Leaf Rollers

Leaf rollers are green worms that roll themselves in the tips of leaves on trees and vegetables. There are so many different species to mention however they all roll the leaves up and spin a very fine web around this cocoon. 

Red-banded leaf roller (left)-Iowa State University, Fruit tree leaf roller (right)-University of Californis

Description 
Tree leaf rollers are one and I’ll classify the other as vegetable/plant attackers. Because there are so many different types, they are named by what they attack.

Female Adult (left)-HYPP Zoology, Pupae (right)

Habitat
They are found throughout North America and are mostly active in the early summer months. As soon as the ground warms up the eggs hatch, these guys waste no time finding a great plant to eat. In the case of trees, the worms climb up the trucks or branches to the nearest leaves to feed.

Leaf Roller Lifecycle (left)-INBAR, Egg Mass on Bark (right)-HYPP Zoology

Lifecycle
Plant leaf rollers overwinter as eggs in the ground in garden debris and fallen leaves. The caterpillar emerges in the spring and attacts the nearest tasty host plant. Mostly these are fruit trees but they do attack all sorts of other garden crops and plants. Tree leaf rollers overwinter as eggs attached to trunks and twigs of host plants. In June or July the caterpillars become moths that will lay eggs and begin the cycle again.

Leafroller Damage (left)-University of Maryland, Tea Leafroller (right)-UPASI Tea Research Foundation

Diet and Damage
The leaf roller type that attact trees can be devestating! In large numbers they skeletonize leaves and enfold fruit between their webs. They can even eat holes in small apples and other fruit. Vegetable leaf rollers are much easier to control as it is easy to see a leaf in the process of rolling.

Control
1) Bt
Leafrollers can be controlled with a spray mix Bt. It must be applied while the worms are small and before they spin a web as the webbing will protect them from this.
2) Hand Pick
Remove any leaves that are rolled and with webbing and burn. On trees you can clip whole branches off. It is also easy to crush them after removing affected leaves.
3) Predatory Insects
Praying mantids, birds and trichogramma wasps are predators of these guys but again only before webbing occurs.
4) Dormant Oil Spray
Spray trees in the fall and again in the spring to ensure smothering the overwintering eggs.
5) Soap Spray
Use a soap spray directly on the caterpillars before they can complete a ‘coccoon’