Insects pests and their arthopod natural enemies in a paddy field ecosystem
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Date
1997-11-22
Authors
Bambaradeniya, C. N. B.
Edirisinghe, Jayanthi P.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya
Abstract
A research project is currently in progress at Bathalagoda to assess the biological diversity in a paddy field ecosystem. This paper reports the insect pests of paddy and their arthropod predators and parasitoids present during the different phases of the paddy field and growth stages of the paddy plant and in relation to the use of biocides. Insects on vegetation were sampled using a sweep net, a quadrate, a Blower vac suction device and a light trap, while aquatic insects were sampled using a dipper.
A total of 43 species of pest insects belonging to 20 families and 7 orders, 94 species of arthropod predators belonging to 34 families and 8 orders together with 27 species of insect parasitoids in 12 families and 2 orders were recorded during four consecutive paddy cultivation cycles. The pest insects were dominated by Hemipteran bugs (18 species in 6 families) followed by Lepidopterans (7 species in 4 families), Orthopterans (6 species in 2 families), Co!eopterans (6 species, 2 families), Dipterans (4 species, 4 families), Thysanopterans (1 species in 1 families) and Hymenopterans (1 species in 1 families). The predatory arthropods were dominated by 48 species of spiders in 11 families followed by Coleopterans (14 species in 6 families), Hemipterans (11 species in 8 families), Odonates (11 species in 3 families). Hymenopterans (5 species in 1 families). Orthopterans (3 species in 2 families). Dermapterans (l species in 1 family) and Phasmids (l species). The insect parasitoids collected consisted of Hymenopterans (25 species, 10 families) and Dipterans (2 species in 1 family). Sampling at 2 week intervals during a paddy cycle indicated that the vegetative stage of the plant harboured the most number of pests, while the grain ripening stage harboured more predators. Application ofbiocides affected both pests and predators and the latter more drastically.
Description
Keywords
Zoology , Insects , Pests , Paddy cultivation
Citation
Proceedings and Abstract of the Annual Research Sessions, November 22, 1997, University of Peradeniya, Sri Lanka pp 111-120