Survivability of Lepidiota mansueta (Coleoptera: Scarabaeidae) Grubs under Different Soil Orders of Assam, India
Mrinmoy Das
College of Agriculture, Assam Agricultural University, Jorhat-785013, India.
Badal Bhattacharyya *
Department of Entomology, College of Agriculture, Assam Agricultural University, Jorhat-785013, India.
Sudhansu Bhagawati
Department of Entomology, College of Agriculture, Assam Agricultural University, Jorhat-785013, India.
Shimantini Borkataki
Department of Entomology, College of Agriculture, Assam Agricultural University, Jorhat-785013, India.
Anjuma Gayan
Department of Soil Science, College of Agriculture, Assam Agricultural University, Jorhat-785013, India.
Dhruba Jyoti Nath
Department of Soil Science, College of Agriculture, Assam Agricultural University, Jorhat-785013, India.
*Author to whom correspondence should be addressed.
Abstract
The survival of the third instar grubs of Lepidiota mansueta under four different soil orders of Assam was investigated in the Soil Arthropod Pests Laboratory and Bio-fertilizer Laboratory, Assam Agricultural University, Jorhat during 2012-17. A total of 30 grubs were reared for each of the soil orders in ambient laboratory conditions (temperature: 28±2o C & Humidity: 70-80%). Among the four different soil orders, grubs were successfully reared up to adult stage in both surface and subsurface soil of Entisols and Inceptisols. Survival of grubs was recorded in surface (214.46 days) and subsurface (212.20 days) soil of Entisols with adult emergence of 73.33% and 86.66% respectively, whereas in case of Inceptisols survival of grubs was found to be 210.03 and 205.67 days with adult emergence of 5.00% and 11.67%, respectively. The maximum organic carbon (0.89%), pH (6.48), soil microbial biomass carbon (289.70 mg/ kg), and sand (67.20%) were recorded in case of Entisols which exhibited a loamy sand texture. However, not a single grub could survive under Alfisols and Ultisols, indicating the strong effects of soil physicochemical properties on survival of the grubs. The findings of the present research will help developing predictive risk models and subsequent management of this pest.
Keywords: Alfisols, Entisols, Inceptisols, scarabaeids, Ultisols, white grubs