S. Sambath , K. C. Joshi , R. Krishnamurthy

Abstract

Temperature and humidity are the two main factors that influence the rate of survival, oviposition, growth and development and the fecundity of an insect. Experiments were carried out during 1996-97 to determine the effect of temperature and relative humidity on the egg, larval, pre-pupal and pupal period of Albizia foliage feeder, Spirama retorta Cram. (Lepidoptera:Noctuidae), a devastating pest of forest nurseries and young plantations in Central India. The recorded field temperature during study/survey period was 5 to 45°C and relative humidity 20 to 80% in Central India covering the state of Madhya Pradesh, Maharashtra and Orissa. Study of the effect of temperature and humidity revealed that the best suited optimum temperature and relative humidity was between 30-35°C and 60-80% which enhanced the viability of eggs and shortened the egg, larval, pre-pupal and pupal duration. Low temperature (5 - 25°C) and humidity (20 - 60%) lessened the viability of eggs and increased the mortality and the duration of various life stages. The maximum mean viability of eggs (99.00 ± 1.00) was recorded at 30°C and 80% where as the shortest egg period was 3- 4 days observed at 35°C and 40-80% relative humidity. The shortest mean period in days was also observed for larval (11.12 ± 0.3750), prepupal (1.62 ± 0.1250) and pupal (9.67 ± 0.2870) between 30 - 35¤C and 60-80%. These finding were correlated with the field temperature and humidity and found that temperature, humidity and species of food plants (quantitative and qualitative) favored this insect to occur in an epidemic condition, in forest nurseries and young plantations during monsoon season.

Keywords

Spirama retorta, Epidemic, Albizia lebbek, A. Procera

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R. Krishnamurthy , Ramesh Babu. M. Anbazhagan , G. Banerjee , K. A. Bhagwat

Abstract

The leaves of Eucalyptus longifolia and Peltaphorum ferrugrntum. Two very commonly found avenue trees in IPCL (Indian Petro Chemical Ltd.) township and Bauizinia lomentoso, a less distributed species were studied to evaluate the injury done by chronic low levels of pollution. All the three species retained less number of leaves per twig. E. longifolia and P. ferrugineun could maintain photosynthetic leaf area and leaf dry matter accumulated per leaf equal to the control. Under pollution stress leaf starch levels Were low but they maintained high levels of sugars. The more prevalent species E. longifolia and P. ferrugineum incorporated only about 30 per cent more sulphur in their leaf system. Whereas B. tomenlasa had 70 per cent incorroration. The incorporated sulphur probably transferred into other sulpher containing compounds like glulathionc and not in aminoacids. Pollution stress brought about a decrease in leaf protein, DNA. Ascorbic acid levels. Eucalyptus accumulates phenols.

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