Inside of the leafroller nest. The leafroller had already started to pupate and form a cocoon
Thaddeus McCamant, Central Lakes College
Leafrollers are caterpillars that feed on the young leaves of many different species of shrubs and trees, including apples and blueberries. The young caterpillars use silk to tie two or three leaves together, typically at the tips of the branches . In addition to feeding on leaves, leafrollers will eat green or ripe fruit near leaves with webbing. There are at least three species of leafrollers that feed on blueberry leaves in Minnesota, including the obliquebanded leafroller (Choristoneura rosaceana), the red-banded leafroller (Argyrotaenia vultinana) and the blueberry leafroller (Sparganothis sulfureana).
Leafroller moths lay egg masses on the leaves. Shortly after hatching, the caterpillars start attaching several leaves together. Older caterpillars often leave their nest to feed on other leaves or young fruit, but when they are ready to pupate, they form cocoons in the leaves. Most leafrollers have two generations per years in Minnesota.
Leafrollers usually only damage a small percentage of the leaves on a blueberry plant, and management is rarely necessary. Leafroller populations are usually kept fairly low by natural predators and parasites.