HALF-LIFE OF NALED UNDER 3 TEST SCENARIOS

Decline of naled residue on filter paper was studied after exposure to ultra-low volume droplets in a settling chamber. Naled-treated filter papers were stored under 3 treatment scenarios: 1) in a dark environm ental chamber at an average relative humidity (RH) of 46.9% and temper ature of 24 degrees C, 2) in a dark environmental chamber at an averag e RH of 87.7% and temperature of 24 degrees C, and, 3) in direct sunli ght in the field. Decline of naled followed first order kinetics in al l cases; consequently, half-life of naled under each treatment was det ermined from the slope of each line. Half-life (+/-1 SD) of naled was 8.17 +/- 1.24, 4.81 +/- 1.18, and 1.37 +/- 0.24 h, for treatment scena rios 1, 2, and 3, respectively. In each test, a significant (P < 0.05) decline in naled residue occurred between initial assessment and 4 h postapplication. The half-life of each treatment scenario was signific antly (P < 0.05) different from that of the other 2 scenarios, indicat ing that both humidity and sunlight affect naled degradation rates.