Sampling Sweetpotato Whiteflies in
Cotton
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Ellsworth,
P.C., J.W. Diehl, T.J.
Dennehy, and S.E.
Naranjo. 1995 (Rev. 11/2000). Sampling Sweetpotato Whiteflies
in Cotton . IPM Series No. 2. Publ. No. 194023. University of Arizona,
College of Agriculture and Life Sciences, Cooperative Extension, Tucson,
Arizona. URL: http://cals.arizona.edu/crops/cotton/insects/wf/wfsampl.html
Whitefly Management Starts With SamplingBecause whitefly numbers in cotton can vary from year to year, sampling helps you avoid costly errors associated with whitefly control:
Action Thresholds & Percent Infested LeavesResearch shows that insecticides should be applied when a threshold density of 5 whitefly adults per leaf is present. However, counting exact numbers of adult whitefly on every leaf is time-consuming and unneccessary. Because a predictable relationship exists between numbers of adult whiteflies per leaf and the percentage of leaves infested with just three or more whitefly adults, no more than three whiteflies need to be counted on a given leaf. This method increases sampling efficiency and has been confirmed on over 8000 acres of commercial cotton under a wide variety of field conditions.
HOW TO SAMPLE
Count Sweetpotato Whiteflies Only !Do not include bandedwinged whiteflies in your whitefly counts because they rarely warrant pesticide treatment. The bandedwinged whitefly is often found in cotton, wild sunflower, weeds, or melons in the early spring and summer. It has gray-colored bands on the wings, while the sweetpotato whitefly has no bands. The body of the adult bandedwinged whitefly is ashen-gray in color while the sweetpotato whitefly is a creamy-yellow color.
Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, James A. Christenson, Director Cooperative Extension, College of Agriculture and Life Sciences, The University of Arizona. The University of Arizona is an equal opportunity, affirmative action institution. The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities. Any products, services, or organizations that are
mentioned, shown, or indirectly implied in this web document do not imply
endorsement by The University of Arizona. Questions concerning this publication can be addressed to: peterell@ag.arizona.edu |
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