A fruit that looks sound outside but has small white larvae inside, or soft spots and early fruit drop under the tree: these are signs of fruit flies, among the most damaging pests of fruit and vegetables on farms and in home gardens.
This guide explains the types of fruit flies and the signs of infestation, how to monitor them with traps, and how to control them and stop them coming back, with practical steps for the farm and the garden.
Common types: Mediterranean fruit fly, peach fruit fly and vegetable flies.
Crops affected: citrus, peach, mango, guava, fig, grape, tomato, cucumber, melon and others.
Sign: a tiny puncture on the skin where eggs were laid, a soft fruit, larvae inside the pulp and fruit drop.
Common mistake: leaving fallen fruit under the trees. It is the source of the next generation.
Rule: monitor with traps, collect and dispose of infested fruit, and treat early before egg laying while respecting the safety interval.
What are fruit flies?
Small insects a little bigger than the house fly, with a speckled body and banded wings. The female lays eggs under the fruit skin, the larvae hatch and feed on the pulp, spoiling it and speeding up rot. Several generations develop each year in warm weather.
Signs of infestation
- Small dark specks on the skin where the female punctured it.
- Soft or discoloured patches on the fruit.
- Small white larvae inside the pulp when the fruit is cut.
- Fruit dropping before it ripens.
- Small flies hovering around ripe fruit at midday.
- A fermenting smell when it rots.
Damage
- A large loss of crop and lower fruit quality.
- Fruit rejected in markets and for export because of infestation.
- Secondary rot from fungi and bacteria.
- Spread of infestation from farm to farm through fruit and crates.
- Higher control costs the later you act.
How do you monitor the flies before damage appears?
- Traps: attractant traps with pheromone or protein bait, spread through the field from the start of the season.
- Weekly checks: count and record the flies in the traps. A rise in numbers is the signal to begin control.
- Fruit checks: cut samples of fallen and ripe fruit.
- Timing: treat before egg laying, not after larvae appear inside the fruit.
An integrated control plan
- Farm hygiene: collect fallen and infested fruit daily or every few days and dispose of it in sealed bags away from the farm.
- Mass trapping: to cut males and females and reduce mating.
- Spot bait spraying: applied to parts of the trees, not to the fruit, according to the label.
- Treatment with a suitable insecticide when numbers rise, respecting the safety interval before harvest.
- Harvest on time: do not leave ripe fruit on the tree.
- Cover or bag the fruit in small gardens and on a few trees.
- Cultivate the soil surface under the trees to expose pupae to the sun and predators.
Common mistakes
- Leaving fallen fruit under the tree.
- Starting control after larvae appear inside the fruit.
- Spraying insecticide on fruit close to ripening without respecting the safety interval.
- Relying on a single product all season.
- Ignoring neighbouring farms and infestation sources around you.
- Moving infested fruit between farms in dirty crates.
How to stop them coming back
- Clean the farm after harvest of any remaining fruit.
- Keep monitoring with traps all season.
- Coordinate control with neighbouring farms.
- Disinfect harvest crates and fruit stores.
- Prune the trees for better airflow and easier spraying.
- For other sucking pests, see Sucking Insects on Farms and Gardens.
Products from the Orkida Store
We start with hygiene and monitoring with traps, then treat when needed. We advise following the label dose and the safety interval.
- Evital 50% SP Thiocyclam Insecticide 1 kg – Whitefly & Leaf Miner: a semi-systemic thiocyclam insecticide whose label lists fruit fly, whitefly, thrips and leaf miners on vegetables and fruit, with a safety interval written on the label.
Frequently asked questions
Is an infested fruit fit to eat?
It is better to discard it. The pulp spoils quickly and may carry secondary rot.
When do I start control?
When flies appear in the traps and before the fruit begins to ripen, not after larvae appear.
Are traps enough on their own?
They help with monitoring and reducing numbers, and are completed by hygiene and treatment when needed.
How do I dispose of infested fruit?
In tightly sealed bags away from the farm. Never leave it exposed.
Do fruit flies attack vegetables?
Yes, they attack tomato, cucumber, melon and others.
Do they appear in winter?
Their activity drops in winter and rises in the warm months.
If you are not sure which fly you have, or the infestation is large or keeps coming back, visit your nearest Orkida branch with a photo or a sample and we will point you to the right product.