Whole - plant gas exchange , not individual - leaf measurements , accurately assesses azalea response to insecticides
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چکیده
A comparison of whole-plant and individual-leaf gas exchange measurements was undertaken among azaleas, Rhododendron spp., treated with insecticides used to control the azalea lace bug, Stephanitis pyrioides (Scott). Azaleas in individual-leaf trials received 3 insecticide treatments during three 21-day trials. The whole-plant study included 2 insecticide treatments and was conducted during a 21-day trial. Individual-leaf studies indicated that insecticidal soap and acephate application at higher than recommended rates caused short-term reductions in gas exchange. However, variability among individual-leaf measurements prevented consistent conclusions. Whole-plant gas exchange measurements provided consistent results and confirmed that insectidical soap caused short-term reductions in Pnet and Rdark • Additionally, whole-plant gas exchange measurements enabled growth analyses and demonstrated a reduction in carbon use efficiency attributed to insecticidal soap treatments. Neither acephate nor horticultural oil significantly affected whole-plant gas exchange. Gas exchange parameters for treatments in all trials were not significantly different from the controls by Day 21. 2000 Elsevier Science Ltd. All rights reserved.
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