Informatics Publishing Limited

Shivesh Kumar , S. K. Sharma , Tarun Kant , C. J. S. K. Emmanuel

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S. T. Ahmed , Shivesh Kumar

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Seasonal variation in the population of stem gall chalcid , E. settitibia was snrveyed and studied in a young stand of P. cineraria in the experimental field during 1998-1999. Census was carried out for five stages i.e. (i) potential eggs , (ii) newly hatched larvae , (iii) larvae in galls , (iv) pupae in galls and (v) emcrging adults. Population density of potential eggs was recorded to he 18659 ± 968 eggs per m³. The population density has been calculated based on the density of 67 females and the mean fecundity per female. The population density of newly hatched larvae was 3621±39 per m³. Out of the density of total eggs deposited , only 61.93% larvae were hatched. The major mortality factor of the newly hatched larvae was observed to be the failure of hatched larvae to penetrate into the cambial layers of the growing shoots. The population density of first instar larvae in galls was 2598±98 individuals per m³. , and about 64% of newly hatched larvae died before the formation of gall. The population density of pupae in galls was 1785 ±360 per m³. , and 31.2% mortality of larvae was observed inside the emerging galls. A group oflarvae live together in a single gall and the number of larvae per gall ranged from 21-268 with a mean of 129.9 larvae per gall. Statistical correlations between egg clusters and total eggs; egg hatched and total eggs laid and larval mortality and total eggs , indicated that these parameters are positively correlated with each other under similar conditions of abiotic factors. The highest population of adults (68.82 adults per gall) was recorded in the second fortnight of August when the optimum ranges of abiotic factors i.e. temperature (23.5 to 34.5°C) and relative humidity (60 to 71 %) were available in the field whereas the minimum number (2.95 adults per gall) was observed in the month of December.

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S. I. Ahmed , K. K. Chaudhuri , Meeta Sharma , Shivesh Kumar

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Insect pests are amongst the most important detrimental factors in the successful establishment and growth of Prosopis cineraria (Linn) (Khejri) and Tecomella undulata (Sm.) Seem (Rohida) in arid and semi arid zone of Rajasthan. P. cineraria, the 'king tree' of Indian arid region, is revered for its range of products and services rendered to desert inhabitants. Khejri has a unique distinction of being referred in a variety of contexts, besides being a tree of socio-economic importance, it bears religious legends. T. undulata (Sm.) Seem, is one of the co-dominating tree species in the desert forests of western Rajasthan and adjoining lands of Haryana and Punjab. Twenty six potential pests on P. cineraria and P. juliflora have been recorded from arid and semi-arid areas. Of them, 18 species have been recorded as new pest records on P. cineraria including four species of long horned beetles viz., Derolus iranensis (=descicollis) Pic, Aeolesthes holosericea Fab, Hypoeschrus indicus Gahan and Acanthophorus serraticornis (Oliver) which have been recorded to exhibit severe damage to Prosopis cineraria in four north western districts of Rajasthan. In all 64 insect species have been recorded on T.undulata in the form of pests. Of them, 24 insect species were observed for the first time to cause mild to severe damage to marwar teak in arid and semi arid areas. Seedlings and young plantations of T. undulata are frequently severely attacked by a serious curculionid pest, Patialus tecomella throughout the tract of its distribution in arid and semi-arid areas. Natural enemy complex recorded on the insect pests of Prosopis cineraria and Tecomella undulata during the course of these investigations play an important role in controlling the outbreaks of insect pests of these economically important tree species in arid and semi-arid regions. Twenty species of parasites, thirteen species of predators and three species of entomopathogens were found associated with the potential insect pests of Khejri and Rohida A potential pupal parasite, Billeae atkinsoni has been recorded to keep the pest populations below the level of economic threshold. Integrated management strategy has been discussed to save the Khejri trees from large scale drying.

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S. I. Ahmed , Shivesh Kumar , Sahadev Chouhan

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S. Murugesan , Ameenullah Khan , Shivesh Kumar , S. Durairaj

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S. I. Ahmed , Shivesh Kumar

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The field population of Taragama siva Lefebvre, a polyphagous forest insect pest, was noticed severely infected with a polyhedrosis virus, at Jodhpur and adjacent localities during AugustSeptember, 1995. In field studies, a high incidence of disease was present in young larval population. Sample oflate instar larvae collected from field showed 96.66 per cent infected material. Although, one species ofa dipterous parasite is known to attack T. siva, but control by this agent, in the present study, appeared negligible. The number of cocoons formed at the end of outbreak was extremely low. There was good evidence to suggest that the virus infection was the main cause in the sudden collapse of pest population.

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S. Murugesan , Shivesh Kumar , R. Sundararaj

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S. Murugesan , Shivesh Kumar

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