J. Exp. Zool. India Vol. 16, No. 2, pp. 505-508, 2013 ISSN 0972-0030

SPECIES COMPOSITION OF WHITE GRUBS IN RAINFED ECOSYSTEM OF , INDIA

P. S. Tippannavar and R. R. Patil Department of Agricultural Entomology, University of Agricultural Sciences, Dharwad-580 005, India e-mail: [email protected] (Accepted 8 June 2013)

ABSTRACT – Studies were carried out in district of Karnataka during 2011 and 2012 to know the species composition of scarabaeids and their abundance in relation to soil moisture and cropping pattern. Four species of root grubs viz., Holotrichia fissa Br., Holotrichia serrata Fab. and Anomala bengalensis Blanch. and Anomala ruficapitata Burmeister were recorded during study period. Holotrichia fissa was economically important and found in large numbers as compared to other species in Hattarwat village of Chikkodi taluka on neem and ber. The adult beetles were attracted with the help of light source. Adult emergence commenced with the onset of pre-monsoon showers from 14th meteorological standard week (MSW) (April) and continued up to 22nd MSW (May) with peak during 16 to 20th MSW (April-May). Almost all the major kharif crops grown in this area like groundnut, maize, sorghum, paddy, chilli, soybean and cotton were infested by this pest. Key words : White grubs, rainfed ecosystem, species.

MATERIALS AND METHODS INTRODUCTION Monitoring of adults was carried out from 9th MSW “White grubs” also called as “root grubs” feed on (March) and continued upto 22nd MSW (June) during both roots in their larval stage, while adults called as “chaffer the years (2011 & 2012) to assess the species composition beetle” or “May-June beetles”, feed on leaves of different in rainfed ecosystem of Hattarwat. Hattarwat village is host plants. Sugarcane root grub infestation has been situated in Chikkodi taluka of Belgaum district. It is part reported throughout the country. The scarabaeid fauna of Deccan Plateau in hot semi – arid eco region situated of the Indian sub region is very rich and diverse, but it is at 15o North and 74.06o East and located 20 km away yet to be explored (Mishra and Singh, 1999). Gupta and from on NH-4. Adult beetles were collected Avasthy (1956), reported about 1500 species of root grubs by hand picking and shaking the twigs of host plants viz., on economically important agricultural and horticultural neem (Azadirachta indica A. Juss.) and wild ber crops in different parts of the country including white grub (Zizyphus spp.) located on bunds and nearby cultivated pest of sugarcane. However, in recent times root grub fields using torch as a light source. The adults so collected problem is becoming widespread in different talukas of were brought to the laboratory and cultured in field cages Belgaum district of Karanataka state. by creating suitable conditions for further development. Different species of root grubs have similar pattern Few adults of various species were preserved in 70% of life cycle that depends upon many abiotic and biotic ethyl alcohol for identification. During the monsoon period factors prevailing at the time of emergence and egg laying. (June onwards) the population density viz., grub load in Adult beetles emerge from the soil during April-June, after one square meter area in different crops was recorded the receipt of first summer showers (Veeresh, 1977). following destructive sampling. Five such spots were Holotrichia species become active with the onset of pre- selected in each field and average was worked out. Finally, monsoon rains; if the rains are delayed, the emergence population density of root grub was correlated with soil will also be delayed (Yadava and Sharma, 1995). Root moisture. grubs damage roots of many crops to the tune of 70-80 RESULTS AND DISCUSSION per cent. The genus Holotrichia includes the most important pest species on many cultivated crops. Monitoring studies over two years in rainfed Holotrichia serrata is endemic in Athani, , ecosystem of Hattarwat village of Chikkodi taluka Chikkodi, and talukas of Belgaum district. revealed the presence of four species of root grubs viz., H. fissa, H. serrata, A. bengalensis and A.