Good Fruit Grower

October 2012

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Apples Insect-resistant varieties S Resistant apple varieties could reduce the need for insecticides. by Geraldine Warner cientists at Washington State Uni- versity hope to breed apples with resistance to key apple pests. Joseph Schwarz, a doctoral stu- dent with WSU in Wenatchee, this summer reported progress in identifying apple cultivars that seem less appealing than the standard varieties to codling moth and obliquebanded leafroller. Genetically resistant varieties could reduce the need for insecticide applica- tions and, in turn, reduce problems with disruption of secondary pests or develop- ment of pest resistance to insecticides. They could also help enhance biological control and reduce concerns about insecticide residues on fruit. Schwarz is conducting his research in a genetically diverse block of apples at WSU's Sunrise research orchard near Wenatchee. Established as a resource for the breeding program, the block includes 236 different accessions from the National Clonal Germplasm Repository in Geneva, New York. It contains apples from wild forests of Kazakhstan and China, heir- loom varieties, and material representing popular cultivars of the world. Schwarz is focusing first of all on screening the trees for natural resistance Joseph Schwarz explains how he screens trees for resistance to leafrollers during WSU's field day. Schwarz is looking at when the larvae to leafrollers and codling moth. He then hopes to identify the genes that are asso- ciated with the resistance. Eventually, genetic markers would be developed to identify resistance in potential parents used in the breeding program and to screen their progeny. During WSU's summer field day at the Sunrise Orchard, Schwarz described how he has been taking leaf samples from trees and putting them in feeding chambers in the laboratory with newly hatched leaf - roller larvae. Leaves of Granny Smith and Gala apples are used as controls. Larvae development is monitored weekly. COLD AIR DRAIN Frost Protection ® pupate, how much they weigh, and when they emerge as adults. He is also studying the fecundity and mortality of the adults. He began the work last fall and will con- tinue for another couple of years. Schwarz said some varieties look promising, but the tests will have to be repeated so that seasonal variability can be accounted for. He expects to start next year with experi- ments with codling moth, exposing them to whole fruit from the various trees in the block. Dr. Jay Brunner, director of the Tree Fruit Research and Extension Center, who is Schwarz's advisor, said even if a variety has less than 100 percent resistance to the pests, it could still be useful. "If we can get a slowing of the development of the leafrollers, that allows more opportunity for biological control. If the insects are nutritionally challenged, or affected by some of the genes and are not as large, they will lay fewer eggs." Schwarz earned his bachelor's degree in biology at Kean University in New Jersey and a master's degree in chemical ecology from Simon Fraser University in British Columbia, Canada. He is pursuing a doctorate in entomology. • CO T E COST EFFEC CTTIVE! Most system Minima ma POWERFUL! VERSATILE! ATIL No maintenance contracts. StatState-o theoff-the-art pro Size & power mal site prep. Fuel efficient. ance mss have a 100% re Fu Targeted protection for frost pockets, swales, slopes, valleys, etc. Use alone or with wind machines, water, or heaters. r o options avai ab r fr ailable to mee cke meet your needs. wal FREE COMPUTERIZED FROST ANALYSIS & PRICE QUOTE! SHuR FARMS® Frost Protection 1890 N. 8th Street, Colton, CA 92324 877.842.9688 or 909.825.2035 32 OCTOBER 2012 GOOD FRUIT GROWER c. 100% payback rac ropeller sends co ack i in the firs cold air rst year r u up ap ar. approximately 300 ft. Photo by Geraldine Warner

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