MSc

Mites constitute the most important group of non-insect pests in agriculture. Vegetable crops in particular, are subjected to infestation by a number of mite species, leading to heavy economic loss. The average yield loss in vegetable crops due to mite pests in India has been estimated to be around 25 per cent (Gupta, 1991). Predatory mites play a major role in reducing the populations of phytophagous mites and are able to feed on alternate sources of food and can survive in the absence of prey mites.
The present study was undertaken at the Acarology Laboratory, Department of Agricultural Entomology, College of Horiculture, Vellanikkara during 2014 – 2015 to explore the diversity of predatory mite fauna in the vegetable ecosystems of Thrissur district, Kerala. The objectives of the study were to document the species diversity of predatory mites associated with phytophagous mites in vegetable ecosystems in Thrissur and also to develop a taxonomic key for the identification of predatory mite fauna in vegetable ecosystems.
A purposive survey was undertaken to explore the mite fauna associated with the vegetable crops viz. amaranthus, brinjal, bhindi, bittergourd, chilli, cowpea, coccinia, cucumber, snakegourd and snap melon in major vegetable growing tracts of Thrissur district, Kerala. The taxonomic characters of the collected mite specimens were studied and were classified upto species level. Based on the characters studied and the species identity established, a detailed dichotomous key to the identification of the predatory mites studied was prepared.
A total of 18 species of predatory mites belonging to six families were encountered in the study. The predatory mite families included Phytoseiidae, Stigmaeidae, Cunaxidae, Bdellidae, Tydeidae, and Acaridae represented by the
genera Neoseiulus, Amblyseius, Typhlodromips, Euseius, Paraphytoseius, Phytoseius, Scapulaseius, Agistemus, Cunaxa, Bdella, Tydeus and Pronematus. The associated phytophagous prey mite families recorded were Tetranychidae, Tenuipalpidae and Tarsonemidae represented by the genera Tetranychus, Eutetranychus, Brevipalpus and Polyphagotarsonemus.
Faunal studies in ten vegetable crops revealed highest species richness of predatory mites in brinjal, with a total of 18 species belonging to five different families. Mites in the family Phytoseiidae were found to be the most common predators in the vegetable fields of Thrissur district. Among the phytoseiid mites, Neoseiulus longispinosus was identified as the major species, associated with phytophagous mites in all the vegetable fields surveyed. Other species were Amblyseius paraaerialis, Amblyseius largoensis, Euseius macrospatulatus, Euseius sp. nr. prasadi, Typhlodromips syzygii, Paraphytoseius orientalis, Phytoseius intermedius and Scapulaseius sp. Occurence of Euseius sp. nr. prasadi and Phytoseius intermedius are new reports for Kerala.
Predatory mites, Cunaxa sp. of the family Cunaxidae and Bdella khasyana of the family Bdellidae were recorded in chilli, cowpea and snap melon. Bdella khasyana is a new report for Kerala. Four species of mites belonging to the family Stigmaeidae viz., Agistemus gamblei, A. fleschneri, A. garrulus and A. macrommatus were recorded on bhindi, bitter gourd, brinjal, chilli and snake gourd. Occurence of A. fleschneri, A. garrulus and A. macrommatus are new reports for Kerala.
The predatory mites Tydeus gossabaensis and Pronematus anconai of the family Tydeidae recorded in amaranthus, bhindi, brinjal, chilli, cowpea and snake gourd are new reports from Kerala. One species of astigmatid mite in the family Acaridae was also collected from brinjal and cowpea during the study.