What the heck is a pear slug?? These are not your typical, large ground sliding, slimy slugs. These are tiny and are also known as cherry slugs. In Latin they are known as Caliroa cerasi.
Cherry Slugs aka Pear Slugs have a maximum size of ½” whereas the normal ground dwelling garden slugs that are usually around 4″ long but can reach up to 8″ long.
Despite their name, Pear Slugs are actually an insect. They are the larva of the Sawfly.
These little guys are tiny but very destructive. Pear slugs prefer your pear trees and cherry trees but will also eat other similar varieties too if they are available.
Among the most commonly affected are the Plum, Hawthorn, Apricot and Cotoneaster, as well as Apple and Quince.
It’s important to take eradication action as soon as you see the problem. They have two hatching cycles per season and can be very detrimental to a tree.
They will eat the leaves of the current years growth but will also over-winter in the bark and soil around the tree and be back in force next year after the winter has passed to complete their life cycle, and begin eating the leaves all over again in greater numbers.
The second generation is more destructive and active than the first. If you live in a warm temperate climate you may face 3 generations per season.
Pear Slug Damage
At first your leaves will appear spotty and brown, then very quickly will turn papery and crisp. Then they will eventually shrivel and fall prematurely.
If the infestation is really severe you will actually be able to hear the slugs eating the tree.
If you see them on your tree the only thing that you really need to know is how to get rid of them right away.
The quickest and very effective remedy to this pest is to use a solution of dish soap and water in a spray bottle or hose end sprayer if it’s a large tree. The goal is to completely saturate your tree with the solution.
It’s important to completely, 100% saturate your tree. The pear slugs are very sensitive to dish detergent but will only die if the dish soap comes in direct contact with them. They will dry out, shrivel up and die promptly. The dish soap cuts through their outer protective layers of slime and they quickly dehydrate.
If your tree is small then a squirt bottle or small air pressure sprayer is fine but if your tree is large then a hose-end sprayer or backpack sprayer will be required.
Remember that complete saturation is required. Over-spray and dripping onto the soil is fine, it will allow the excess dripping of the solution to come into contact with the ground dwelling larva waiting for their turn which are invisible to us.
Keeping the ground area under the tree clean is a big part of the remedy as well. If you have thick plants such as ivy surrounding the base of the tree, I recommend removing this as this is perfect sheltered breeding ground for them.
The pear slugs are protected from the elements and are over-wintering in there to breed again in the spring.
The ivy is helping to make the problem much worse and will make it more difficult to combat the problem.