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K. R. Sasidharan , R. V. Varma , M. Sivaram

Abstract

Several insect pests are associated with Casuarina equisetifolia L. in India. Among them, the bark eating caterpillar, Indarbela quadrinotata Walker (Metarbelidae: Lepidoptera) has attained serious pest proportions in Tamil Nadu State, which is located in the southern part of the country. The impact of I. quadrinotata on the growth of C. equisetifolia was studied in selected plantations of this species, located in three agro-climatic zones of the State. The data generated suggest that I. quadrinotata has the potential to reduce the growth of the trees significantly.

Keywords

Casuarina equisetifolia, Caterpillar, Indarbela quadrinotata, Insect Pests, Tamil Nadu

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R. F. Juliya , K. V. Sankaran , R. V. Varma

Abstract

A survey carried out in the Kerala part of the Western Ghats revealed high diversity of entomopathogenic fungi. A total of 401 fungi were identified from 341 insect cadavers during the study period of which 316 fungi were collected from moist deciduous forests (MDF) and 85 from teak plantations. Fungi were isolated from insects belonging to 10 orders with the highest isolations from the order Lepidoptera (120). Fifty eight species of fungi belonging to 24 genera were identified. Cadavers collected from MDF and teak plantations yielded 52 and 29 species respectively. Majority of the identified species belonged to the class Deuteromycotina. The overall abundance of entomogenous fungi was less in both MDF and teak plantations as indicated by rank abundance plots. Overlapping k-dominance curves showed the shift of dominance relative to species richness of fungi between the forest circles of both MDF and teak plantations. Rarefaction analysis for species richness showed that more species could be collected, if the sampling process had continued. The diversity of fungi was high in MDF compared to teak plantations. Diversity was high for northern and central forest circle of MDF and teak plantations respectively. Individual abundance and species abundance of fungi was high during the wet period. The fungi identified included commercially important and medically useful species.

Keywords

Diversity, Entomopathogenic Fungi, Western Ghats, Insect Cadavers

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R. V. Varma

Abstract

The hitherto unknown imago caste of Postelectrotermes nayari is described.

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R. F. Juliya ¹, V. V. Sudheendrakumar ¹, R. V. Varma ¹

Affiliations
1 Forest Protection Division, Kerala Forest Research Institute, Peechi 680 653, Thrissur, Kerala, IN

Abstract

Effect of four entomopathogenic fungi, Beauveria bassiana, B. brongniartii, Paecilomyces fumosoroseus and Metarhizium anisopliae, isolated from different host insects, was tested in the laboratory against the teak defoliator, Hyblaea puera (Cramer) (Lepidoptera: Hyblaeidae) to assess their virulence and efficiency. Five different concentrations, 2x10⁶, 4x10⁶, 6x10⁶, 8x10⁶ and 1x10⁷ conidia ml^-1were directly and indirectly applied onto third instar larvae of H. puera. All the four fungi tested under both application methods were pathogenic to H. puera with higher efficiency in direct application than indirect application. At 9 days after exposure, the mean per cent mortality obtained was 100, 93.02, 93.02 and 66.74%, respectively, for B. bassiana, B. brongniartii, P. fumosoroseus and M. anisopliae at the highest concentration of 1 x 10⁷ conidia ml^-1 in direct application. Mortality of the larvae varied according to the concentration of conidia, method of application and fungi. The lowest LC₅₀ (1.89 x 10⁶ conidia ml^-1) and LT₅₀ (91.18 hr) values obtained for B. bassiana in direct application showed that B. bassiana was more pathogenic to H. puera than the other three fungi.

Keywords

Beauveria bassiana, B. brongniartii, Entomopathogenic Fungi, Hyblaea puera, Metarhizium anisopliae, Paecilomyces fumosoroseus.

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R. F. Juliya ¹, R. V. Varma ¹

Affiliations
1 Forest Protection Division, Kerala Forest Research Institute, Peechi 680653, Kerala, IN

Abstract

Surveys for entomopathogenic fungi in the central forest circle of Kerala revealed the seasonal incidence of Beauveria bassiana in small pockets on Gargara mixta Buckton (Hemiptera: Membracidae) feeding on the leaves of Helicteres isora (Sterculiaceae) in the moist deciduous forests (MDF) at Vazhachal. Incidence of B. brongniartii on chrysomelid beetles (Coleoptera) feeding on teak leaves was also observed in small pockets in teak plantations. Infection was prevalent during post-monsoon months. The infection due to B. bassiana and B. brongniartii ranged from 36.8 to 100 and 45.5 to 100 per cent, respectively. The seasonal incidence of naturally occurring entomofungal pathogens, B. bassiana and B. brongniartii form small scale epizootics in nature under favourable environmental conditions. Such virulent pathogens can be exploited in pest control programmes.

Keywords

Entomopathogenic Fungi, Beauveria bassiana, Beauveria brongniartii, Gargara mixta.

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T. V. Sajeev ¹, V. V. Sudheendrakumar ¹, C. P. Biji ¹, M. Helen ¹, R. V. Varma ¹

Affiliations
1 Forest Protection Programme Division, Kerala Forest Research Institute, Peechi, 680 653, Trichur, Kerala, IN

Abstract

The economics of mass production of the nucleopolyhedrovirus of the teak defoliator, Hyblaea puera Cramer (Lepidoptera: Hyblaeidae) (HpNPV) using the laboratory-reared and field-collected (from teak plantations) host larvae was compared. The data were based on 7645 laboratory-reared (LR) larvae and 8925 field-collected (FC) larvae. The virus production was carried out using fifth instar larva inoculated with 1x10⁶ OBs (Viral Occlusion Bodies)/larva. The virus yield/larva in LR and FC larvae was 4.8x10⁸ and 3.6x10⁸ OBs, respectively. The virus productivity ratio in LR and FC larvae was 241 ± 55 and 178 ± 100.85 OBs, respectively. The cost of production of HpNPV per larva was higher in the case of LR (Rs. 0.82/larva) in comparison with FC (Rs.0.72). However, the cost of HpNPV required for spraying in one hectare at the rate of 1.63 x 10¹¹ OBs worked out to be Rs. 279 and Rs. 317 in the case of LR and FC, respectively. A marginal difference in the virus yield was found affecting the cost of the virus produced.

Keywords

Hyblaea puera, HpNPV, Mass Production, Nucleopolyhedrovirus, Teak Defoliator.

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K. R. Sasidharan ¹, R. V. Varma ²

Affiliations
1 Institute of Forest Genetics and Tree Breeding, Coimbatore, 641 002, Tamil Nadu, IN
2 Kerala Forest Research Institute, Peechi, 680 653, Kerala, IN

Abstract

The bark eating caterpillar, Indarbela quadrinotata Walker is a serious pest of Casuarina equisetifolia in Tamil Nadu State. Survey conducted in plantations located in different parts of the State resulted in detection of a potential strain of the biocontrol agent, Beauveria bassiana. Laboratory evaluation of B. bassiana against l. quadrinotata revealed that the fungal suspension at concentrations of 2 x 10⁶, 2 x 10⁷ and 2 x 10⁸ spores/ml was able to kill 66.67 per cent larvae. The fungus at a concentration of 4 x 10⁸ spores/ml gave 100 per cent mortality of the test larvae. The LC₅₀ at 240 hours was 1.6 x 10⁶ spores/ml and the LT₅₀ for the most effective concentration was 82.86 hours.

Keywords

Beauveria bassiana, Casuarina equisetifolia, Indarbela quadrinotata.

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P. R. Swaran ¹, R. V. Varma ¹

Affiliations
1 Division of Entomology Kerala forest Research Institute Peechi, Thrissur 680653, Kerala, IN

Abstract

Infectivity of the soil mixed conidia of the fungal pathogen Metarhizium anisopliae var. major was evaluated against the termite, Odontotermes guptai Roonwal and Bose under laboratory conditions. Four concentrations, viz., 0.8x10⁷, 1.2x10⁷, 1.6x10⁷ , and 2x10<SUP7 conidia/g soil caused complete mortality of the test termite in 192, 156, 132 and 120 hours, respectively. The LC⁵⁰ value at 12^th was calculated as 9.07x10⁶ conidia/g soil. The LT₅₀ value for the most effective dose was 86.84h. However, the test termites became less active within 48 hours of incubation.

Keywords

Eucalyptus, Melarhizium anisopliae, Odontotermes guptai, Termite.

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V. V. Sudheendrakumar ¹, T. V. Sajeev ¹, R. V. Varma ¹

Affiliations
1 Division of Entomology, Kerala Forest Research Institute, Peechi 680653, Kerala, IN

Abstract

The nucleopolyhedrovirus of the teak defoliator, Hyblaea puera Cramer (Lepidoptera: Hyblaeidae) (HpNPV) is a potential biocontrol agent of the pest. This paper describes a method to mass multiply HpNPV in situ in the field population of H. puera. The method is based on application of the virus suspension on young teak plantation infested with H. puera. An average yield of 4.8816 x 10& Polyhedral Occlusion Bodies (POBs) per fifth instar larva was obtained with this method. The advantage of this method of HpNPV production is that it is less expensive as it does not depend on host larval culture maintained in the laboratory.

Keywords

Hyblaea puera, HpNPV, Mass Production, Nucleopolyhedrovirus, Teak Defoliator.

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K. S. S. Nair ¹, Biju Babjan ¹, T. V. Sajeev ¹, V. V. Sudheendrakumar ¹, M. I. Mohammed Ali ², R. V. Varma ¹, K. Mohanadas ¹

Affiliations
1 Division of Entomology, Kerala Forest Research Institute, Peechi 680 653, Kerala, IN
2 Division of Plant Pathology, Kerala Forest Research Institute, Peechi, IN

Abstract

In the year 1993, a 100 tree plot in a 17 year old teak plantation at Nilambur in Kerala was experimentally protected from Hyblaea puera Cramer, a serious defoliator of teak plantations, using a naturally occurring baculovirus (HpNPV) reported earlier from this pecies. During the year, there were four major peaks of defoliator infestation from March to June. One-time foliar application of a crude preparation of HpNPV at the rate of 1x10⁵ POB/ml of the spray fluid, at the earliest sign of each infestation, gave 70-76 per cent protection of foliage during the first two infestations. A reduced foliage protection of 33-43 per cent obtained during the third and fourth infestations was attributable to occurrence of rain soon after application of the spray. In protected trees, the basal area increment was enhanced by 41 per cent, indicating the efficacy of HpNPV as a biocontrol agent against the teak defoliator.

Keywords

Baculovirus, HpNPV, Hyblaea puera, Teak Defoliator.

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M. I. Mohamed Ali ¹, R. V. Varma ¹

Affiliations
1 Division of Plant Pathology and Entomology, Kerala Forest Research Institute, Peechi 680 653, IN

Abstract

Two common methods to test the efficacy of fungal isolates against insect pests are direct application of fungal spores on to the insect or allowing insects to feed on leaves treated with fungal spores. In the above two methods, it was often difficult to quantify the exact lethal concentration in terms of spores/cm² leaf area. In the present study, a leaf surface bioassay technique has been standardised using two fungal pathogens - Paecilomyces farinosus (Holm: Fr) and F. fumosoroseus (Wize) Brown & Smith, both isolated from the pupae of Eligma narcissus Roth, a serious pest of Ailanthus triphysa Roxb.

Keywords

Eligma narcissus, Paecilomyces farinosus, Paecilomyces fumosoroseus, Ailanthus triphysa.

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