Biol. Control, 19(2): 197-200.2005) (J. Research Note

Laboratory evaluation of Beauveria bassiana (Balsamo) Vuillemin against quadrinotata Walker (: ) - a key pest of equisetifolia L. in Tamil Nadu

K. R. SASIDHARAN and R. V. VARMA 1 Institute of Forest Genetics and Tree Breeding Coimbatore 641002, Tamil Nadu. India Email: [email protected]

ABSTRACT: The bark eating caterpillar, Walker is a serious pest of Casuarina equisetifolia in Tam.i1 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 I. quadrinotata revealed that 7 8 the fungal suspension at concentrations of 2 x 10', 2 X 10 and 2 x 10 spores! rul was able to kill 66.67 per cent larvae. The fungus at a concentration of 4 x 108 sporest rul gave 100 per cent m.ortality of the test larvae. The LCso at 240 hours was 1.6 x 10' sporesl ml and the LT50 for the m.ost effective concentration was 82.86 hours.

KEY WORDS: Beauveria bassiana,Casuarina equisetifolia, Indarbela quadrinotata

The bark caterpillar, Indarbela quadrinotata Though chemical insecticides have been Walker is a polyphagous pest attacking several tested against the bark caterpillar (Mathew, 1997; forest trees belonging to families, Bombacaceae, Singh and Verma, 1998), use of chemical insecticides Euphorbiaceae, Leguminosae, Loganiaceae, has limitations in a forest ecosystem. There are Myrtaceae, Rhamnaceae and Verbenaceae and many reports on incidence of the white muscardine also cause damage to fruit trees and bushes (Sandhu fungus, Beauveria bassiana (Balsamo) VuiHemin and Khangura,1979; Bhargavaand Kumawat,1988). on pests of forest trees (Arshad and Hafiz, l.quadrinotata is a serious pest of Casurina 1983; Mohamed Ali and Sudheendrakumar, 1991; equisetifolia in Tamil Nadu. The larva feeds on the Mohamed Ali et al., 1991), The efficacy of the outer as well as inner bark of trees. The pest usually fungus, B. bassiana on various forest insect pests attacks Casuarina trees of 2 years and above age has also been reported (Mohamed Ali et aI., 1991). and the mortality of trees ranges from 3 to 5 per During the course ofthe survey on natural enemies cent annually. of I. quadritlotata, in C. equisetifolia plantations

I Kerala Forest Research Institute. Peechi 680 653. Kerala. India SASIDHARAN and VARMA

at Neyveli area of Tamil Nadu, large-scale morta1ity were provided to the larvae for feeding. Three of the host larvae was found due to the infection of replications, each with 5 larvae were used for the the fungal pathogen. experiment. Using a pipette, 3ml of the spore suspension having the above mentioned spore The cadavers of the bark caterpillar, concentrations were applied on to the larvae. Sterile I.quadrinotata. affected by the fungal pathogen distilled water was applied on to the larvae were collected and properly washed with sterile maintained as control. The experiment was distilled water. They were kept in Petri-dishes conducted at room temperature, 27±I°C and relative containing moist filter paper to facilitate fungal humidity 76± 4 per cent. Fresh Casuarina twigs growth. The fungus was isolated in Potato Dextrose were provided to the larvae on every third day for Agar (PDA) medium and was identified as feeding. The larval mortality was recorded at 12 Beauveria bassiana. Later on, cultures were made hour duration, up to l(yh day. The proportion of in Petri-dishes, using Saburaud Dextrose Agar mortality obtained at each concentration was (SDA) medium. The full-grown cultures after a week worked out and their significance tested, using Z­ were crushed in sterile distilled water and filtered test. The time-mortality relation was analyzed using through sterile muslin cloth to eliminate the medium. Probit analysis (Finney, 1972). A software POLO­ This formed the stock spore suspension and by PC (© Le Ora Software, 1987), based on Finney adding sterile disti11ed water made the required spore (1972) was used for the analysis of the replication­ concentrations. The spore counting was made wise data. using a standard haemocytometer. 6 7 Out of the four concentrations '- 2 x 10 , 2xl0 , Spore suspension of B: bassiana in sterile 2x 108 and 4x 1 08 spores/ ml tested, the first three distilled water, at four concentrations - 2x 1()6 spores/ gave 66.67 per cent mortality of larvae by 10,h day ml, 2xI07 spores/ ml, 2xl08 spores/ ml and 4xlOS after the application of spore suspension and thus, spores/ ml were tested for efficacy, on I. all these three concentrations were comparable in quadrinotata. Five bark eating caterpillars terms oflarval mortality. The highest cor.centration (approximately six weeks old) were introduced into tested, i. e., 4x lOS gave 100 per cent larval mortality. Petri-dishes of9cm diameter lined with filter paper. The mortality at this concentration was found to Fresh twigs of Casuarina, washed in distilled water be significant compared to lower concentrations

.~ 120 '3... 100 s= 80 -=...QJ 60 I-+-Tl QJ Q. 40 ~ ---T2 -i 20 :; --1k- T3 S 0 u= I-T4 1 2 3 4 5 6 7 8 9 10 Day

Tl- 2xl06 Spores/ml T3- 2xlOS Sporeslml T2- 2xl07 Spores/ml T4- 4xlOS Sporeslml Figurel. Time-mortality relation

198 Laboratory evaluation of B. bassiana against 1. quadrinotata

tested. No larval mortality was observed in the Bhargava, M. C. and Kumawat, S. R. 1988. Management of bark eating caterpillar, Indarbela quadrinotata control. The Leso values worked out at 240 hours was 1.6 x 1 ()6 sporesl ml. The median lethal time Walker on Ber(Zizyphus mauritiana Lam.) trees by (LTso) for the most effective dose (4 x 108 sporesl insecticides. Journal ofTree Science, 7: 33-36. ml) was found to be 82.86 h. Finney. D. J .l972. Prahit Analysis. Cambridge University In all the concentrations tested, the mortality Press, London. 318pp. of the larvae started from the 2nd or 3rd day after the inoculation (Fig.l). The infected larvae became Mathew, G 1997. Management of the bark caterpillar sluggish and stopped feeding. The normal brown Indarbela quadrinotata in forest plantations of Paraserianthes falcataria. KFRI Research Report colour of the larvae slowly changed to pale pink. No. 122. Kerala Forest Research Institute, Peechi. The dead larvae became somewhat stiff and 24pp. mummified: Fungal mycelia were observed on the th inter-segmental membranes either on 4th or 5 day Mohamed Ali, M. Land Sudheendrakumar, V. V. 1991. after inoculation and subsequently the entire larva Possible use of microbial pathogens against was covered by white, fluffy mycelial growth. pests, pp. 93 - 99. In: Proceedings of the International Teak Sympopsium conducted at B. bassiana is highly pathogenic and has over Thiruvanathapuram. 700 recorded host species (Moore and Prior, 1993). Rajak et al. (1993) observed that. B. bassiana caused Mohamed Ali, M. I., Varma R. V. and Sudheendrakumar, a maximum mortality of 96 percent to 2nd instar larvae V. V. 1991. Evaluation of microbial pathogens for of the teak defoliator, H. puera with a spore biocontrol against important insect pests of Ailanthus concentration of 1 xl ()4 conidial m), They also and Teak. KFRI Reserch Report No. 72. Kerala Forest reported that B. bassiana caused 100 per cent Research Institute, Peechi. 44 pp .. mortality of 2nd instar larvae of the teak skeletonizer, Eutectona machaeralis, with a spore concentration Moore, D. and Prior. C. 1993. The potential of mycoinsecticides. Biocontrol News and 1nfonnation. ofOAx 104 spores/mL Mohamed Alietal. (1991) 14: 31N - 40N. studied the efficacy of B. bassiana against larvae of webworm and Ailanthus (Atteva fabriciella) Rajak, R. Agarwal, G P.. Khan, A R. and Sandhu. S. 2 c., found that, the fungus at concentrations of Ixl0 , S. 1993. Susceptibility of teak defoliator (Hyblaea Ixl()3, Ixl04 and 1 xlO~sporesi ml could result in larval puera Cramer) and teak skeletonizer (Eutectona mortality of 26.6. 40, 53.3 and 80 per cent. machaeralis Walker) to Beauveria bassiana (Bals.) respectively, at 96 hours after application. The Vuill. Indian Journal of Experimental Biology, 31: present study has shown that a much higher spore 80-82. concentration of B. bassiana is required to achieve maximum kill of the bark-eating caterpillar, I. Sandhu. G. S. and Khangura, J. S. 1979. Chemical control quadrinotata. of bark eating caterpillar on guava in Punjab. Pesticides, 13: 32 - 34. REFERENCES Singh. R. and Verma, T. D. 1998. Incidence and Arshad. M. and Hafiz. I. A. 1983. Field incidence of control of Poplar stem borer, Apriona cinerea Beauveria bassiarw (Bats.) Vuill. on Indarbela Chevro1et (Cerambycidae. Coleoptera) in Paonta quadrinotata Wlk. (Pseudarbelidae. Lepidoptera). Valley of Himachal Pradesh. Indian Forester, Bulletin ofZoology, 1: 11- 16. 124: 556 - 560.

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