VIEW ARTICLE

Disease Control and Pest Management

Mobility and Persistence of Carbendazim and Thiabendazole Applied to Soil via Drip Irrigation. Z. Solel, Division of Plant Pathology, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel; Dorit Sandler(2), and A. Dinoor(3). (2)(3)Department of Plant Pathology and Microbiology, Faculty of Agriculture, the Hebrew University of Jerusalem, Rehovot, Israel. Phytopathology 69:1273-1277. Accepted for publication 5 June 1979. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-1273.

The initial distribution, and subsequent mobility, and persistence of benzimidazole fungicides applied via a drip irrigation system to soil in a lemon grove were studied. Carbendazim applied either in solution or suspension was restricted to the 0- to 10-cm layer around the dripper. Sixty to 80% of the fungicide in soil was degraded within 4 wk. Initially, thiabendazole (TBZ) was more uniformly distributed in the soil and subsequently was moved more by leaching than was carbendazim. The TBZ persisted in soil for 22 wk, carbendazim for 10 wk. The uptake of either fungicide by lemon trees under field conditions was minute and did not affect the severity of mal secco disease. In laboratory tests, the leaching of solutions or suspensions of carbendazim in soil columns was insignificant either in dry or wet soil: 85–95% of the applied dose remained in the 0- to 5-cm layer after leaching with water equivalent to 630 mm of rain. In laboratory degradation tests in two soil types, either autoclaved or not carbendazim lasted 9 mo and had a half-life of 4–6 mo. Water extraction of soil amended with carbendazim yielded approximately 3μg/ml. When applied as a drench to soil in pots, carbendazim was taken up by Rough lemon seedlings and accumulated in leaves in amounts up to 40 μg/g leaf tissue. Degradation of the toxicant in leaves was 10% in 35 days. The leaves were completely protected against Phoma tracheiphila.