Simulation of Drift Depositional Rate of the Fungicide Fosetyl and Its Effects on Non-vascular Plants: Study Case of the Epiphytic Lichen Pseudevernia furfuracea

Abstract

The epiphytic lichen Pseudevernia furfuracea was exposed to a simulation of drift deposition rate of the fungicide Fosetyl-Al in an indoor controlled environment by testing two exposure factors: pesticide concentrations (based on the application rates of 4kgha-1 and 1.6kgha-1) and drop sizes (anti-drift nozzle: 386-484μm; non-anti-drift nozzle: 159-231μm) for a total of four treatments. Drift for higher application rate was simulated once and that for the lower one twice to reproduce agricultural practices. Following fungicide spraying, we measured the concentration of Fosetyl and phosphonic acid in lichen thalli, and the response of ecophysiological status parameters. No trace of Fosetyl was quantifiable 4days after each treatment, being detected only phosphonic acid whose concentrations stayed substantially unchanged for the whole duration of the experiment (40days) and resulting affected by application rate and not by drop size. Both pesticide concentrations caused a remarkable harmful effect that, however, was statistically significant vs control group only starting from the 20th day of stay in the climatic chamber. The drift associated with the higher rate resulted, on average, to be 83% more effective, with the most affected parameters being membrane integrity, lipid peroxidation and photosynthetic pigments. Because the selected lower rate can be considered a quite low value when compared with the rank of used rates for crop protection, the Fosetyl-Al formulate is classifiable as hazardous for its effect on non-target organisms.