|Chu, Chang Chi|
|Natwick, Eric - UC COOP EXT, HOLTVILLE CA|
|Boykin, Marcus - PREVIOUS EMP. WCRL, AZ|
Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 1, 1998
Publication Date: N/A
Interpretive Summary: We field-tested 17 short staple cotton cultivars for susceptibility to whitefly infestations in the Imperial Valley, CA. All cottons were susceptible and without insecticide protection, lint yield was 1 bale or less per acre. With insecticide protection lint yield was increased 0.35 to eight times. Overall, Deltapine varieties required fewer insecticide applications compared to Louisiana 877 or Stoneville 474 to produce comparable lint yields. In a greenhouse test, we found that when whiteflies had no-choice of cultivars, there were not significant difference in whitefly infestations among nine cotton cultivars tested.
Technical Abstract: Seventeen upland cotton, Gossypium hirsutum L., cultivars were evaluated in the field for susceptibility to Bemisia argentifolii Bellows and Perring in Imperial Valley, CA from 1992 to 1996. All cultivars were susceptible. Sticky cotton occurred and lint yields were low. In 1995 and 1996, nine untreated and insecticide-treated cultivars were compared using 4.1 adults per leaf turn as an insecticide-treatment action threshold. Lint yields o the insecticide-treated plots increased from 1.2 to 7.9 x in 1995 and from 0.35 to 4.0 x in 1996 compared to untreated cultivars. Deltapine (DPL) 5409 and 5415 on average required 5.5 insecticide applications, DPL 50, 5461, and 5517 required six applications, and DPL 5432 and 5690 required 6.5 applications. Louisiana (LA) 887 required seven applications and Stoneville (ST) 474 required 7.5 applications. In a no-choice greenhouse trial in 1997, the nine cultivars studied were equally colonized with B. argentifolii eggs and nymphs in small leaf cages and adult emergence was not significantly different among cultivars. Results suggest the potential to reduce insecticide applications by selecting appropriate cultivars currently available. Identification of resistance mechanisms and development of breeding programs to incorporate resistance into acceptable upland cultivars appears to be a promising approach for whitefly control.