Thousands of varieties of apples grow worldwide but only a hundred or so are commercially grown. Apple varieties are available to suit every local climate condition, including heritage varieties such as “Augustus Start,” “Paradise Sweet” and “Old Timey Pippin.” Several types of moths and insects infest apple trees, causing disfiguration and disease. Organic growers use methods of integrated pest management to eradicate these insects.
“Organic growing methods utilize only naturally occurring substances or organisms for fertility management and pest and disease control,” according to the National Sustainable Agricultural Information Service report on apple growing. The major focus of difference between conventional apple tree care and organic care is the use of nature-based pest control rather than chemical-based pesticides.
Organic pest control in home gardens and large organic farms often begins with a pest-by-pest plan for controlling harmful insects. This approach gradually evolved in sustainable agriculture to the methods and theories of integrated pest management (IPM). The University of California at Davis uses a computer-based “pest cast” forecasting system to help organic farmers anticipate disease problems with the goal of reducing unnecessary pesticide use. Insect biological patterns are determined by heat and cold, making pest “weather reports” a practical prediction method.
The coddling moth is the most common apple tree insect pest. One of the most promising organic deterrents for this insect is the use of naturally produced pheromones to disrupt its mating phase. Pheromones are released through a dispenser placed in the orchard. Pheromone traps are available through agriculture supply companies. Growers in California have improved codling moth control by combining mating disruption with black light traps, which are available commercially. The trichogramma wasp eats coddling moth eggs and is also used as a biological control.
Beneficial insects such as the trichogramma wasp are attracted to apple tree growing areas by flowering plants with nectar. In the home garden, plants such as spearmint, Queen Anne’s lace, yarrow, white clover, tansy and cosmos attract beneficial insects that in turn protect the apple trees. Large-scale organic apple growers often grow beneficial wildflowers and cover crops between tree rows. This kind of integrated planning is known as farmscaping.
Kaolin clay is marketed under the name Surround and has been shown to be effective in controlling all apple tree pests with the exception of the wooly apple aphid. It is the same edible mineral compound used in toothpaste and Kaopectate. Surround is sprayed on as a liquid that dries and leaves a film on all parts of the tree and fruit. Minute particles of clay attach to insect bodies and the agitation causes them to leave the tree.