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Timing of bunch cover application and its effect on bunch pests

About the trial

Far North Queensland growers have reported that the biggest issues affecting their yield and quality are birds/bats and banana rust thrips.

Bagging bunches is an important practice that protects developing fruit from leaf rubbing, banana rust thrips, and birds/bats. This trial compared the effect of timing of bunch cover application, comparing early bagging (applied to a newly
emerged bell before hands are visible) to traditional bagging (at pruning) and examined the effect on damage caused by bunch pests.

Main banana bunch pests assessed in the trials
Timing of traditional bagging treatment used for the trial
Timing of traditional bagging treatment used for the trial
Timing of early bagging treatment used for the trial
Timing of early bagging treatment used for the trial

Key findings

Birds and bats

  • Bunches that were bagged ‘early’ had a significantly lower number of hands damaged by animal scratches (0.37%) compared to those that were bagged at ‘traditional’ timing (57%).
Chart showing the percentage of hands with bird and/or bat damage for the two timing treatments for applying bunch covers. Bagging bells early (left column) had significantly less hands with damage compared to bunches bagged at pruning/traditional timing (See images above).
Image showing damage caused by birds and/or bats by puncturing and scratching the fruit.

Banana rust thrips

  • Bunches that were bagged early had a significantly lower number of fingers with banana rust thrips damage (3%) compared to traditional bagging (20%).

  • Tying a bag and/or liner early provides a barrier to banana rust thrips moving down the stalk into the bunch (see image below).

Chart showing the mean percentage of assessed fingers with banana rust thrips damage for the two timing treatments for applying bunch covers. Bagging bells early (left column) had significantly less fingers with damage compared to bunches bagged at pruning/traditional timing.
Image shows demarcation of banana rust thrips feeding marks on bunch stalk. This is the point at which the liner was tied.

Banana flower thrips

  • As expected, early bagging had no significant effect on banana flower thrips damage, as control is mainly achieved through chemical application via bell injection. 

Banana scab moth

  • Not enough data was collected for banana scab moth damage. Only a few bunches had damage, indicating low pressure at the time of the trial. 

For information about this trial contact:

The Better Bananas team at betterbananas@daf.qld.gov.au. 

This trial has been undertaken as part of the National Banana Development and Extension Program (BA19004) which is funded by Hort Innovation, using the banana industry research and development levies and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture. The Queensland Government has also co-funded the project through the Department of Primary Industries. 

Horticulture Innovation Australia (Hort Innovation) and the Queensland Government make no representations and expressly disclaim all warranties (to the extent permitted by law) about the accuracy, completeness, or currency of information in this factsheet. Reliance on any information provided by Hort Innovation and the Queensland Government is entirely at your own risk. Hort Innovation and the Queensland Government are not responsible for, and will not be liable for, any loss, damage, claim, expense, cost (including legal costs) or other liability arising in any way (including from Hort Innovation and the Queensland Government or any other person’s negligence or otherwise) from your use or non-use of this factsheet or from reliance on information contained in the material or that Hort Innovation and the Queensland Government provides to you by any other means. 
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