Wasps on fruit, how to prevent, deter or kill this problem.

“Anger is as a stone cast into a wasp’s nest”.
Chinese Proverb.

It feels like this year is fast becoming the year of the wasp. Despite all the wet weather we have received there has been plenty of wasps around. You would expect the dampness would put them off, but no, they seem as plentiful as they are in a warm summer, if not more so.



Now I’m all for insect life in the garden but the wasp skirts dangerously close to warranting an entry in my bad books. First off, for the general garden user you have the slim possibility of going into anaphylactic shock when stung by a wasp. This allergic reaction thankfully only affects three percent of the population, but when it does it results in swelling of the face, lips throat, or eyes combined with difficulty breathing.

Wasp feeding on fruit, photo / pic / image.

Wasp feeding on fruit, photo / pic / image.

Fruit growers .
Another percentage of garden users badly affected by wasps are the fruit growers. Especially those of you growing soft skinned fruits such as plums gages, or grapes, but even apple and pear growers can be affected. These fruits can take a beating when summer turns to autumn causing wasps to alter their feeding habits from mainly carnivorous to mainly vegetarian.

In early summer our common wasp (Vespula vulgaris) seek out and capture other insects, chew them to bits, then feed their young larvae the shredded mix. The larvae are maggot-like and wingless, so they require a steady supply of chewed insect.


This insect capturing prevents me from totally hating wasps, as they can be a beneficial predator accounting for a good reduction in greenfly, caterpillars and other pests that attack our plants. However, it’s in autumn when brood rearing has ceased in their nests that the adult wasps turn their attention to sweet things, with soft skinned fruits greatly attracting these “sugar eaters”.

Wasp damage on fruit can be quite disheartening after all your time spent waiting for it to form. The wasps burrow into the fruit, hollowing them out as they feast on the sugary flesh. It can be really shocking to pull a plum from one of your trees and just before you bite into it you spin it round to discover a tangle of wasps within a cavity.

A tried and trusted solution to this problem is to hang a fake wasps nest from one of your fruit trees. When wasps visiting your garden see another wasps nest they will quickly leave the area for fear of being attacked by the nest’s inhabitants. The waspinator mimicks a real wasp’s nest, is weatherproof, and can be squashed flat for transport.

Now although wasps have the ability to pierce the skin of your fruits and initiate feeding, it is more common for them take advantage of a pre-existing break in the skin. They then expand upon this allowing them access to the succulent flesh.

Breaks in the skin or splits are common when a deluge of rain follows a dry spell of weather. This excess moisture causes the fruit to swell quickly and skin to split.

If you wish to avoid splitting you should dig in plenty of well-rotted organic matter when planting your tree and apply a layer of similar matter beneath its branches each spring. During a prolonged spell without rain (week or more) you should water gently but deeply once a week. As a rough rule of thumb apply approx 10 litres per metre squared of soil area.

Even without fruit splitting you may still suffer from wasp damage to your fruit, so what can you do? Well many gardeners recommend going straight to heart of the problem by destroying the wasps nest or nests in your garden, if you can find it.

Nest destruction can be carried out through applying a powder containing the active ingredient Bendiocarb at dusk when the wasps have all returned for the night. This should be shook over the nest and in mounds covering the entrance. Wasp Nest Killer is the product commonly used for this procedure. Ebay is a great source for this.

Be careful of disturbing the nest if you attempt this treatment as wasps are very territorial. As an old Chinese Proverb states… “Anger is as a stone cast into a wasp’s nest”.

Besides nest destruction here are a three other ways to prevent wasp attack to your fruits….

(1) Be tidy.
Pick up any windfalls or damaged fruit, as they will attract wasps if left on the ground.

(2) Wasp traps.
Finished with jam, marmalade or honey jars? Turn them into a wasp traps by leaving a bit of the sweet spread in the base, filling half way with water, then with the caps on shaking them vigorously. Next pierce a hole in each lid to allow wasps to enter before you finally position them to intercept wasps on their way to your trees.

(3) Bagging.
Although time consuming, most forms of “on the tree” fruit bagging are effective in preventing wasps getting access. Some gardeners will opt to use clear plastic bags and others use old pairs of tights for the purpose. Whatever is used it should allow fair light transference to facilitate fruit ripening.

Solutions from times past and home remedies.
I dug a little deeper trawling through old gardening instructional manuals and I came up with this gem…… “THE BOOK OF PEARS AND PLUMS” by , Reverend Edward Bartrum , 1833-1905. Much of the core info in it stands up even today but some of the phrasing and methods in it are too funny. I’ll leave you with the wasp text from it, enjoy reading, but exercise caution with many of the processes mentioned

Their nests often hold many thousands. Large numbers may be destroyed thus : place a hand-light upon bricks, make a small hole in the top of this, and over it put a sound and closely-fitting one. Fruit cut open should be thrown beneath the lower light. The wasps often go up through the hole, and do not return. Their buzzing attracts others. Destroy by burning sulphur beneath, or by drowning.

A glass destroyer on a similar principle is sold in china-shops. Open-mouthed bottles filled with beer sweetened or water sweetened with treacle will lure many to destruction.

Queen wasps in spring and wasp- nests must be noticed and destroyed. Fasten a piece of cloth soaked in a solution of cyanide of potassium (a small quantity dissolved in hot water), and put it in the nest; all the wasps will be killed. Dig out the grubs. This is a deadly poison, and should be handled only by an expert. The emanation from the solution must not be breathed. Tar does almost as well.

A nest may be partly dug and flooded at night. A clean wine bottle (half-filled with water) inserted in the place of the nest (the top of the neck level with the surface of the ground) will probably capture all stragglers.

Some make a heap of injured fruit and syringe the wasps with nicotine soap, eight ounces to a gallon of hot or cold water. This plan kills quickly, but the fruit no longer attracts.

Squibs a half-inch in diameter, three inches long, made of gunpowder moistened with water, one-fourth of flowers of sulphur added, mixed into a paste, wrapped in brown paper, and tied at one end, are good for the work. After dark, light the squib, push the lighted end into the hole, put a sod over, and ram it in to confine the fumes. In a few minutes dig up and destroy the grubs, then fill up the hole. If the nest is high up, attach the squib to a stick, light, and keep it close (while burning) to the entrance. Young gardeners enjoy this squibbing process. :shock:

More debate about this topic on our forum, click Irish gardeners forum.

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