The colour of your bunch covers may help control banana rust thrips
Banana rust thrips continue to be a significant pest for banana growers with levels of damage increasing in recent years. The thrips cause damage by feeding on the skin of immature banana fruit which causes reddish-brown marks. Growers are reporting that even fruit with low levels of damage are not meeting market specifications.
So what role does the colour of bunch covers play in rust thrips damage? Interest amongst researchers was sparked after previous work had shown that rust thrips respond differently to different coloured sticky traps. This prompted researchers to have a look into the effect that different coloured bunch covers have on thrips damage. The aim is to find non-chemical control methods as part of an Integrated Pest Management (IPM) strategy.
Initial trial results are encouraging and do show a difference in the level of damage caused by thrips depending on the colour of the bunch covers used. In this trial no chemical treatment was applied to the bunch after bell injection and the bunch cover was applied as per commercial timing. Orange, yellow and purple bunch covers showed damage above commercially acceptable levels in this scenario. The best performer was a paper bunch cover with a polyethylene ‘cloth’ liner. Light blue and white also produced similar low levels of damage compared with some other colours.
Finger length, colour and bloom were also assessed with results indicating that bag colour has no significant effect on these fruit quality attributes.
Based on the initial trial results growers should consider using bunch cover colours that have a low thrips damage rating. This coupled with standard insecticide treatments applied at bunch covering should provide the best level of control. Further work is underway to expand these results by testing new colour and liner combinations. Recommendations of the latest trial will be available to growers in the coming months.