Soil moisture vs. vertical movement of late instar white grubs, leucopholis lepidophora blanchard infesting arecanut

Impact of soil moisture on the vertical upward movement of arecanut white grub, Leucopholis lepidophora (Blanchard) was evaluated in the soil profile in the dry season, between December and January 2013 and 2014, to standardise a methodology for its management with drainage/flooding. Results indicate that the filling drainages with water by plugging two ends + flooding the field for eight days were the most effective. This will enable bringing the larvae to top layer of 15 cm depth (1.83 larvae/tree base and 2.00 larvae/tree base, respectively). However, in control, where no effort was made to increase the soil moisture, larvae were not found in top layer. Thus, it is suggested to increase the soil moisture by flooding for taking up any management activity during this part of year. This helps in reduction of white grub population, which otherwise remain deep in soil (>60 cm depth), feed roots and continue to cause damage. This can be used as an important strategy in integrated pest management of white grubs in areca nut gardens.