The Leafrollers and the Wasp Enemies

I saw a lot of leafrollers on ornamental plants including wild roses, snow berries, chokecherries, Saskatoons, dogwood, Oregon grapes etc. this spring. As their name implies, leafrollers are caterpillars that roll up leaves. The leaves provide a home, food, and some protection from predators and parasitoids.

The caterpillars are greenish to yellowish, have dark heads and come in different sizes depending on the caterpillar stage and species. The pupae are brownish and covered in silk. Adults are dull-coloured brownish moths. Leafrollers cause damage to leaves and fruit and can be serious pests in tree fruit orchards. Damage to ornamental plants is usually not too serious.

Leafrollers are attacked by predators, parasitoids, and birds. I saw a wasp trying to get a leafroller out of its nest and I waited for the drama to play out. My patience paid off and I was able to get a picture of the wasp taking off with its bounty :). Another wasp was not successful in getting the leafroller caterpillar out of its nest because of an interfering mean yellow jacket wasp. The wasp had worked so hard and was ready to get the caterpillar out when the mean one showed up. The yellow jacket lost interest after a quick look and went on its merry way, which was quite upsetting.

I reared out some moths and small wasps (parasitoids) from leafroller caterpillars I collected in June. The small wasps lay their eggs in the caterpillars in which their young feed and complete development. Good wasps to have around :). Don’t worry, these wasps do not sting people.

If leafrollers are a problem in your garden, you can handpick the leaf rolls if practical to get rid of them. If they are a lot and causing damage, they can be controlled with registered products including Bacillus thuringiensis. Bacillus thuringiensis does not harm good bugs.

It is good to know that the wasp predators and parasitoids are around and doing their bit to help control leafrollers. It was cool to rear out the adult moths and wasp parasitoids and I had so much fun watching the drama between the wasps and the leafrollers. Enjoy the pictures below!

All photos were taken by Susanna Acheampong.