Washington State University Cooperative Extension

Areawide IPM Update

The Newsletter of Pheromone-based Orchard Pest Management

Vol. 1, No. 1 -- March 15, 1996



About This Newsletter

Areawide IPM Update is a newsletter for participants and cooperators in the Codling Moth Areawide Management Projects, made possible with funds provided by the International Apple Institute, in partnership with the Environmental Protection Agency. Areawide IPM Update will be distributed once or twice per month, beginning in mid-March and continuing through the end of the growing season. The newsletter will also be available electronically, both on the electronic bulletin board of the WSU-Tree Fruit Research and Extension Center in Wenatchee, and at www.tfrec.wsu.edu on the Internet.

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 alway@coopext.cahe.wsu.edu is my e-mail address.


SELECTING SITES FOR MATING DISRUPTION

The potential for successful control of codling moth (CM) is not the same for all orchard blocks. Consider several factors before you place pheromone dispensers in your trees.

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:

Fruit injury counts for codling moth from packout records or field counts provide the best measure. Field counts can identify hot spots that may need extra treatment the next season.
Pheromone traps can give a good indication of codling moth pressure, if traps are maintained correctly and used at an adequate density.
The number of insecticide applications needed for CM control can give an indication, if based on some measure of the need for control (e.g. fruit injury or trap catch).
Using these criteria, Dr. Gut has proposed to group Washington orchards into four risk categories:

Very low risk: fruit damage from CM the previous year less than 0.1%. These blocks will typically require 0-1 sprays for CM control in the season ahead.
Low risk: CM fruit damage of 0.1-0.4%. Generally 1-2 sprays will be needed for CM control.
Moderate risk: CM fruit injury of 0.5-1.0%. Typically would require more than 2 covers for adequate control in the season ahead.
High risk: CM fruit injury of 2.0% or more. A full season control program, involving 3-5 treatments or more, will be needed for adequate control.
In assessing CM risk, always be aware that CM populations generally are not uniform, and borders andhot spots can need additional controls. Orchards where codling moth show Guthion resistance may require more sprays to achieve control.

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.

Orchard topography

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.

Orchard canopy

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.


Areawide Management of Codling Moth: Program History and Overview

The Codling Moth Areawide Management Program (CAMP) began in 1993 when university and USDA scientists selected codling moth as the prime target for an areawide pest management program. Codling moth is the "key" pest for most Western apple and pear growers. It is found in all growing areas and without control it will cause very serious crop loss annually. The insecticides used for codling moth control often can interfere with the biological control of other orchard pests, such as leafminers and pear psylla. In addition, codling moth resistance to Guthion, the main insecticide used for control, is becoming more widespread. The USDA was interested in promoting and funding an "areawide" approach, treating a large and contiguous acreage of orchard using a non-disruptive approach like mating disruption. The hope was that this would permit, over time, equal or better control of codling moth than conventional approaches, reduce the need for treatments of other pests, and reduce broad-spectrum insecticide use by 80%.

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:

Each site will be profiled in upcoming issues of Areawide IPM Update.

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.


CAMP Site Profile: LAKE OSOYOOS

The Lake Osoyoos CAMP site consists of 378 acres of orchards on either side of Lake Osoyoos near Oroville, WA, and adjacent to the Canadian border. Thirteen growers participated in the project in 1995, which involved some 65 distinct blocks. Apples make up over 90% of this acreage. Reds and Goldens predominate (62% of acreage), and there are significant amounts of Fuji, Gala and Granny Smith apples, and small amounts of pears and stone fruits. This site is well separated from other orchards to the south by large areas of unplanted, rocky hillside.

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.


AREAWIDE IPM UPDATE
Ted Alway, Editor
Phone: (509) 664-5540
Fax: (509) 664-5561
e-mail: alway@coopext.cahe.wsu.edu

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.


Wenatchee WA, 15 March 1996
webmaster@tfrec.wsu.edu