ABSTRACT
Cauliflower crops were grown in several regions and seasons (spring and summer). Five days after planting, the plants were treated against the root fly by pouring onto soil around the plant stem an emulsion of chlorfenvinphos [2-chloro-1-(2,4-dichlorophenyl) ethenyl diethyl phosphate] in water. The fields were divided into plots. Onto each plot, one of the organic fertilizers, city refuse compost, mushroom cultivation compost, or cow manure was applied at the rate of 100 tons/ha, 1 or 3.5 months before the insecticide treatment. There were also control plots which were not treated with any of the organic fertilizers. During the first 50 days crop period which followed the insecticide treatment, the chlorfenvinphos soil concentrations were always greater in the organic fertilizer-treated plots, than in the untreated ones (controls). The intensity of the organic fertilizers effect as to the increase of chlorfenvinphos soil persistence was in the following increasing order: city refuse compost less than cow manure less than mushroom cultivation compost. The organic fertilizer effects were greater when they had been soil-incorporated 3.5 months--instead of 1 month--before the chlorfenvinphos soil treatment. The increase of the insecticide soil concentrations--due to the organic fertilizers treatments--should increase the plant protection efficiency during the period of the first 50 days, during which time the young plants are the most sensitive to insects.(ABSTRACT TRUNCATED AT 250 WORDS)
