1a. Objectives (from AD-416)
Evaluate the components of the systems approach for sweet cherry, including (1) the use of larval distribution data, (2) chemical controls, and (3) fruit inspection.
1b. Approach (from AD-416)
The infestation patterns of western cherry fruit fly larvae within orchards will be determined bt sampling fruit and rearing larvae out. Effects of insecticides on larval infestations will be determined by applying insecticides at specified intervals and collecting fruit and examining them for larvae. Brown sugar and hot water detection methods for larvae will be compared by determining the numbers of larvae collected versus total numbers present, and improved if needed by altering the crusinging mechanisms.
3. Progress Report
This project is an extension of research on the management of insect pests of temperate tree fruits and addresses objective 5 of the related in-house project. This project relates to NP 304 4B because it addresses control of insect pests of tree fruit to meet strict consumer standards while reducing pesticide use. In 2010, brown sugar flotation and two hot water methods were evaluated for their effectiveness in detecting larvae of western cherry fruit fly from crushed cherries. The methods are used to document the absence of larval infestations at cherry packinghouses. Cherries were crushed and brown sugar solution or hot water was poured over cherries. The solutions were inspected for larvae that were liberated from the fruit. Crushed cherries were preserved in alcohol so that they could be examined under a microscope for larvae that were missed during the initial inspections. The cherries were examined for larvae throughout fall, winter, and spring 2011. Percentages of larvae that were detected were calculated using numbers of larvae initially recovered plus those found in cherries through examinations under the microscope. It was found that the brown sugar method was more effective at detecting larvae than the hot water methods. In July 2011, a similar test comparing brown sugar flotation and salt flotation methods is being conducted. In 2010, flies were released into two experimental orchards that had very low infestations to determine the spread of the fly based on distributions of larvae in fruit from different sections of the orchard. Flies seemed to attack the cherries uniformly in these orchards, such that cherries farthest from the release points were as infested as cherries near release points, implying that flies dispersed quickly through the orchard. The distributions of larval infestations in two experimental orchards are being determined in July 2011. In 2010, studies were conducted on effects of pre- and post-harvest insecticide treatments on larval infestations. Cherry trees at the USDA experimental research farm were sprayed with sugar baits containing the insecticide Actara and with the protein-sugar bait GF-120 over the 5-week season and infestations in the cherries evaluated. Actara reduced infestations significantly more than GF-120. At post-harvest, the most effective material was dimethoate. In 2011, a continuation of the 2010 tests is being conducted. In addition, the residual activities of Actara and GF-120 are being studied. Data collecting for this test is being conducted and will be completed by August 2011. Monitoring of activities and progress on this project was accomplished by direct supervision of on-site employees, and use of site visits, email and telephone to communicate with off-site collaborators.