by Terence Bradshaw

We’re in a bit of a quiet window for pest management in Vermont orchards. Apple scab primary ascospore release is done, and if you have no scab in the orchard, you’re done for the year managing that disease. For anyone with a scab issue, maintaining fungicide coverage every 10-14 days or after 2″ of rain will be important until terminal bud set when leaves and fruit become less susceptible to secondary infections. I’ve seen little fire blight, despite the infection periods predicted in the pest models. I’ve said this before- cut out any fire blight strikes as soon as you see them, and feel free to contact me to evaluate any questionable strikes. I have seen several instances of Nectria twig blight this season that look much like fire blight, but are caused by a relatively weak fungal pathogen. Nectria often infects winter-damaged wood, which I am seeing a lot of this year. The most notable characteristic that identifies Nectria compared to fire blight is that Nectria-infected shoots will have a very distinct delineation between dead (brown) and live (green) tissue at the base of the dead shoot. Fire blight shoot blight will typically show a gradation between dead and living tissue as well as water soaked cambial tissue in the area of visible infection. The only management technique for Nectria is to prune it out, and maintain the orchard with good pruning and nutrition to ensure good cold hardiness. Summer diseases such as sooty blotch/flyspeck and fruit rots are the main concern now. Dr. Dave Rosenberger’s comments from June 23, 1014 issue of Scaffolds provide good insight into managing these diseases. Take home message (read the article for specifics): Captan alone or with another material will likely be in your spray program every 2-3 weeks for the next month or two, especially if this wet weather continues.

Apple maggot traps should be hung any time now to monitor for this pest. I observed my first trapped apple maggot fly at the Hort Farm yesterday in an especially problematic block, so they will be flying in commercial orchards any day now. Other insect pests of concern potentially include obliquebanded leafroller and codling moth. skingsle ASAP.

-Terry

by Terence Bradshaw

Please see the attached itinerary for the June 30 Champlain Valley Orchard Tour. Cornell Entomologist Peter Jentsch will be with us on the tour to discuss summer insect pest management.

We will begin at 9:30 AM at Hick’s Orchard in Granville, NY, then travel north to Champlain and Sentinel Pine Orchards in Shoreham, VT. This will be a self-driven, caravan-style tour. We will provide drinks and light refreshments, but please plan on packing a lunch for the day.

RSVPs are requested, please email Sarah Kingsley-Richards with your name and the number of persons who will attend at: skingsle

150630_SummerOrchardTour.pdf

by Terence Bradshaw

Apparently I need to go away for a week for us to get any significant moisture, and boy did we get it. The good news is that apple scab ascospores should be all released now, so if you maintained good protection during the primary infection season, You should be done by now. If you have any question about fungicide coverage, be sure to carefully inspect the orchard for lesions that could cause secondary infections during the summer. Lesions from the May 28 infection period should be visible by now. The bad news is that no matter what was last sprayed, there is likely zero fungicide residue in orchards unless they were treated recently. Sooty blotch and flyspeck (SBFS)are the main diseases of note now, and will require treatment to manage them. Dr. David Rosenberger wrote a good summary article on SBFS management in the June 23, 2014 issue of Scaffolds. Fire blight infections should be visible in orchards by now. Please let me know if you are seeing this disease in your orchard. At this point, if you have it, the primary management strategy is to cut it out.
Codling moth eggs are hatching now, and insecticides targeted at larvae should be applied as soon as possible.
Results from apple thinner applications should be evident by now, and I am hearing from many growers that there is excessive fruit in their orchards. I do not have enough experience with ‘rescue thinning’ at this point to recommend it, your best option to reduce crop load may be to hand thin. Hand thinning at this point will have little effect on return bloom. For growers who are concerned about poor blossom bud development for next year’s crop, especially on biennial-tending cultivars (Honeycrisp especially), application of a return bloom enhancer such as Fruitone or Ethrel may be considered. Specific materials, rates, and timings are found in Chapter 11 of the New England Tree Fruit Management Guide.

by Terence Bradshaw

Please consider joining us for a tour of Champlain Valley orchards sponsored by the UVM Fruit Team, UVM Extension Risk Management Agency, Vermont Tree Fruit Growers Association, and Cornell Cooperative Extension on June 30, 2015. Final details are still being arranged, and an agenda will be forthcoming.

Cornell Entomologist Peter Jentsch will be with us on the tour to discuss summer insect pest management.

We will begin at 9:30 AM at Hick’s Orchard in Granville, NY, then travel north to Champlain and Sentinel Pine Orchards in Shoreham, VT. This will be a self-driven, caravan-style tour. We will provide drinks and light refreshments, but please plan on packing a lunch for the day.

More details will be coming soon. RSVPs are requested, please email Sarah Kingsley-Richards with your name and the number of persons who will attend at: skingsle@uvm.edu

TB

June 2, 2015

by Terence Bradshaw

We are coming out of the biggest apple scab infection period of the season in Vermont orchards, and despite model predictions, I and many others in the region are assuming that there were plenty of mature ascospores that were released since rains started on Sunday. For orchards that were recently covered going into the infection, you can assume that fungicides were washed off after the first 1.5-2″ of rain, and that there was no protection for the latter half of this rain event, nor for showers that are expected this weekend. Spray conditions look good to excellent from this afternoon through Friday. I strongly recommend coming in with a fungicide with kick-back activity (DMIs, SDHIs, or Strobilurins, check your spray guide for specifics) as soon as possible. As always, these materials should be combined with a protectant fungicide to increase efficacy and reduce the development of resistance.

Plum curculio is still active, so a final application of an insecticide may be appropriate in problem blocks. Codling moth egg hatch is still about a week away, so specific materials against this pest should be held out until 250 degree days have passed since the first moth capture, which we expect in another couple of weeks.

Fire blight strikes have been observed at the UVM orchards, likely from the blossom infection that occurred May 9-11. Scout your blocks carefully and remove any strikes in dry weather.

The window for chemical thinning id rapidly closing as king fruit approach 15 mm in size. Cool weather for the remainder of the week and cool, cloudy weather the last few days have allowed the trees to build up significant carbohydrate reserves that will making chemical thinners less active. If you need more thinning, apply carbaryl + NAA as soon as possible. Higher rates (1 pint cabaryl 4L, 4-8 oz/acre NAA) would be prudent in blocks which had heavy bloom and good fruit set.

I will be away at a conference next week, so likely will not send out updates. Next week may be the first that we’ll take a break in the spray schedule anyway, assuming that we get good spray coverage on this week and the rains that come are not the downpours we just experienced.

Good luck with it.