Trap cropping was developed for the Burdekin district as part of an integrated control program for greyback canegrub. It is effective where the topography is flat but less effective in other areas with broken topography. Trap cropping aims to manipulate the harvesting and planting sequence to attract egg-laying beetles to specific cane blocks.
Trap cropping works by taking advantage of cane beetles’ attraction to early-harvested cane that is significantly taller than surrounding cane. The greater the height difference between a trap crop and surrounding cane, the more effective this strategy is likely to be.
Early planted cane blocks
Early planted cane blocks can focus grub pressure into early-planted fallow cane which has been treated with insecticide. This helps to reduce the grub pressure on later planted cane and ratoons. Early cut seed cane blocks are suitable.
Ratoon trap crops
Ratoon trap crops can be created by early-harvesting either whole blocks or sections of blocks. Older, low yielding ratoons due to be ploughed out can be early-harvested, then cultivated out in February-March to kill grubs.
Younger, higher yielding ratoons can still be used as trap crops by early-harvesting then treating with imidacloprid to kill any subsequent infestation of grubs.
Trap crops should be in close proximity to sections of the farm known to suffer grub damage. Use a minimum of eight rows for an effective trap crop. Usually a number of trap crops are needed, with the number increasing if the terrain is hilly.
These graphs show that greyback canegrubs are attracted more to taller cane
Forage sorghum also attracts egg-laying beetles and can be used as a trap crop. Cultivate the sorghum out during February to March to kill grubs.