In This Issue  

• Project Update 
• IPM Mentoring Program 
• Sulforix Trial 
• Codling Moth Program  
• Apple Scab  
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• Breakfast Meetings 
• Raspberry Meetings/IPM Forum  The next breakfast meeting has been postponed until harvest is complete, probably in mid- to later August. We realize how busy growers are during the harvest period. The next meeting date will be announced.Apple Meetings/IPM Forum  The next breakfast meeting for apple growers has been postponed to Tuesday, July 15. It will be held at Dutch Mothers Restaurant in Lynden at 7:00 a.m. Timely topics will include management of second generation codling moth and mite counting procedures and recordkeeping. 

Project Update  

Funding  

Washington State University has just signed a contract agreement with the Department of Ecology extending the Nooksack IPM Project for its third and final year. Work under this project will continue through this season and be wrapped up probably by June of 1998.  

IPM Mentoring Project    

As discussed in last month's newsletter, a key focus of the Nooksack IPM Project this season is to assist selected raspberry and apple growers with season-long, regular, field scouting which forms the basis for their pest management decision-making. These growers shared the experience with others at the last IPM breakfast meetings as part of their agreement to mentor (tutor or coach) other growers. Their comments included the following:  

One raspberry grower applied two sprays for western raspberry fruitworm last year, but was able to control the insect with a single spray this year. This was due to the increased knowledge gained from scouting with a beating tray to determine when fruitworm beetles were present. This same grower now has a better grasp of both insect and disease identification, which comes through regular scouting in the field. Another grower commented that his fields continue to come up "clean" for insect pests which reinforces his belief that it doesn't pay to spray by calendar.  

A third raspberry grower expanded and intensified the scouting to the rest of his acreage in order to make more informed decisions about clay-colored weevil, raspberry fruitworm, and yellow rust management. This investment of about three hours of scouting paid off by allowing him to identify blocks which required treatment and those which did not.  

Apple growers comments were along the same lines. One reported that the scouting report serves as a record that can be used to compare pest populations from one year to the next and that spending 45 minutes to an hour to systematically scout a block is time well spent. Another grower felt that scouting is helpful because it gets her out through the orchard in a short period of time and in a systematic way, which provides a clearer picture of pest incidence and distribution through the entire orchard.  

The common thread found in these comments is that by scouting fields on a regular basis we gain knowledge, and there is an expression that "knowledge is power". Growers are discovering the power of regular scouting which is the foundation for Integrated Pest Management. 

Raspberry 

Growers 

Predator Mites

Acari: Phytoseiidae

Typhlodromus spp. Amblyseius spp.

On-Farm Research   

 Sulforix Trial  

We discussed the initial results of the Sulforix trials at last month's breakfast meeting. This is what we have seen so far. The standard timing of Sulforix applications provided 30-40% reduction in initial yellow rust infection, but delaying the Sulforix application until shoot growth was 2-3 inches and reducing the application rate provided 70 - 80% reduction in initial infection by this disease. It appears that the delayed timing this season was better synchronized with disease activity and thus provided superior control. There was some initial phytotoxicity associated with the delayed timing, but by late May there was no difference in lateral length, number of leaves per lateral, or number of flowers per lateral between the untreated plots and those that received both standard and delayed applications. This indicates that the plants were able to compensate for any initial damage and any negative impacts on yield are unlikely. We will keep watching these plots through harvest. It remains to be seen whether this reduction in initial yellow rust infection has a significant corresponding reduction in later season disease development, but results so far look pretty interesting.   

 Predatory Mite Release  

The Nooksack IPM Project is providing technical assistance to growers to further evaluate a biological control tactic for spider mite control. This involves the field release of the laboratory-reared predatory mite, Amblyseius fallacis. This is the same species of predatory mite which is naturally occurring in our Whatcom County raspberry fields and which, on occasion, provides economic spider mite control. This project is being partially supported this season by a Western Region Sustainable Agriculture Research and Education (S.A.R.E) grant.  

Predatory mites were released in four raspberry fields on June 19th and 20th. We are experimenting with higher release rates this season since we saw no benefits from the rates used last season. The lowest release rates are 15,000 predatory mites per acre which is twice the amount used last year. Two fields with spider mite populations averaging 3 mites/leaflet were treated at this rate. The higher release rate, 30,000 predatory mites per acre, was applied to two fields which harbored significantly more spider mites at the time of release. These fields will be evaluated every two weeks or so during the season to determine the effectiveness of this strategy and the impacts of pesticides on both spider mites and predator mites. 

What's Buggin' 

Me Now?? 

Black Vine Weevil

Otiorhynchus sulcatus 

Black Vine Weevil   

Emergence of summer adult black vine weevils began in mid-May as usual and has been on the increase during the past two weeks. Most of the population is in either the pupal or adult stage with few larvae remaining in the soil. The Satellite Station recorded the first eggs from summer adults on June 23rd. This means that pre-harvest sprays, which are scheduled in many fields this week, should be well synchronized to control adults before the majority of them are laying eggs.  

Spider Mites

Twospotted Tetranychus urticae Koch  

Spider Mites  

Spider mite populations are quite variable between fields. Populations were slow to develop this year in most fields but increased rapidly in some fields during the first couple of weeks in June. With the cool weather, they have done little damage but egg counts are quite high in infested fields. Also with the cool, rainy weather, growers have had few days warm enough to apply Vendex, which is most effective when used on a warm (70F) day. Our scouting and reports from growers indicate high predatory mite populations this season in many fields. We will be collecting and brushing leaves from some fields which were recently treated with Vendex and will report our findings as the season progresses. Make sure to scout new fields for mites; many growers are reporting high counts in these fields.  

Yellow Rust  

Secondary yellow rust infections (uridia) were first observed on fruiting lateral foliage during the first week of June or thereabouts. In spite of wet weather, disease incidence seems quite low with infections restricted primarily to leaves on fruiting canes. As primocanes continue to grow through the major yellow rust infection zone (near the wire), they will likely be most susceptible to infection. We are watching yellow rust development closely this season in coordination with Dr. Pete Bristow and will keep you informed. 

Apple 

Growers  

Research 

Topics 

On-Farm Research   

As an extension of the IPM Mentoring program, we will be collecting leaves from cooperating orchards for mite brushing and counting when field visits indicate that spider mite densities are approaching treatment thresholds. This will be particularly useful to track rust mite populations as well as European red mite and predator mite levels. We have also taken initial samples from the Sewell orchard to compare mite populations in Apollo-treated and untreated areas. These samples show quite a reduction in rust mite and European red mite density in Apollo-treated blocks. These blocks will be checked regularly throughout the season. 

I have been following anthracnose canker development closely on a few trees at the Copeland orchard this season. My observations reinforce the experience of some growers, which is that the expression and development of visible summer canker lesions can be spread out over several weeks, if not months. Therefore, don't assume that you can remove all cankers with a single trip through the orchard before trees have fully leafed out in May. It is easier to see them at that time, but others can develop quite rapidly and can go unnoticed as trees leaf out. I have also been watching some very small reddish lesions (1/8" diameter) which were evident in early April; these have not expanded since that time. We should hear from Dr. Jim Rahe of Simon Fraser University regarding his canker research proposal soon after his return from the Okanagan region in July. 

Codling Moth Program  

As of Friday, June 20, heat accumulation in area orchards was as follows:  

Apple Scab  

This disease is rearing its ugly head this season in many area orchards. Primary infection was not controlled adequately in many orchards and we are now seeing secondary infection of both fruit and foliage and less than desirable control with some eradicant fungicides. Here are some tips to remember when protecting fruit and foilage from secondary infection based on review of the literature and recent conversations with Alan Jones, Michigan State University:  

Geoff Menzies, Project Coordinator 
Phone: (360) 384-9135 
e-mail: gmenz@coopext.cahe.wsu.edu