SLOW-RELEASE DELIVERY SYSTEM FOR HERBICIDES IN CONTAINER-GROWN STOCK

Metolachlor, applied to the surface of leaching columns as dicalcium p hosphate tablets, was recovered over a period of 25 d compared with 2 and 3 d for emulsifiable concentrate and granular formulations, respec tively. In similar studies, approximately 27% of napropamide was recov ered from tablets during the same period. Adding an adjuvant to the na propamide tablet mixture increased the recovery rate to 55%. Tablet ha rdness and size had little effect on the release rate of napropamide. Tablets containing 4% al napropamide released greater amounts of herbi cide at a single collection period than did tablets containing 1% ai. Adding an adjuvant to the napropamide tablet mixture significantly imp roved Italian ryegrass control in the area adjacent to herbicide place ment.