Guava Fruit Fly

Symptoms by part

Causes

• Presence of ripening fruit that attracts egg laying females.
• Warm temperatures that speed up the life cycle of the fly.
• Lack of physical barriers to prevent flies from reaching the fruit.

Could be confused with

• Fungal fruit rot · Fungal rot usually starts as a surface discoloration or fuzzy growth, whereas fruit fly damage begins with a puncture hole and internal tunneling.
• Bird damage · Birds leave large, jagged tears or missing chunks of fruit, while fruit fly damage consists of tiny, pinprick sized holes.

Treatment

1. Pick and destroy all infested fruit on the tree immediately to stop the larvae from completing their cycle.
2. Collect and dispose of any fallen fruit from the ground daily so larvae cannot burrow into the soil.
3. Bag individual fruits with fine mesh or paper bags while they are still small to prevent flies from landing on them.
4. Use spinosad as a bait spray on the foliage to target adult flies, follow the label.

Without chemicals

• Use fine mesh fruit bags to physically exclude the flies.
• Clear away all dropped fruit from the soil surface to break the life cycle.
• Prune the tree to improve airflow and visibility, making it easier to spot and remove infested fruit.

Chemical options

• Spinosad, apply as a bait spray to the foliage to target adults, follow the label.

Preventing it

• Bag fruit early in the season before it begins to ripen.
• Keep the area under the tree clean of debris and fallen fruit.
• Harvest fruit as soon as it reaches maturity to reduce the window of vulnerability.

When to act

Act as soon as you notice tiny puncture marks on your fruit. If the infestation is widespread and you cannot manage the fruit drop, remove the affected crop entirely to protect future seasons.

Questions people ask

Can I eat fruit that has been stung by a fruit fly?

It is best to discard it, as the puncture marks allow bacteria and fungi to enter, which can cause the fruit to rot quickly and potentially harbor larvae.

Will the tree survive a severe infestation?

Yes, the tree itself will survive, but you will likely lose the entire season of fruit production if the infestation is not managed.