The Newsletter of Pheromone-based Orchard Pest ManagementVol. 1, No. 1 -- March 15, 1996
Areawide IPM Update will:
- Cover pest management topics of interest to those using mating disruption for the control of codling moth (such as pheromone dispenser selection and application)
- Review the monitoring of codling moth and secondary pests
- Present brief updates of ongoing pest management research
In these pages we will discuss current observations of pests and beneficial insects, both within and outside of the Areawide Management sites, and your comments and observations are invited!
Your editor (that's me! Ted Alway) began work in late 1995 as the Extension Program Coordinator for Codling Moth IPM (a title that barely fits on a business card). For the last twelve years I have been the Orchard Production Manager for Wells & Wade Fruit Co./Dole Northwest, and prior to that worked as a pest management consultant in the Yakima area. My position is funded by the Washington Tree Fruit Research Commission and the USDA-Agricultural Research Service, and administered by Washington State University Cooperative Extension. In short, I'll be providing education and information regarding apple pest management in general, and areawide codling moth management/ mating disruption in particular. I'll be editing this newsletter and writing much of it; please call me with your comments, suggestions and articles for Areawide IPM Update. My phone number is (509) 664-5540, fax is 664-5561, and firstname.lastname@example.org is my e-mail address.
Codling moth population level
Probably no factor influences the chance of success more. It is critical to know before the season begins the population level (pressure) you have and, ideally, that of neighboring blocks. Mating disruption (MD) does not work well to reduce high populations down to non-damaging levels. It works best to keep pop-ulations at low levels. High pressure blocks will need to use chemical controls, alone or with MD, to reduce populations to the point where MD can stand alone.
How to measure your codling moth pressure? Dr. Larry Gut suggests three ways:
Mating disruption, used alone, should provide good control and keep populations down in low and very low risk orchards. Moderate risk orchards will need supplemental cover sprays in the first generation to reduce CM pressure to the point where MD can stand alone. The number of sprays needed can be determined in part by the use of pheromone traps (more on this in a later issue of Areawide IPM Update). High risk blocks need insecticides as the main control method. These blocks can be reduced to moderate and low risk levels by combining MD with insecticides. This is an expensive program initially but in many blocks it may provide a long-term benefit by establishing a more stable pest management system. In some blocks, with overhead sprinklers and/or Guthion resistance, it may be the only way to reduce pressure.
Best control with MD is found where physical conditions allow for the uniform distribution and maintenance of adequate pheromone levels within the orchard. For this reason, MD will tend to perform better in flatter blocks. Blocks with steeper slopes may have more difficulty, especially along the top edges.
Orchard size and shape
Orchard borders are at greater risk of CM damage, due to the lower pheromone levels found there and the greater risk of mated females moving into these areas from outside the treated block. Larger blocks and those closer to square in shape are better candidates for MD as their borders represent a smaller percentage of their total area. Long, narrow blocks may be essentially all border and are poor choices, if treated by themselves. There is no fixed minimum size needed for MD success. Blocks as small as two to five acres have achieved good control, when other factors are favorable.
Blocks with very open canopies, due to wide spacings, missing trees or small, young trees, are poorer candidates for MD. These orchards don't retain the pheromone within the canopy well and may, in some areas, have concentrations of pheromone which are too low to be effective. For a similar reason, windy sites may use MD less effectively.
Researchers and extension personnel from the University of California- Berkeley, Oregon State University and Washington State University, together with scientists at the USDA-ARS Research Lab in Yakima, developed a codling moth areawide management plan in 1994. Working with growers in the three states, project developers selected five sites to put this approach into practice and demonstrate its effectiveness and limitations. The sites are:
By early 1995 project managers were hired for each site. Pheromone dispensers were applied by bloom, intensive scouting was begun, and the rest is history (in the making)!
There was a lot to be learned at most sites in 1995. Organizations had to be created, employees hired, data collected and information disseminated. There was a great challenge just in organizing the application of pheromone dispensers, within a narrow time frame, over so many and varied blocks -- 176 in Howard Flat alone! Now, in 1996, with a year's experience under our collective belts, everything should run even more smoothly and we can look forward to a successful and educational season.
The project was organized in early 1995, when Alan Knight and Carrol Calkins from the USDA-ARS Lab in Yakima met with growers and fieldmen from the area. Glenn Richardson was hired as project manager and, with guidance and input from Alan Knight, plunged into the intensive work of mapping blocks, hiring seasonal help, hanging traps, monitoring blocks and more.
In April, Isomate-C+ pheromone dispensers were applied throughout the project orchards and close to 200 codling moth pheromone traps, with 10mg lures, were installed. Reader boards were installed for grower information and updated data was posted twice per week. First cover sprays were applied to all project orchards, and many applied a second cover. For the season, most growers applied 1 to 2 covers, with a few using 3 or 4 in high pressure areas.
Growers at this site are working closely with the Sterile Insect Release Program, located in Osoyoos, British Columbia. This program, begun in 1994, is rearing and sterilizing tens of millions of codling moths annually for release in an effort to eventually eradicate codling moth from Okanagan Valley orchards in British Columbia. The Lake Osoyoos CAMP site was fortunate, through good coordination and cooperation, to have these moths made available to it to aid in codling moth control. Releases of sterilized moths began in late June along pre-determined routes though all blocks. Moths were released twice per week for a total of 600 moths/ acre/week and releases continued until mid-September.
Good codling moth control was achieved in 1995. Fruit cullage from codling moth at harvest was kept below 0.5% in almost all participating blocks, with the main exceptions found next to a large, mostly untreated block in the southwest part of the project. These fruit damage levels are below those found in 1994, when generally 4 to 6 covers were applied in the area, and less than one-third the amount found in nearby, conventionally- treated comparison blocks. Concerns were raised about the ability of the 10mg pheromone traps in the pheromone-treated blocks to accurately indicate the need for supplemental insecticide sprays.
Leafrollers became a concern for most growers in the project in 1995, and fruit injury occurred in all blocks at harvest. Interestingly, leafrollers and their fruit damage were present in much of the Oroville area in 1994 but were not generally recognized. In 1995 no spring leafroller insecticides (Bt's) were applied but many growers responded with summer sprays to limit leafroller damage, using Bt's, Lorsban, or Penncap-M. Monitoring for leafrollers will be stepped-up in 1996, as will examinations of cherry and non-bearing apple blocks in the area, which provided a source of leafrollers in some sites.
No other pests posed any significant problem within the site in 1996. Aphids and leafhoppers generally remained at low levels, and leafhopper parasites were higher in the CAMP site than in surrounding orchards. Leafminer populations were lower within the site and leafminer parasitism was higher, another encouraging sign of potential biological control benefits with reduced use of broad-spectrum insecticides.
In 1996 codling moth sprays in the Lake Osoyoos site may be reduced further while maintaining low levels of codling moth injury. Sterile codling moths from the Osoyoos, BC, facility will be released again, beginning in late June. An early season control program aimed at leafrollers will be needed at all sites, and a more intensive monitoring program will be followed through the season. Secondary pests were not a problem in 1995 and higher natural enemy levels within the site are a good sign of improving biological control.
WSU Cooperative Extension, Chelan County
400 Washington St.
Wenatchee, WA 98801
Partial Funding provided by: Washington State Tree Fruit Research Commission, U.S. Department of Agriculture, International Apple Institute, and U.S. Environmental Protection Agency
Cooperating agencies: Washington State University, U.S. Department of Agriculture, and Chelan County Cooperative Extension programs and employment are available to all without discrimination.