caa a22 4500 397570651 CHVBK 20180308164840.0 cr unu---uuuuu 161202e19961201xx s 000 0 eng 10.1093/ee/25.6.1267 doi (NATIONALLICENCE)oxford-10.1093/ee/25.6.1267 Bemisia argentifolii (Homoptera:Aleyrodidae) Action Thresholds and Cotton Photosynthesis [Elektronische Daten] [Wee L. Yee, Nick C. Toscano, Chang-Chi Chu, Thomas J. Henneberry, Robert L. Nichols] Action thresholds for whiteflies, Bemisia argentifolii Bellows & Perring on cotton, Gossypium hirsutum L., are being developed to determine the whitefly densities at which cotton should be treated with insecticides to prevent lint yield losses. However, the effects action threshold treatments have on cotton photosynthesis have not been determined. Changes in the photosynthetic rate of cotton can be used to assess damage to cotton early in the season before lint is harvested. In this study photosynthetic rates and stomatal conductance of cotton treated at 4 different action thresholds for whiteflies were measured 12 times during July and August 1995 in the Imperial Valley of California using a portable photosynthesis system. Action thresholds were 2.5, 5, 10, and 20 adults per leaf. Untreated control plots were also used for comparison in a 5 × 5 Latin square design. Adult, egg, and nymphal whitefly densities on untreated cotton were significantly higher than those on all other treatments. In general, no differences in densities of any stage were seen among the 2.5, 5, and 10 treatments. Densities from the 20 treatment were variable. Photosynthetic rates of untreated cotton leaves were usually significantly lower compared with those of 2.5, 5, and 10 treatments. In general, no significant differences in photosynthetic rates were seen among the 2.5, 5, and 10 treatments. Photosynthetic rates of leaves from the 20 treatment were significantly lower and higher than leaves from the other treatments and the untreated control, respectively, on some dates. In general, no significant differences were detected in stomatal conductance among the 2.5, 5, and 10 treatments, and results were similar to those seen with photosynthesis. Based on photosynthetic rates and stomatal conductance, measurable physiological damage to cotton leaves occurs between action thresholds of 10-20 adult whiteflies per leaf. © 1996 Entomological Society of America Pest Management and Sampling nationallicence Bemisia argentifolii nationallicence Gossypium hirsutum nationallicence action thresholds nationallicence whitefly densities nationallicence photosynthetic rate nationallicence stomatal conductance nationallicence Yee Wee L. Department of Entomology, University of California, Riverside, CA 92521 aut Toscano Nick C. Department of Entomology, University of California, Riverside, CA 92521 aut Chu Chang-Chi Western Cotton Research Laboratory, USDA-ARS, 4151 Highway 86, Brawley, CA 92227 aut Henneberry Thomas J. Western Cotton Research Laboratory, USDA-ARS, 4135 East Broadway, Phoenix, AZ 85040 aut Nichols Robert L. Cotton Incorporated, 4505 Creedmoor Road, Raleigh, NC 27612 aut Environmental Entomology Oxford University Press 25/6(1996-12-01), 1267-1273 0046-225X 25:6<1267 1996 25 ee https://doi.org/10.1093/ee/25.6.1267 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/ee/25.6.1267 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yee Wee L. Department of Entomology, University of California, Riverside, CA 92521 aut NATIONALLICENCE 700 1- Toscano Nick C. Department of Entomology, University of California, Riverside, CA 92521 aut NATIONALLICENCE 700 1- Chu Chang-Chi Western Cotton Research Laboratory, USDA-ARS, 4151 Highway 86, Brawley, CA 92227 aut NATIONALLICENCE 700 1- Henneberry Thomas J. Western Cotton Research Laboratory, USDA-ARS, 4135 East Broadway, Phoenix, AZ 85040 aut NATIONALLICENCE 700 1- Nichols Robert L. Cotton Incorporated, 4505 Creedmoor Road, Raleigh, NC 27612 aut NATIONALLICENCE 773 0- Environmental Entomology Oxford University Press 25/6(1996-12-01), 1267-1273 0046-225X 25:6<1267 1996 25 ee Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford