Author
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CHU, CHANG CHI |
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HENNEBERRY, THOMAS |
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Submitted to: Southwest Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/1/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Chemical application is the only measure that has been effectively to control silverleaf whiteflies since its epidemic in 1991. To achieve the best control of the pest with the least amount of chemicals applied on cotton, we verified, in 1995 and 1996, the action threshold 4 adults per leaf-turn we established earlier from a study in 1993 and 1994 in Imperial Valley, California. For comparison, 15 adults per leaf-turn and an untreated control were used. Economic returns showed that the 4 adults per leaf-turn were the highest. However, cotton lint stickiness was in the moderate range that might reduce the growers' profit. Technical Abstract: Studies were conducted in 1995 and 1996 in the Imperial Valley, California, to determine the effect of Bemisia argentifolii Bellows and Perring on upland cotton yields and honeydew lint contamination. Insecticide applications were initiated on upland cotton for B. argentifolii control at four and 15 adults per leaf-turn. Results showed that initiating chemical control at four adults per leaf-turn produced higher lint yields and less lint stickiness compared to initiating chemical control at 15 adults per leaf-turn. Higher yields and lower lint stickiness occurred at both treatment levels compared to untreated cotton. Initiating treatments at 15 adults per leaf-turn required two and three applications and initiating control at four adults per leaf-turn required five and six applications during 1995 and 1996, respectively. Economic returns based on insecticide costs and lint yield were highest when plots were treated at four adults per leaf-turn. Cotton lint stickiness was not considered in the analyses and discounts for sticky cotton could significantly reduce net monetary returns. |
