How do I stop wasps ruining my fruit?

Wasps switch from hunting insects to seeking sugar in late summer, when the colony stops rearing brood, and they become a serious nuisance around ripe fruit for about six weeks. In most cases they are not the first cause of damage — a bird peck, a rain split or a codling moth exit hole gets there first, and the wasps enlarge it. That is why the effective measures are mostly about the original wound and the fallen fruit rather than about the wasps themselves.

Safety

What you'll need

• A bucket and a way to dispose of fallen fruit
• Fine mesh bags or muslin for individual fruit (optional)
• Wasp traps (optional)
• Fine netting (optional)

Step by step

1. Clear fallen and damaged fruit, daily.Rotting windfalls are what draws wasps into the garden and keeps them there. Picking them up every day in late summer makes a genuine, noticeable difference.
2. Deal with the original wound source.Bird pecks, split fruit after rain, brown rot and codling moth exit holes all provide the opening. Netting, mulching for consistent moisture and codling control all reduce wasp damage indirectly and effectively.
3. Pick fruit slightly early where the variety allows.Pears, plums and early apples can be picked a little firm and finished indoors. A week earlier is often the difference between a crop and a wasp buffet.
4. Bag individual fruit or bunches on high-value crops.Fine mesh drawstring bags, muslin, or organza favour bags over grape bunches, figs and choice plums. Fiddly, and the only thing that reliably works on grapes.
5. Net where you can, with fine mesh.Standard bird netting does not exclude wasps. Fine insect mesh does, over a frame, and it keeps birds off at the same time.
6. Site any traps well away from the fruit.Sweet traps catch a lot of wasps and also attract more into the garden. Put them at the boundary, upwind if possible, not next to the tree you are protecting.
7. Cover bins, compost heaps and juicing waste.Open compost with fruit waste in it is a wasp magnet all through late summer. Cover the heap, bury fruit waste under other material, and keep bin lids shut.
8. Do not tackle a nest yourself.If there is a nest in the garden causing a real problem, use a pest control professional. Wasps also eat huge numbers of aphids and caterpillars for most of the year, so a nest that is not causing a problem is worth leaving alone.
9. Pick early in the day.Wasps are slower in the cool of the morning. Picking then is easier and less confrontational than at three in the afternoon.
10. Move calmly and never swat.Swatting releases an alarm pheromone that recruits others. Move away slowly instead.

Tips

• The wasp problem lasts roughly six weeks in late summer, and then the colony dies out with the first frosts. It is a season, not a permanent condition.
• Wasps are significant predators of aphids and caterpillars for most of the year, and the same colony that is a nuisance in September was useful in June.
• A rotting windfall under a tree can hold dozens of wasps. Ten minutes a day with a bucket is the single most effective measure there is.
• Wasp-damaged fruit rots quickly. Pick it, cut out the damage and use it straight away rather than storing it.
• Fine mesh bags over individual figs and grape bunches also keep birds off and are reusable for years.

Common mistakes

• Hanging sweet traps in the fruit tree — You attract far more wasps to the exact place you are trying to protect. Traps go at the boundary, well away from the crop.
• Leaving windfalls to rot under the tree — It is a permanent food source that keeps wasps in the garden for the whole season and also spreads brown rot.
• Trying to destroy a nest yourself — Disturbed wasps sting repeatedly and in numbers. It is a job for a professional, and often the nest does not need dealing with at all.
• Assuming the wasps caused the damage — They usually enlarge an existing hole from a bird, a split or a grub. Fixing the first cause does more than anything aimed at the wasps.

Questions people ask