SEASONAL ABUNDANCE OF PHYTOPHAGOUS AND PREDATORY MITES ON MANGROVE VEGETATION AND AGRI-HORTICULTURAL CROPS OF SUNDARBAN BIOSPHERE RESERVE

About authors:

Ghoshal S., P.G Department of Zoology, Bangabasi College, Kolkata-09, India
Gupta S.K., Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, India

В. Mukherjee, Department of Pharmaceutical Technology, Jadavpur University, Kolkata-700 032, India

Acknowledgments:

The authors are thankful to the Ministry of Environment and Forests, India, for providing the research grant to carry out the study, to Prof. Amalesh Chaudhury, S.D.M.B.R.I. Secretary, for laboratory facilities and to Mr. Ashis and Nitish Jana of S.D.M.B.R.I., Sagar Island, for their help rendered during recording of field observations.

Annotation:

Seasonal abundance fluctuations of phytopha-gous and predatory mites on two species of man-grove vegetation and agri-horticultural crops in the Sundarban Biosphere Reserve were studied in 2001 and 2002. In Avicennia alba the maximum abun-dance of phytophagous mites was observed in Oc-tober, while that of predatory mites was noted in July. The phytophagous mite abundance values correlated negatively with the temperature, RH, rainfall as well as the predatory mite abundance, whilst the abundance of predatory mites was posi-tively correlated with the temperature, RH, and rainfall. In Rhizophora mucronata, the phytopha-gous mites in general were suppressed during both years and the predatory mites were fairly dominant throughout the year. The peak abundance of pred-atory mites was observed in October. The correla-tion coefficient of phytophagous mites with the temperature, RH, rainfall and the predatory mite abundance was negative and those of predators were positive with temperature, RH, rainfall. In case of Citrus sp., the phytophagous mite peaks were reported in January whilst the predatory mite abundance was low. The correlation coefficient was negative with the temperature, RH, rainfall for phytophagous mites during both years of study, whilst it was positive with all these factors in case of predatory mites. In Guava both phytophagous and predatory mites were noticed during the entire study period for which observations were made. The peak abundances of phytophagous and preda-tory mite were recorded in February and August.

It was found that Amblyseius largoensis pre-dominated on four host plants, whereas Tetranychus urticae was found to be the most dominant phytophagous mite species on Avicennia alba and Rhizophora mucronata. Schizotetranychus hindus-tanicus had the highest abundance on Citrus sp. and Eotetranychus hicoriae on guava.

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