Effect of the nematicide carbofuran on the population development of the citrus parasitic nematodeTylenchulus semipenetrans and predacious soil mites in citrus orchard under organic manure regime of fertilization

Abstract

Effect of the nematicide carbofuran on the population development of the citrus parasitic nematodeTylenchulus semipenetrans and predacious soil mites in citrus orchard under organic manure regime of fertilization. In an Egyptian citrus orchard under farmyard manure regime of fertilization an experiment was conducted for three successive seasons (1993–1995) to investigate the potency of the nematicide carbofuran against the population of the citrus parasitic nematodeTylenchulus semipenetrans Cobb. and any side-effects on predacious soil mites. An initial reduction inT. semipenetrans populations was observed after application, although a remarkable increase in the population occurred afterwards. In contrast, the average number of predators decreased, particularly in 1995. In organic plots without nematicide, predators increased to great numbers andT. semipenetrans caused negligible injury. In the fertilizer-free treatment, theT. semipenetrans population was low although that of predacious mites was high. The study indicated that carbofuran treatments reduced the population of predacious soil mites and in their absence the population of the parasitic nematode,T. semipenetrans was likely to increase.