Control of greyback canegrub by manipulating adult behaviour : SRDC final report BSS205

Abstract

In the Burdekin, early-planted and early-cut cane is more frequently damaged by greyback canegrub than other classes of cane. Cane height is important in attracting egg-laying greyback beetles and early-planted and early-cut cane is generally the tallest cane on Burdekin farms during the period of beetle flight. In this project, the effect of trap crops (tallest sections of cane or other crops) on damage to surrounding cane was determined. These trap crops were created by planting cane 'early', harvesting sections of blocks in early harvest rounds, planting forage sorghum, applying high rates of N fertiliser, and selective irrigation. In the 1999- and 2000-harvest seasons, early-plant and early-harvest or ratoon trap crops reduced grub numbers in adjacent blocks by 70-100%. The single critical factor for successful trap crops was the height of the crop relative to adjacent blocks. Cane cultivar and fertiliser rate were not important in the success of trap crops. Beetle flight determined by light-trap catches in the summers of 1998-1999 and 1999-2000 generally had a single identifiable peak. Dispersal of greyback beetles was difficult to quantify.