By Tegan Cavallaro on behalf of the DPI Banana Extension team

Banana bunch pests, including vertebrate pests (e.g. birds and bats), insects (e.g. banana rust thrips, banana flower thrips, banana scab moth) and fruit fungal diseases (e.g. sooty blotch and fruit speckle), all impact fruit quality and can increase on-farm waste, ultimately impacting your bottom line. Hot, wet, humid conditions and fast plant growth can make managing these pests a challenge.

Effective bunch pest management involves a combination of strategies, including bell injection, bagging, bunch spraying, and ground or stem applications, with pesticide resistance management carefully considered across these practices.

Bell injection

• Timing of bell injection in the upright position is crucial, particularly for scab moth control. At this time of year when plants are growing quickly, aim to target upright bells by injecting blocks every 3–4 days before they tip over.
• Volume of bell injection is important, especially for flower thrips control.
• Injection position – Correct position of the bell injection is in the top half to one third of the bell just below the swelling point.

Bagging

• Timing – For growers with bird and bat pressure, early bagging (bells) with either a bag or liner significantly reduces scratching and also reduces rust thrips damage.
• Tying method – Leaving a hole or ‘flue’ in the top of the bunch cover is thought to increase air flow through the bag and help reduce fruit speckle (however it is not a sufficient treatment on its own).
• Type of bag – Paper bunch covers may reduce fruit fungal issues, trial results are promising but not conclusive and may vary depending on disease pressure.

Bunch spraying

• Coverage – Current registered chemicals require good coverage to be effective.
• Equipment – A range of equipment is used to apply bunch sprays and both air assisted and hydraulic options can provide good coverage.
• Training – Staff training is critical to ensure good coverage and correct volume is constantly applied to bunches.
• Continual improvement – Growers and commercial providers continue to innovate their spray systems to achieve good coverage in a timely and effective way.

Ground and stem application

• Chemical control for rust thrips can be directed at soil dwelling pupae and adults and larvae on the plant to reduce population levels.
• Timing – consider timing applications ahead of peak insect pressure. Ground sprays may take 6-7 weeks compared to stem treatments (2-3 weeks) before full effects are observed on rust thrips populations.

Resistance management

• There are limited chemical actives available to control bunch pests so chemical stewardship is IMPORTANT! Repeated use of chemicals with the same mode of action, mixing of insecticides and or/application of sub-lethal doses can increase the risk of resistance developing.

Chemical reminders

• Always check product labels as formulations can differ in mixing and application rates.
• If using spinetoram, the mixing rate on the permit (PER87198) for bell injection differs from the label rate for bunch spraying.
• Group 4A chemicals (e.g. imidacloprid) can lead to mite flares. Limit the use of these chemicals at times of the year when environmental conditions are favourable to mite flares (e.g. hot dry periods).
• Mixing products with different modes of action is not recommended and limits options for rotation to manage resistance.
• Regularly calibrate equipment and check application techniques.
• Check labels for storage and mixing requirements.
• It’s important to always follow label instructions. Off-label use can be unsafe for workers and crops, ineffective, and may breach legal regulations.