The second generation of larvae are usually most active in September. The pear and cherry slug eats the leaves of pears, cherries, apples, plums, quinces and hawthorns. In these situations pear slugs may need control. Pam Peirce's classic regional book, "Golden Gate Gardening," has been helping California gardeners grow food since 1993. Q: Is it normal for radish roots to stick up partway out of the ground? Check under potato plants and cover any visible tubers with soil or mulch. Apply to CSU | • Pear slugs are not true slugs. If a problem develops, it is usually after harvest on cherries when insecticides are no longer being used. In Canada its preferred hosts are cotoneaster, hawthorn, mountain-ash, pin cherry, and various other fruit trees. • Two generations of pear slug occur. However, serious infestations can damage most of the leaves and cause them to fall. For light infestations, remove the infested leaves and destroy the larvae. The damge from this generation is usually more severe, sometimes retarding tree growth the following year. Inspect both upper and lower surfaces of the leaves. Most plants can tolerate 25 percent to 30 percent leaf loss, so light infestations aren't a serious threat. When heavily damaged, the entire leaf falls prematurely. Pear sawfly prefers pear and cherry hosts but will also attack the leaves of plum, quince and occasionally apple. We have 3 regions; Peaks and Plains, Front Range and Western. You don't have to cover up the exposed part of the root. Newly molted larvae are yellow until the slime is secreted. A pear slug is the larval stage of a kind of sawfly, Caleroa cerasi. Attacks pear, cherry, and plum. Pear and cherry slugs are leaf damaging larvae of a sawfly. CSU Extension - A division of the Office of Engagement. Management Notes Its third edition, released in spring of 2010, includes much new material, including new planting calendars that carry its usefulness much farther inland than previous editions. These larvae feed and cause damage on many kinds of ornamentals and fruit trees, including cherry, cotoneaster, mountainash, pear, purple leaf - As feeding progresses, the affected areas on individual leaves enlarge and merge, until the leaves look bleached. Thresholds On heavily infested trees, the leaves will turn brown, wither and drop. Pear sawfly prefers pears and cherries but will also damage leaves of plum, quince, and occasionally apple. Hosts include American mountain-ash, cherries / plums, common pear, hawthorns, plum, quince, serviceberries. The adult female inserts eggs into the leaf tissue with her saw-like ovipositor. Both are permitted to organic farmers. The larva passes through five instars. Pear sawfly feeds on the upper surface of leaves, skeletonizing them. Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status. They tend are a type of insect known as sawflies. Equal Opportunity | Re-inspect in late July or August for the summer generation. Jeffrey W. Dwyer, Director, MSU Extension, East Lansing, MI 48824. There is usually only one generation per year, but in suitable weather a smaller second generation may complete development before winter arrives. A pearslug, shown here on a plum leaf, is a caterpillar that eats all of leaves but the veins. The first signs of damage are little yellow spots on the leaves of the tree from young larvae feeding. It is occasionally found on quince and shadbush. Pam Peirce is the author of "Golden Gate Gardening" and "Wildly Successful Plants: Northern California." (You might prefer to wear gloves, though.) They lay eggs in slits made in the leaf. If feeding is extensive, leaves may brown and shrivel. Pear sawfly overwinters as a pupa in a cocoon 2 to 3 inches deep in the soil. The larva is small, fleshy, dark green to orange, slug-like, and slime-covered, with the front part of the body enlarged (A). They avoid the larger leaf veins and rarely penetrate the lower leaf surface. Scouting Notes Eventually, mature larvae feed on the surface of the leaves and skeletonise them by removing all leaf tissue except the fine network of veins. Larvae feed on the surface of leaves, which they skeletonize, leaving only a framework of veins (C). Pear slugs (often called “cherry slugs”) feed on the leaves of certain commonly planted trees and shrubs during mid- to late summer. The eggs hatch 9-15 days later and the larvae begin feeding on the upper surface of leaves. It gives them that bold, come-hither look that makes me want to pull one up and eat it on the spot. Pam also helped to found the San Francisco League of Urban Gardeners, or SLUG, an organization to support community and home gardeners, and served on its board from 1983 to 1999. WA 38 First Commercial Season Storage & Packing Observations, WA 38 Optimization of Light Interception…, Pear Psylla Management using Reflective Plastic Mulch, Pear Psylla Insecticide Bioassay – Egg Mortality, Pear Psylla Management – Postharvest Sprays, Pear Psylla – Summer Generations Overview and Management, Management of Little Cherry & X-disease for Backyard Producers.