http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Response of cotton (Gossypium hirsutum L.) leaves to profenofos/adjuvant treatment
Insecticides may cause phytotoxic effects on crops. Addition of adjuvants may alleviate or aggravate such effects. Investigating the differences in plant responses to insecticide/adjuvant treatments may help in selecting a proper adjuvant to reduce insecticide phytotoxicity. This study examined the responses of cotton (Gossypium hirsutum L.) leaves to profenofos[O-(4-bromo-2chlorophenyl)-O-ethyl S- phosphorothioatel/adjuvant treatments. The specific objectives were performed in four sets of experiments. The objective of the first set of experiments was to determine the effects of adjuvants on profenofos-induced visual injury of cotton plants. Profenofos/adjuvant treatments caused negligible injury, while combinations of profenofos with other insecticides in a tank mix solution caused significantly more injury. Addition of petroleum oil (PO) to the mix caused the greatest injury , while addition of Silwet or Plex caused the least injury. Uptake rates of pesticides are often associated with the observed visual injury. The objective of the second set of experiments was to determine the effects of the adjuvants on the uptake rates of profenofos. Uptake rates were determined at 0, 3, 6, and 9 hours after treatment (HAT). Uptake rates were significantly highest for profenofos+PO at 3 and 6 HAT as compared to profenofos alone or with cotton seed oil (CSO). Uptake rates of profenofos with Silwet or Plex, determined in another experiment, were smaller than uptake rates of profenofos with PO or CSO. Uptake rates of profenofos with adjuvants were related to the observed visual injury in the field. Increases in ethylene production are often indicative of phytotoxic effects on the plants. The objective of the third set of experiments was to determine the effects of profenofos/adjuvant treatment on ethylene production of cotton leaves. Profenofos and profenofos with PO or CSO caused a numerical increase in ethylene production; however, the data were inconclusive due to the variability between replicates. Changes in the ethylene production are often preceded by changes in I-aminocyclopropane-l-carboxylic acid (ACC). The objective of the fourth set of experiments was to determine the effect of profenofos/adjuvant treatment on the rate of ACC production. Profenofos and profenofos with PO or CSO failed to induce changes in the ACC pool.