How can I control pear psylla organically?
Answer: The pear psylla (Cacopsylla pyricola), an aphid-like insect whose only host is the pear, is the crop’s most significant insect pest. In conjunction with fire blight, pear psylla is largely responsible for declining eastern pear production. The honeydew left by the psylla damages the fruit by supporting growth of sooty mold and causing a black russeting; these two effects account for most of the economic damage caused by the psylla. It is also an important vector of fire blight and pear decline disease and can weaken trees in areas of heavy infection.
Although the psylla develops resistance to insecticides, it can usually be controlled either with dormant oil sprays or with sulfur sprays (but not a combination of the two, which damages plants). Insecticidal soap can reduce active populations during the growing season. Fortunately, the recently introduced Surround™ kaolin-clay-based insect repellant is effective against pear psylla. In fact, use of Surround for pear psylla control has made organic pear production viable for the first time in states like Michigan. The psylla also has a number of natural enemies such as predatory flies, minute pirate bugs, and lacewing larvae. In organic orchards. Parasites and predators can help control psylla below economically damaging levels, especially when combined with a program of oil treatments.
Ready to learn more? Check out the ATTRA publication Pears: Organic Production, which addresses pear diseases, disease-resistant cultivars, rootstocks, insect and mite pests and their treatment, Asian pears, and marketing. Two profiles of organic pear growers are included.
In addition, you’ll benefit from the ATTRA Identification Sheet: Pear Insect Pests, which serves as a handy visual guide for identifying insects that affect pear production and learning about control options.
Note: the mention of specific brand-name products is for educational purposes only and does not constitute endorsement by NCAT, ATTRA, or USDA.