Numerous changes in insecticide use patterns, cotton varieties, crop mosaics, and other factors, including possible biotic changes in the aphid and/or natural enemies, account for the emergence of cotton aphid as a significant pest. In the more arid areas of Texas (High and Rolling Plains) and California, the cotton aphid continues to be a key pest. The lack of natural aphid control from Neozygites fresenii and the scarcity of rainfall in the late summer to remove any honeydew on lint have added to the pest potential of cotton aphid in these areas. Much research has been focused on cotton aphid biology and management in West Texas and California during the last 10 years. Following the major outbreak of cotton aphids in West Texas in 1991, a task force was formed to prepare a list of management suggestions based on what was already known and information gained through experiences managing the 1991 aphid outbreak. In California, early- and late-season aphid outbreaks occurred from 1991-93; thresholds and management options were of utmost, immediate importance. It was clear from the onset that considerable knowledge gaps existed in our knowledge of aphid ecology as it related to developing sound IPM strategies for this pest. The ensuing years of research provided a wealth of information that was subsequently incorporated into management guidelines in California and Texas. Research objectives included non-chemical (biological, cultural, and host plant resistance) means of management, chemical efficacy, insecticide resistance monitoring, treatment thresholds, sampling protocols, and indirect effects on cotton aphids of management actions against other insect pests. Current Texas studies are addressing issues such as factors responsible for late aphid outbreaks; the use of sprinkler irrigation to cleanse contaminated lint in the field; establishing the quantitative relationship between aphid numbers, insect sugars deposited and level of processing problems; elimination of plant sugar problems through harvest management or variety selection; and the determination of gene(s) responsible for sugar concentration which is optimal for aphid development with the goal of modifying this through plant breeding. In California, ongoing studies on cotton aphids include research on insecticide resistance status and factors influencing the magnitude of resistance in cotton aphids, cultural controls, expansion of the natural enemy complex, aphid overwintering strategies and seasonal life history, and the influence of lygus bug management approaches on the abundance of cotton aphids. FQPA has added an extra incentive to find non-chemical means of managing the aphid problem. New effective aphicides still need to be developed to be available for remedial control and to replace insecticides which may be lost to the FQPA or resistance.



Reprinted from Proceedings of the 1999 Beltwide Cotton Conferences pp. 37 - 40
©National Cotton Council, Memphis TN

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Document last modified Monday, Jun 21 1999