Volume 5 Part 1 Article 50
Title: Breakdown of Chlorinated Insecticides in Mushroom Compost
Author: J.P. San Antonio
Considerable data exist on the persistence and breakdown of pesticides in soil (1). Recent research (3, 4) provided basic knowledge about the use and effects of insecticides added to compost and soil. Little or no information is available, however, concerning the actual breakdown products of different insecticides in mushroom compost. The unique nature of compost and the light and temperature conditions under which mushrooms are grown suggest that investigating the effect of mushroom compost on chlorinated insecticides would be valuable. This report presents the results of analyses of mushroom compost treated with chlorinated insecticides.
Compost was prepared from fresh horse manure. This compost, pasteurized at 130 F for 8 days, was used to fill 3.5-ft2 wooden trays to a depth of 5 inches. Insecticides were applied to the compost just before spawning. They were applied at this time rather than before pasteurization to preclude the effects of pasteurizing conditions on the breakdown of the insecticides or their residues.
Each insecticide was applied to compost in the following manner. A tray of compost (50 lb wet weight) was spread in a 1-2 inch layer on clean paper. The insecticide dissolved in acetone (A.C.S. grade) was sprayed on the compost, which was thoroughly mixed at least 4 times during the spraying. The quantity of insecticide applied resulted in a concentration of 50 ppm in the compost on a wet-weight basis. The volume of acetone used was 5 ml/kg of compost. Insecticides applied were chemically pure as indicated by paper chromatographic analysis. The check consisted of 50 lb of compost treated in the same manner with acetone alone. After treatment the refilled trays were placed in the growing room. The next day grain spawn of Agaricus bisporus ‘White’ was mixed into the surface 4″ of the compost. Mycelial growth occurred at 75 F. The surface of the compost was covered with an inch of loam 3 weeks later. Subsequent growth of the mushrooms occurred at 56 F.Please login to download the PDF for this proceeding.