Washington State University Cooperative Extension

Areawide IPM Update

The Newsletter of Pheromone-based Orchard Pest Management

Vol. 3, No. 1   January 1, 1998

Inside this issue:

Web links:

...Ted Alway's Areawide IPM page

...USDA Yakima Areawide IPM page (with CAMP site descriptions)

...WSU-TFREC Entomology home page

...Index to Areawide IPM Update newsletters

Cooperating agencies: Washington State University, Oregon State University, University of California, U.S. Department of Agriculture, and Chelan County.

Cooperative Extension programs and employment are available to all without discrimination.

  

1997 - CAMP Year in Review

1997 marked the third year of the Codling Moth Areawide Management Program (CAMP) and by most measures was a success. In general, codling moth populations and fruit damage were down, and many growers were able to reduce inputs of insecticide sprays and pheromone dispenser rates. The five sites established in 1995 (Randall Island, CA; Medford, OR; West Parker Heights, WA; Howard Flat, WA; Lake Osoyoos, WA) completed their third year using mating disruption for codling moth as the key part of their areawide control program. These sites have received funding from the USDA-Agricultural Research Service for monitoring and coordination, and a subsidy of 50% of the cost of pheromone dispensers; the latter subsidy will not be available in 1998 and 1999, the two remaining years of the program.

In addition, five new sites were established in 1997. Each of these received USDA-ARS monetary support for monitoring and coordination only. These 1997 sites are Ukiah, CA; West Wapato, WA; Manson, WA; Brewster, WA; and Progressive Flat (Okanogan), WA. The developments at each of these five sites will be reviewed in the next newsletter.

The original five camp sites

Randall Island: The Randall Island Project (RIP) is the "granddaddy" of the CAMP sites, having just completed its fifth year using mating disruption (MD) for codling moth control. The areawide control approach in this area of Bartlett pear orchards in the Sacramento River Delta has been successful, with codling moth damage averaging below 0.4% and organophosphate insecticide use reduced 72%. The approach has also undergone substantial change since its beginning in 1993.

In 1997, only a single application of Isomate C+ was used, in contrast to the double applications made in previous years. The two-application approach is uneconomical for growers; if MD is to be used cost-effectively in California a single application must be adequate. This year the pheromone dispensers were applied close to April 1, soon after biofix (first male flight). Under this areaˆs conditions, the Isomate C+ dispensers have been found to release pheromone until early September, after pear harvest is complete. A single application of an organophosphate (Guthion or Penncap) was made to most blocks at the "B" (second) peak of the first generation codling moth flight, approxi-mately 700 degree-days after biofix. This simple program has been enough to keep both codling moth and leafroller damage to fruit at low levels, equal to standard programs relying upon four OP applications.

Studies of codling moth resistance to OPˆs continues at RIP. A "mosaic" has been used, where blocks within the site received either one application of Guthion, one of Penncap, or none at all. Dr. Steve Welter of UC-Berkeley, the projectˆs coordinator, has found that conventional blocks in the area have codling moths with a Guthion LC50 of ca. 0.5 µg/L. The Penncap-treated areas in RIP in 1997 had moths with an LC50 of 0.21 µg/L; in an organic block where no Guthion has been used for many years, it was a low 0.08 µg/L. These studies indicate that not only can Guthion resistance be reversed, it can also be done on fairly small acreages.

Codling moth MD use in California has increased slowly, being limited mostly to pear producers. The original use of a two-tie program with pheromone dispensers was cost- prohibitive and scared off many growers. However, several PCAs (pest control advisors) are working with MD in their pear pest management programs, including the use of reduced dispenser rates. MD is used little by California apple growers at this point, many of whom are faced with even higher codling moth populations and, in the San Joaquin Valley at least, very hot summer temperatures that further shorten the life of pheromone dispensers. Apple growers in cooler districts may find more benefit from including MD in a control program. Increasing resistance to pesticides (by both codling moth and consumers) and the implementation of the Food Quality Protection Act may also spur some increased adoption of MD.

Medford: This CAMP site, located southwest of Medford, was expanded in 1997 to close to 500 acres, involving 6 growers. It now includes nearly 400 acres of pears (12 cultivars, Bosc and Comice being the most common) and about 100 acres of apples (Granny Smith, Braeburn, Gala and Fuji). There were also close to 800 acres of MD outside of CAMP in the Medford area in 1997.

MD for codling moth has been used within the CAMP site as part of a selective pest control program developed here at the Southern Oregon Research and Extension Center. This program seeks to minimize the adverse effects of synthetic pesticides, improve biological control of pests, and maintain acceptable crop quality and productivity. A key part of their program on pears has been the application of horticultural spray oil at ca. 200, 400 and 600 degree-days (ƒD ) after biofix for control of codling moth, pear psylla and spider mites. Isomate C+ pheromone dispensers for CM have been applied at 400 per acre, and almost all of the acreage received one late-season OP (Guthion or Imidan) for supplemental control at close to 1250 ƒD.

Fruit damage at harvest from codling moth and leafrollers has declined since 1995, the programˆs first year; in 1997, codling moth damage averaged 0.09% and leafrollers 0.23%. However, damage from true bugs, including lygus, box elder and stink bugs, doubled from the year before to 1.8%, accounting for over three-fourths of all damage. This follows an increase in bug damage in 1996, as well. Although fruit damage from bugs increased in the conventional comparison blocks, indicating the problem is widespread, bug damage does appear to be higher within the CAMP blocks on some cultivars. Efforts will be increased in 1998 to better detect the sources and presence of true bugs, apply protective sprays as needed, and investigate managing the cover crop and surrounding vegetation to reduce the risk of bug damage.

Overall, the Medford CAMP site has seen synthetic pesticide use reduced by 80% when compared with conventional blocks in the area. Much of this reduction has been in the often expensive psyllicides and miticides. This reduction is attributed to the pest control benefits from the horticultural oil sprays, and improved biological control from the elimination of early season OPs. Control costs have also been reduced, while pest damage is more or less equivalent to conventional blocks. The growers here express concerns with the need to develop better means of monitoring leafrollers, true bugs and natural enemies, and with the difficulty of predicting codling moth damage from pheromone trap catches, i.e., false negatives, where damage is found despite low or no catch in traps in that area. This project will continue in 1998 with the same acreage expected to be in the program.

West Parker Heights: This 500-acre site in the Yakima Valley just completed its third year in the areawide control program with codling moth populations and fruit damage at their lowest levels ever. The seven growers at this site switched in 1997 to using Isomate C+ dispensers almost exclusively, leaving but 11 acres of Checkmate CM. Isomate was used at 400 per acre by all growers. Several blocks were treated with Isomate C Super, a "dual" dispenser containing both codling moth and leafroller pheromones.

Codling moth populations here, as determined by seasonal catch in pheromone traps, declined slightly from 1996 levels and are well below those of 1995, the projectˆs first year. Cover sprays for codling moth control averaged a bit less than one per block for the year, a slight drop from 1996. Just over 100 acres, mostly pears, received no covers at all in 1997. Five or more covers were used in the neighboring conventional blocks used for comparison. Most importantly, codling moth fruit damage remained very low (0.05% on average), declining from the already low levels of the previous two years. The maximum damage found was just under 0.4% in one block. Many growers will reduce Isomate C+ rates to about 200/acre in 1998, and some may also apply no covers to many blocks.

Pandemis leafrollers became a concern here in 1995, causing significant fruit damage in some blocks (0.23% on average). Since then, concerted control efforts have reduced damage to a negligible level of 0.03% in 1997. Most growers applied Lorsban with oil in the delayed dormant spray, followed with one or two Bt applications in the pink to petal-fall period. Other apple pests, including campylomma, tentiform leafminer, leafhoppers, aphids and mites, were also monitored. No significant differences with the comparison blocks were found, although parasitism rates for both leafhoppers and leafminers were consistently higher in areawide blocks. Damage to fruit by cutworm larvae was low, but larvae and leaf feeding were more easily found in 1997 than in previous years.

In the 80 acres of pears at this site, pear psylla populations remained lower throughout the season than those found in conventional blocks. This observation has remained consistent for all three years of this project. The areawide blocks have also consistently applied fewer insecticides for psylla than the conventional blocks. Psylla predators are often at equal or lower levels in areawide blocks, probably a reflection of there being less for them to feed upon.

1998 will be the fourth year of the West Parker Heights CAMP site, and all growers will participate again. All growers have recognized that codling moth damage is reduced and they have all indicated that they would use MD in their control programs even if using it increased their costs above those of a conventional program. This CAMP site may expand in 1998, as some neighboring conventional growers want in on the fun!

Howard Flat: This site near Chelan, WA, expanded considerably in 1997, adding 650 new acres in the nearby Chelan River area, farmed by 27 growers. In addition, the acreage of the one non-participating grower on Howard Flat was brought into the project, raising the total project acreage to 1,750 acres.

Codling moth populations continued their dramatic decline on Howard Flat. Seasonal catch in pheromone traps totaled but 0.8 moths/trap, a 50% decline from the previous year and a 91% drop from 1994, the first year of areawide control. Only 16% of the traps caught even a single moth. Cover sprays for codling moth control averaged below one per acre, with 30% of the growers applying no covers. In addition, the average number of pheromone dispensers (Isomate C+) used dropped below 300 per acre, with nearly 50% of the blocks treated with 200 per acre or less. Most importantly, fruit damage from codling moth at harvest was a barely detectable 0.01% on average, and was found in just three small neighboring blocks. One of these, the former non-participant, had close to 10% damage the year before; in 1997 this was reduced to 0.07%. The Chelan River addition in 1997 had codling moth population levels similar to those found at Howard Flat in its first year (1995). Average catch was 7 moths/trap/season, with second-generation catch averaging only 1.2 moths/trap. Codling moth fruit damage averaged 0.11%.

Overall leafroller populations, as determined by catch in pheromone traps, were similar to previous years, with a trend for increasing numbers of obliquebanded leafrollers and decreasing numbers of pandemis leafrollers. Fruit damage declined further on Howard Flat, averaging 0.14%. Chelan River had somewhat lower catches per trap, and caught far fewer pandemis than obliquebanded leafrollers. Fruit injury from leafrollers was quite low (0.01%).

Of greater concern for many growers was the damage from other pests, particularly stink bugs and campylomma. This fruit damage tended to occur in isolated and distinct sites. Within Chelan River, bug damage averaged 1.1%, but individual growers had over 9% campylomma damage and 7% stinkbug damage. Similar damage levels occurred in other orchards throughout this region, whether MD was used or not. Significant amounts of bug damage occurred within Howard Flat as well but at much lower levels, perhaps because the orchards there are more contiguous, with less border contact with the native vegetation that can serve as bug habitat. Cutworms were also a concern for some growers, damaging close to 1% of the fruit in a few blocks. Unfortunately, the primary cullage for most growers was caused by hail, the result of a widespread and violent storm that swept through the area in June. This was an especially hard blow for these growers as they had been devastated by a hailstorm in July of 1995 as well.

In 1998, all growers are expected to remain in the CAMP program. Reduced rates of Isomate C+ will probably be used by almost all growers, and many may apply no covers, relying upon trap catch to indicate any need for sprays. Codling moth trap density will be reduced to one per 5 acres in those areas with low or no catch for two years, such as the north half of Howard Flat.

Lake Osoyoos: "The Worms Are Almost Gone" is the apt title of the 1997 report for this CAMP site. With a combination of mating disruption, cover sprays, and the release of sterile moths from the Osoyoos facility, the poor codling moths havenˆt had a chance.

This project also expanded in 1997, adding close to 400 acres and 10 new growers, bringing the totals to about 800 and 24, respectively. All growers used Isomate C+ dispensers again, with all but two continuing to use them at the full 400 per acre rate. Sterile codling moths were released to all of the original acreage and a portion of the additional acres, beginning in early May and continuing until mid-September. This is a change from the previous two years, when steriles were available for second generation only. This year most growers in the original site applied no cover sprays, averaging just under 0.2 covers/acre/year. This is a result of the very low catch of wild moths in pheromone traps. Seasonal catch averaged 0.3/trap, versus 0.8 in 1996 and 4.3 in 1995. Fruit damage from codling moth was again very low, averaging 0.06% in the original acreage and 0.07% in the expansion orchards.

Leafrollers were a serious pest for many growers here in 1995, damaging close to 1% of the fruit at harvest. With this problem clearly identified, Lake Osoyoos CAMP growers in 1996 used a spray program relying upon two to three Bt sprays to reduce damage to 0.36%. Leafroller damage in 1997 averaged 0.37%, essentially unchanged from the year previous. The expansion blocks had higher average damage (0.64%) and the conventional comparison blocks were higher still (1.04%). There were few problems with any other secondary pests, other than a few isolated areas of light bug damage (campylomma and lygus).

The Lake Osoyoos growers are looking forward to 1998. With the continued release of sterile moths, few or no covers are planned, and pheromone dispenser rates will be reduced. Interest in the areawide program is great in the area, and the project may expand south to include 800 or more additional acres.

 

Seven New CAMP Sites Selected for 1998

Seven sites have been chosen to receive funding from the USDA-ARS for 1998. Each site will receive funding for one year only to be used to support the coordination, monitoring and information dissemination of an areawide control site. In brief, these sites are:

Rogers Mesa, CO: This site is on the western slope of the Rocky Mountains in Colorado, at about 6000ˆ elevation. Close to 600 acres of apples will be involved. Larry Traubel is the coordinator.

Prosser, WA: Located north and west of Prosser, this site could include over 1600 acres of orchard, primarily apples, and over 30 growers. Nan· Simone is the coordinator.

Moxee, WA: Some 700 acres of orchards and 6 growers are involved in this site located on the south side of the Moxee Valley, about 5 miles east of Yakima. Dave Gleason is the coordinator.

Othello, WA: The site is located along Bench Road, to the west and south of the city of Othello. It is expected to include 9 growers and close to 1300 acres of apples. Bob Thompson is the site coordinator.

Babcock Ridge, WA: Located several miles west of Quincy, this site contains just under 700 acres of orchards, farmed by 7 growers. Nick Stephens is the coordinator.

East Wenatchee, WA: Close to 600 acres are expected to be involved in this project in 1998, involving 12 or more growers. Located east of Pangborn Airport, this site had an areawide control project in 1997 coordinated by Stemilt Growers, with very good control of codling moth. Paul Nelson will be the siteˆs coordinator.

South Shore Lake Chelan, WA: This site is several miles east of the city of Chelan, involving 600 acres and 12 growers. They plan to share personnel with the Howard Flat project to save costs, and hope to combine the use of fenoxycarb (ComplyÆ) with mating disruption in their control program. Brian Hendricks will coordinate the site.

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

Partial Funding provided by: Washington State Tree Fruit Research Commission, U.S. Department of Agriculture-Agricultural Research Service.

AREAWIDE IPM UPDATE
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