In This Issue  

• IPM Mentoring Project
• Sulforix Trial 
• Codling Moth Program  
• Cane and Foliar Diseases  
•   
•   
• Breakfast Meetings 
• Raspberry Meetings/IPM Forum  The next beakfast meeting is scheduled for Wednesday, August 20th at 7:00 a.m. at Dutch Mothers Restaurant in Lynden. There is a lot to catch up on so be sure to mark your calendar today. We had a good turnout at the last meeting and are hoping for even more at this one.Apple Meetings/IPM Forum  The next breakfast meeting for apple growers has been postponed to Tuesday, August 19th.. It will be held at Dutch Mothers Restaurant in Lynden at 7:00 a.m. as usual. 

IPM Mentoring Project  

As discussed in past newsletters, 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.  

Scouting in raspberries is critical prior to harvest in order to determine whether a field is infested with spider mites, raspberry fruitworm, or clay-colored weevils. These pests when numerous enough can require treatment prior to the normal timing of pre-harvest clean-up sprays.  

Raspberry growers experienced the benefits of pre-harvest scouting firsthand and shared their thoughts with others as reported in last month's newsletter. The harvest period, just completed in the last week of July, is always a very busy time but was particularly stressful this year due to the rains in early July which created enormous disease pressure from Botrytis. This disease dominated the pest heirarchy this year and with good weather during the last few weeks of July, some growers were eventually able to pick their way through to some higher quality fruit.  

In spite of this hardship, scouting with these growers during and just after harvest has shown the following:   

Spur blight foliar lesions were most pronounced on fruiting laterals and it was not until late July that primocane lesions began to appear. 
  Brigade performed well for controlling black vine weevils and spider mites, with apparent minimal disruption of predator mites. 
  Predator mites have been common throughout harvest and predator:prey ratios remain favorable for continued biological control. 
  Yellow rust infection of primocane foliage was delayed until late in harvest and disease severity is low. 
  Botrytis infection levels of primocanes is much higher than usual. 
  

Scouting in apple orchards during the past month has focused on apple scab, spider mites, and continued use of the beating tray to monitor incidental insect pests and predators.  

Severe scab pressure this year has shown local growers how important it is to control early season primary scab. Due to wet weather conditions and slightly mis-timed fungicide sprays, 30-40% fruit infection has been observed in the most severely affected orchards.  

Field scouting has shown that spider mite populations in our test orchards are generally below treatment levels. Field evaluations have been confirmed by laboratory mite counting using a mite brushing machine in some cases where populations appear to be on the increase. We will continue this lab procedure in some of the orchards which have borderline spider mite or rust mite populations.  

We have been tracking the development of a likely beneficial bug (miridae family) using beating trays. Collections will be sent to specialists for identification later this summer. 

Raspberry 

Growers 

Predator Mites

Acari: Phytoseiidae

Typhlodromus spp. Amblyseius spp.

On-Farm Research   

 Sulforix Trial  

As reported in last month's newsletter, May evaluations of these plots showed the benefits of a delayed Sulforix application in reducing initial yellow rust infection of fruiting cane foliage. We plan to return to these plots in late August to do a thorough evaluation of spur blight, yellow rust, and cane botrytis incidence on primocanes. We would like to involve as many growers as possible in the evaluation of this project. Please contact me if you are interested in helping with this field evaluation and learning more about cane disease identification . . . . PHONE 384-9135.   

 Predatory Mite Release  

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. Preliminary results from mite brushing indicate once again that there is no significant benefit of releasing predator mites, even at these high levels, as a biological control tactic for spider mites. Predator mites were present in all plots prior to release at densities relative to the spider mite populations at the time. Predator mite density peaked in all fields in mid-July reaching almost 3/leaf in some fields and their prey (spider mites) have declined dramatically to very low densities at this time. It appears once again that Brigade did not significantly disrupt predator mite activity and likely assisted in controlling spider mites, which reached very high levels in late June in some fields but dropped dramatically by mid-July.  

We will continue to monitor these fields through August, when spider mites can build to damaging levels. At this point in time, the predator:prey ratios favor continued biological control in both treated and untreated plots. We will keep you posted. The dynamics observed in these plots parallels observations made from other raspberry fields this season which were not in proximity to predator mite releases.  

WSU Satellite Station Update - Patrik Herzog   

We at Washington State University Satellite Station in Lynden are currently working on some of our many chemical efficacy trials for this year. Right now we are focusing primarily on spider mites, namely the twospotted spider mite, the yellow spider mite, and a predatory mite, N. Fallacis. We have numerous fields in which we are monitoring mite populations following chemical applications; our data is still coming in. In addition to our spider mite projects, we are rearing three different root weevil species to monitor egg production and gestation period. Soon we will be starting chemical trials for root weevils and spider mites on strawberries.  

Our visiting Russian scientist, Natasha Bassangova, has been collaborating with Dr. Bob Vernon from the Pacific Agri-Food Research Center in Agassiz, B.C. regarding her survey of local predatory beetles for biocontrol of root weevils. Dr. Vernon has found that there are species of predatory beetles that exist in red raspberry fields near Agassiz, but interestingly Natasha has been unable to locate any of those same species in raspberry fields in Whatcom County. Natasha is researching the possible differences in climate and pesticide practices between the two areas in hopes of answering the question why those beetles do not exist in our local fields. We will let you know what we find.  

We are planning an open house here at the Satellite Station, on September 11th, to present our data and findings of this year. Mailings will be sent out near the end of August. All are invited. 

What's Buggin' 

Me Now?? 

Twospotted Tetranychus urticae Koch  

Spider Mites   

Twospot spider mite populations are at low levels in most producing raspberry fields as of the last week or so of harvest. Predator mites can also be found on leaves that are supporting small colonies of spider mites. It is important to scout fields a couple of times between now and early September to determine the situation in your field. Check a minimum of 10 primocane leaves per site in 4-5 sites per field and count the number of spider mites and predator mites at each site. Look on the undersurface of the leaf for spider mites and mite predators. A 10X handlens is helpful for magnifying these small critters. This sampling takes about 45 minutes per field and will provide valuable insight into what's happening in your field. One of the fields we just sampled under the mentoring program averaged 2 spider mites per leaf and 1 predator mite per leaf. That's a great predator:prey ratio. Contact the Bellingham WSU Cooperative Extension Office if you need materials to assist you in identifying spider mites or their predators.  

Cane and Foliar Diseases   

Botrytis primocane infections are quite common this year due to the severe disease pressure this season. Lesions on primocanes are brown in color (lighter than spur blight) and can be several inches long. They may be gray and moldy in appearance evidence of ongoing sporulation. Spur blight lesions on primocanes appear as a darker chestnut color usually beginning below the node where primocane leaves attach to the cane. These lesions are most common low to mid height on the primocanes. Yellow rust (uridia) is now present on primocane leaves but disease severity is generally low at this time.  

Most growers are applying post -harvest fungicide mixes such as Captan plus Benlate for suppression of botrytis, spur blight, and cane blight. Take note of fields with higher incidence of yellow rust. It is a good practice to delay cane tying in these fields until after leaf drop. This cultural practice should help reduce disease carryover. Growers should also select and prune out primocanes that are infected with botrytis once pruning begins. This is a good tactic to reduce botrytis disease carryover and to eliminate primocanes weakened by botrytis. 

Apple 

Growers  

Research 

Topics 

On-Farm Research  

The Nooksack IPM Project has been tracking mite populations in Apollo treated and untreated portions of Tom Sewell's orchard since late June. Based on his experience last season, Galas were treated with Apollo this year to prevent the buildup of European red mites (ERM). We are comparing these treated Galas to untreated Jonagolds, which usually don't have an economic spider mite buildup. Our counts show virtually no ERM in the Apollo treated area and very low populations of rust mites (less than 100/leaf). The western predatory mite, Typhlodromus occidentalis has been present at significant levels (.2 - .5/leaf) since mid July in the Apollo treated areas as well. In the Jonagold untreated areas, ERM is present but well below economic threshold. The population has been hovering around 2-5 mites/leaf and pretty low egg numbers as well. Rust mites reached about 300/leaf in late July but these are expected to decline soon with current hot weather. Predator mites are present at a similar but slightly lower density.  

Following a discussion of orchard mites at our last breakfast meeting, we have expanded mite brushing and lab mite counting to other orchardists to expose them to this pest management tool and to learn more about the spider mite and predator mite complexes in area orchards. It appears that most orchards have a pretty good balance of predators and spider mites, which indicates that our spray programs have not been too disruptive. However growers should watch Galas carefully as well as young orchards, which may not have significant predator mite populations to suppress spider mites. Some orchards also have very high rust mite populations and the reasons for this are not well understood.  

Codling Moth Program   

As of Friday, August 1, heat accumulation in area orchards was as follows:   

* Sewell: 1275 Degree Days - Custer   

* Gavette: 1275 Degree Days - Custer   

* Copeland: 1321 Degree Days - Nugents Corner   

This degree day information is based on the first reported CM flight or BIOFIX which occurred on May 12. Total degree days were reset to 200 on that date. Second generation flight started in late July(1200 DD). Trap catch should be watched closely between1200 DD and 1450 DD. If 5 or more moths/trap are caught during this period, then a spray should be applied according to guidelines in "The Orchard Pest Management Manual". If not, then trap catch is reset to zero and tallied up over the next 21 days using the same threshold. Refer to the Nooksack IPM Barn Chart for decision making tips. With the current weather, we are accumulating 120 - 140 DD per week. Make sure you have fresh pheromone lures in your traps if you are depending on them to assist in spray timing. They should be replaced every 4 weeks.   

For Information Contact:   

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