Population abundance and spatial distribution of Aphis gossypii Glover (Homoptera: Aphididae) and coccinellids on chilli (Capsicum annuum L.)

M.R. Touhidur, A.B. Idris and M.N. Mohamad Roff

Abstract

The population abundance and spatial distribution of the aphids, Aphis gossypii Glover (Homoptera: Aphididae) and its predator coccinellids (adult) on chilli var. MC 11 (Capsicum annuum L.) were studied at MARDI Station Jalan Kebun, Klang, Selangor from February to July 2003. The mean number of aphids and adult coccinellids per plant at each sampling date were significantly different between the plant strata (lower, middle and upper) and sampling dates (p <0.0001). The number of aphids per stratum was significantly (p <0.05) higher in the lower stratum than in the middle and upper strata. However, the number of adult coccinellids was significantly higher (p <0.05) in the middle and upper strata than in the lower stratum. Populations of aphid and adult coccinellids were highest at 56 DAT, which differed significantly (p < 0.05) from the rest of the sampling dates. The number of aphids per plant at each sampling date was found positive and significant correlation (r = 0.98, p = 0.0001) with the number of adult coccinellids per plant per sampling date. The spatial distribution of aphids was aggregated (ID ranged from 48.57 to 1962.30>1) at all sampling dates throughout the entire cropping period. Similarly, the spatial distribution of adult coccinellids was aggregated (ID ranged from 2.69 to 11.82>1). The possible reasons of the abundance and distribution of aphids and adult coccinellids within chilli plants are discussed.

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