Natural Prevention of Leaf Roller Worms on a Saskatoon Bush

Description and Damage

• Leafrollers are the larval stage of various species of adult moths that lay their eggs on smooth surfaces such as the leaves of a Saskatoon bush. These 1/2- to 1-inch-long worms roll leaves up with a silk-like material, creating a protective hiding place. Leafrollers feed on tender leaves, causing the edges to appear ragged or creating jagged holes in the foliage. On fruit-bearing plants, leafrollers will also feed on fruit.

Biological Prevention and Control

• Introducing beneficial insects that prey on leafrollers helps control their numbers and prevents a caterpillar infestation from occurring. Tachinid flies, braconid wasps, assassin bugs and lacewings attack leafrollers. These beneficial insects act as a natural preventative to various species of leaf-eating caterpillars. Planting fragrant annual herbs -- such as dill (Anethum graveolens) and basil (Ocimum basilicum) -- helps to entice these desirable insects to your garden. Beneficial insects alone typically cannot properly manage a severe leafroller infestation and work better as a preventive measure.

Cultural Prevention and Control

• The University of California Statewide Integrated Pest Management Program suggests keeping your garden clean and free of debris, trash and weeds as a possible solution for leafrollers. In addition, manually remove webbed leaves and leafroller worms from the Saskatoon bush. Even though leafrollers are not typically harmful to humans, you should always wear work gloves before manually removing them to protect your skin from possible irritation. Once removed, dispose of the worms in a bucket filled with hot soapy water.

Organic Insecticides

• The microbial insecticide Bacillus thuringiensis can safely control leafrollers without posing a hazard to humans, pets, mammals, fish or beneficial insects. This naturally occurring soil bacterium acts as a poison that causes the leafrollers to starve a few days after they consume it. Four teaspoons of concentrated Bacillus thuringiensis mixed with 1 gallon of water and sprayed on the underside and topside of the Saskatoon bush leaves will control leafrollers without toxic chemicals. However, since the application instructions vary depending on the brand and type of microbial insecticide used, make sure to follow the directions on the label for best results.