Journal of Environment and Sociobiology

D. Suresh Chand ¹, M. C. Muralirangan ²

Affiliations
1 Arunachal Pradesh Research Centre, Zoological Survey of India, Itanagar-791113, IN
2 G.S. Gill Research Institute, Guru Nanak College, Chennai–600 042, IN

Abstract

Present investigation aimed at evaluating the yield loss of two rice cultivars CO43 and CO45 by the small rice grasshopper Oxya nitidula (Walker). Three different growth stages of the cultivars were selected 31 days after sowing (DAS), 46 DAS, and 61 DAS for evaluating the damage potential by the small rice grasshopper. Infestation was carried out at different population level, 2 insects/cage, 4 insects/cage, 6 insects/ cage and 8 insects/cage. Damage caused by the insects was directly related to the grains harvested on the two rice cultivars. The result suggests that grain loss increased with increasing number of insects infesting the plant. At 31 DAS treatment damage was more, compared to other DAS treatments.

Keywords

Oryza sativa, Oxya nitidula, Yield Loss.

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D. Suresh Chand ¹, S. Albert ², K. P. Sanjayan ²

Affiliations
1 Zoological Survey of India, M-Block, New Alipore, Kolkata-700 053, IN
2 G.S. Gill Research Institute, Guru Nanak College, Velachery, Chennai 600 042, IN

Abstract

The plant community structure of the Vandalore Reserve Forest (Tamil Nadu) which represents a natural scrub-jungle ecosystem, is described in terms of the dispersal and distribution patterns of some of the plant species that are relatively common in the habitat. The generalization that the tropical species are relatively uniformly dispersed did not hold. The six plant species that were selected either randomly distributed or clumped in dispersion. Atalantia tnonophylla which was clumped in dispersion had more abundance value, importance index, and density in the forest, when compared to the other five plant species. The food preference of Diabotocaiantops pingiiis (Walker) to the selected six plant species through a 'no-choice' experiment showed that it rejected Pavetta indica and Flacoiirtia indica. The population analysis of D. pinguis by selecting 25 quadrats, suggested that the insect was found to be present in 21 quadrats.

Keywords

Plant Community Structure, Dispersion, Importance Value, Diabolocatantops Pinguis, Food Preference.

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