Studies on the Systemic Uptake of Toxic Phosphorus Esters by Plants: Morphological Effects of Foliar Applications of the Organophosphate Insecticides Mevinphos and Methyl Demeton on Selected Plant Species

摘要

Data relating the tolerance of economically-important plants to repetitive aerial applications of organophosphorus insecticides is of interest to military pest control programs. The organophosphorus insecticides 2-carbomethoxy-1-methylvinyl dimethyl phosphate (mevinphos) and a mixture of the two isomers O, O-dimethyl S-(2-(ethylthio)ethyl) phosphorothioate and O,O-dimethyl O-(2-(ethylthio)ethyl) phosphorothioate (Methyl Demeton) were applied to the foliage of fifteen economically important plants at the rate of 5, 10, 20, and 40 pounds active ingredient per acre. Data on morphological effects were taken 1, 3, 7, and 10 days after treatment. Statistically significant differences were observed when plant species, insecticides, and concentration parameters were evaluated. In general, broadleaf plants were more susceptible to the insecticides than were grasses. Severe morphological injuries (e.g., leaf necrosis) were observed on soybeans, cotton, and tomato plants one day after foliar treatment, while seven days were required before comparable injuries were noted on corn and sorghum. While Methyl Demeton (Meta-Systox) produced significantly more damage to the plants than did Mevinphos (Phosdrin) at each level of concentration, the rate of increase was similar. Despite severity of initial damage, all plants recovered within 30 days of treatment except soybeans. (Author)