TRAP CROPS FOR THE MANAGEMENT OF GREYBACK CANEGRUB IN THE BURDEKIN

In the Burdekin, early-planted and early-cut cane is frequently damaged by greyback canegrub (Dermolepida albohirtum). Cane height is probably 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. The use of trap crops (tallest sections of cane or other crops) to reduce damage to surrounding cane was studied. Planting sections of cane ‘early’, harvesting sections of blocks in early harvest rounds or planting forage sorghum all created trap crops. In the 1999–2001 harvest seasons, trap crops created by early-planting and early-harvesting reduced the numbers of grubs in adjacent blocks by 50–100%. The single determinant for successful trap crops was the height of the crop relative to adjacent blocks. The greater the difference in height between the trap crop and adjacent cane, the greater the difference in grub numbers between cane blocks. Cultivar was not important in the success of trap crops. We discuss and provide examples of how the use of one or more methods of trap cropping complements existing management strategies for greyback canegrub.