Saturday, November 3, 2018

New York, New England, Canada Fruit Pest Management Conference

I'm on a roll. So, in mid-October 2018 I was up in Burlington, VT with a group of fellow-minded (mostly tree fruit) Extension, research, and consultant folks from the New England states (mostly), New York, and our friends up north, Canada (mostly Quebec). This is the our 82nd get-together, believe it or not. I've been probably close to 25 times beginning with my work at University of Vermont and continuing with my 18 years at UMass, during which I don't think I have missed a year? There were just over 30 of us, as evidenced by this group photo:

Northeastern IPM Center Tree Fruit Working Group, 24-October, 2018.
Photo byCornell's Art Agnello, our facilitator at far left.
We reported on special orchard problems during the past growing season, gave research and Extension reports/updates, and much enjoyed a regional beverage tasting, all at the Bishop Booth Conference Center on the shore of beautiful Lake Champlain. You can further investigate this Tree Fruit Working Group on the Northeastern IPM Center website, including reports and research presentations. (2018 to be posted soon I hope.)

But we had a special guest, Peter Triloff, a consultant from the Lake Constance region of southern Germany. Peter was being hosted by Vincent Philion up in Quebec, so they came to the meeting togeher, and Peter gave an update on canopy adjusted spraying. Wow, kind of blew away some conventional wisdom I had, such as going slower equals better spray coverage (not necessarily) and that air-induction (AI) nozzles are NOT the way to go, because drift reduction, although important, should not be priority when spraying. What is priority? Better coverage while still controlling drift. AI nozzles do not give you as good spray coverage compared to regular hollow cone nozzles with finer droplets. So how do they achieve higher spray coverage with smaller droplets while controlling drift? Peter says by modifying the air flow to match the canopy, which includes throttling down while speeding up.
One screen of Peter Triloff's presentation at Interpoma as mentioned below
Now, there are many fine points, but there is one major talking point: radial fans are a disaster if we are talking tall-spindle type trees. (And why would we talk anything else?) A tower (vertical air flow pattern) is the only way to go. I certainly get the impression spray technology over there is way ahead of us. And they have restrictions, such as wind speed limits (app. 8 mph?), sprayer inspections, and full sprayer clean-out between tank mixes. Peter's talk also honed in on the money and time saving that could be achieved by speeding up while still maintaing good coverage. Diesel fuel savings too which they seem to be into out there. AND, pesticide use reduction by about 2/3 because spray is not going on the ground or drifting! Target the canopy and save money, time, and reduce pesticide use. What's not to like? Here is a presentation on this subject from 2014 given by Peter Triloff at Interpoma in Italy. The presentation he gave in Vermont was updated and quite thought provoking. Mostly, we could do a lot better with our spray application technology here in Massachusetts, New England, and the Northeast? I present my case:
















IFTA New Zealand 2018

I admit to being lame and not publishing a blog post in almost a year. It's been a busy year with lot's going on, so I ought to make an attempt to get back in the saddle. (No promises.) Will start with a big deal, I was lucky enough to spend almost two weeks in New Zealand last February with the International Fruit Tree Association. Mostly I want to share with you a photo album I put together, but here's a (very) quick synopsis of my trip.

IFTA New Zealand 2018 attendees.

First stop Napier, on the North Island. I liked the public water pool/hot tubs after a long series of flights that spanned two days. One-day IFTA Conference to kick things off, intro to New Zealand apple production and some pretty technical production talks. Of course you know NZ is now famous for Jazz, Pacific Rose, and more recently Envy but don't forget Granny Smith, Gala, and Braeburn also originated in New Zealand! Two full days or orchard tours in the Hawke's Bay apple growing region. Many highlights including NZ Plant & Food Research (Future Orchard Production System), Prevar, and Rockit apples. Very technical and detail-oriented apple orchards, apple quality is key given the money is in export apples. We had a day off with guided activity options, I chose a bike ride along the coast and sheep country topped off by lunch at a winery. With wine of course! Made the bike ride into a stiff wind back to point of origin kind of onerous, but overall the day was a great one.

Public pool/hot tub beachside in Napier. Sweet.

After a short Island hop courtesy of a chartered Air New Zealand flight we landed in Nelson. Nelson is a rather cool place with a downtown filled with shops, bars and restaurants. Two full days of orchard tours in Nelson/Tasman Region. Again, highly technical apple growing, including Drape Net demonstration, 2D apple canopies, and grafting. Another day off with a group trip to Abel Tasman National Park. Choice of activities, I opted for Catamaran ride. Needless to say it was great. While in Nelson, I also caught a glimpse of the "Crux" aka Southern Cross constellation one evening.

Dr. Greg Lang. You think he is enjoying the Cat?
Departing Nelson on bus, destination Christchurch, we stopped in Kaikura. Again, choice of group activities, I went swimming with dolphins. Whoaa, that was an experience, wet suit and mask/snorkel, flippers and all. Whisked off back of boat, saw dolphins, whistled back on boat. Several/many times. Exhausting, ever seen the movie "Open Water?" Thought crossed my mind.


OK, one day of orchard tour out of Christchurch to Timaru Region, one orchard, M A Orchards, first (and only?) Honeycrisp planted in NZ in 2012. Large red apples being harvested, bound for North America. Of concern was some significant drop. Reflective fabric in place. Very interesting.

Bin of harvested NZ Honeycrisp, 7-March, 2018

Thanks to IFTA, all our NZ hosts and sponsors, and Onward Travel for making it all a pretty seamless experience with good orchards, good food, good company and entertainment, good scenery, good recreation. And to WSU's Karen Lewis who did two rounds of hosting over a period of a month.  Every stop/activity times two. She has special skill, knowledge, and stamina to be able to go the mile (kilometer?), and we all appreciated her presence many times over.

Karen Lewis, fearless leader. The end is near...
And be sure to check out the photo album here...


Wednesday, January 3, 2018

Precision chemical apple thinning in MA in 2017

OK, I have been through this before, the whole measuring apple fruitlets thing and entering data into the precision thinning spreadsheet to determine if I needed to do more chemical thinning (or not) routine, you can read all about it here: http://jmcextman.blogspot.com/2016/06/precision-chemical-apple-thinning-in-ma.html But in 2017 I decided to ease the workload AND at the same time do more varieties. Yea, right.

To that end, I used four groups of dwarf apple trees -- Honeycrisp, Gala, Fuji and DS-41 (Pazazz) -- at the UMass Orchard in Belchertown, MA. These trees were either on M.9 or B.9 rootstock, and six to ten years in age, in other words pretty much settled down tall-spindle type trees planted three feet apart. The Gala/M.9 were tallest (at the top wire), the 10-year old Honeycrisp/B.9 the shortest (barely 7 feet).

Instead of doing the recommended 15 spurs per 5 trees, for 75 spurs total, I said to myself "surely 5 spurs per tree, 5 trees, 25 spurs total will be enough in these trees and give me a good enough idea of what's going on and save me a lot of work, right?" Yea, right.

I ended up making measurements three different times, and deciding -- likely w/o much input from anyone else, and probably not enough commiserating about it -- that after two chemical thinning sprays*, I was done. No more measurements, no more chemical thinning sprays. It looked kind of good, see Figs. 1-4 from the precision thinning spreadsheet.

*I think, can't really verify with spray operator, but it was something like petal fall carbaryl, followed by a carbaryl/Fruitone spray at modest rates, let's just say it was pretty much a "grower standard" for 2017. Pretty lame, huh?

Fig. 1 -- Honeycrisp predicted fruit set


Fig. 2 -- Gala predicted fruit set

Fig. 3 -- Fuji predicted fruit set

Fig. 4 -- DS-41 (Pazazz) predicted fruit set

Some explanation on what you are seeing in the Figures:
  • 2 and 3 on the x-axis are the measurement times, app. 7-10 days apart, after the first fruit measurement (which is not shown)
  • the blue-purple bars (y-axis) are the predicted number of fruit setting based on the measurements and fruitlet growth rate model
  • the green bars are the target number of fruits per tree, which was initially decided on when bloom clusters were counted; it was decided that 50 fruit per tree (60 for Pazazz, large fruit size an issue) was the target crop load, which is about 10% of all the flowers setting (app. 100 flower clusters per tree, times 5 flowers per cluster, equals 500 flowers, if 10% set equals a crop load of 50 fruit, right...admittedly a bit fuzzy?)
Now that you got it, well it sure looked to me like we were getting some pretty good thinning across the board with the second chemical thinning spray that was made between measurement 2 and 3. So, as already mentioned, enough was enough, right? Yea right.

I could tell by mid-summer that most of the trees were clearly overset. But I left them to harvest, and then picked and counted all the fruit off each of the five trees. Here is the average number of fruit left per tree (across the 5 trees) by variety compared to the target number of fruit and what the spreadsheet was telling me after the last measurement (see Figs. 1-4 above).

no. fruit at harvest
predicted fruit set
target no. fruit
Honeycrisp
180
133
50
Gala
132
120
50
Fuji
117
132
50
DS-41 (Pazazz)
80
88
60

Except for DS-41, all the trees had more fruit on them at harvest than what was predicted on the last measurement date and all had way more fruit than the target number. (I knew that about mid-July!) 

One other data observation before I get into what went wrong. I counted the number of fruit left at harvest on each of the 5 tagged spurs. (Except for Honeycrisp, it dawned on me this would be a good idea after I had already picked the fruit. D'oh!) The results are kind of interesting, because, think about it -- if five flowers, 25 fruit set potential, 10% (the already defined target) then there should only be 2.5 fruit left per 5 flower/fruit spurs counted. Or 12.5 fruit per 25 clusters counted (125 fruit potential). My results on the 5 trees (25 clusters) are: Gala, 21 fruits left; Fuji, 16 fruits left; DS-41 (Pazazz), 11 fruits left. Remember, there should only be 12.5 fruits left. This somewhat mirrors the results above, in that DS-41 actually had the best thinning compared to the others. I could say more about this, but suffice it to say the flower clusters I tagged and picked to measure fruits were pretty representative of the end result.

OK, so what went wrong here? I have several (five to be exact) observations:
  1. How often have you over-thinned using chemical thinners? my experience is the first time you think you have thinned enough, hit them again with another chemical thinner application! (Caveat, watch the weather forecast if heat and clouds are forecast, be more careful.)
  2. Maybe using just five spurs per tree is not a good (big?) enough sample? if one or two spurs per tree are "duds" -- meaning they are not representative of all spurs on the trees, maybe they are damaged and/or readily shed their fruitlets? -- then it is going to throw the whole prediction off? Next time (if there is one) I will look at a minimum 10 spurs per tree (or 5 spurs over 10 trees?); I've had this issue/theory before...
  3. If after the last measure, the bar chart is still showing more fruit than the target, chemical thin again? Only when the bar shows less fruit than the target can you stop?
  4. You could always hand thin to the target fruit number to be on the safe side :-)
  5. Maybe the predicting fruit set model needs some kind of revision? But I will defend it here, because I introduced a lot of error into my procedure in an attempt to make it easier and do more; shortcuts are not good in this case, maybe?
Speaking of shortcuts, I would like to point out that I procured an inexpensive ($80) Bluetooth caliper on Amazon and paired it up with a custom spreadsheet I developed on my iPhone to enter data automatically in the field (Fig. 5).

Fig. 5 -- using a Bluetooth caliper and iPhone to enter fruit growth measurement data

It worked OK, just OK. I had to keep an eye on it to make sure it recorded data properly. If just one observation was skipped, then all the entries from thereon would be off, which would not be good. It has to be drop-dead reliable/accurate to be really useful. Needs work. Speaking of which, with all the talk about machine learning now, why not an app that can snap picts of fruit clusters and analyze which fruitlets are growing (or not)? I don't think that is too far-fetched?

Where do I/we go from here? As I've said before, it is a useful exercise to get out and measure fruitlet growth to help assess what is going on with your thinning program. And if you largely grow solid blocks of a few varieties, by all means go whole-hog and fully follow the procedure outlined here. It will work. Unfortunately, if you have many discrete blocks (tree age, variety, site, etc.) it's just too onerous/time consuming to implement the procedure in all blocks? (But do it in high value blocks, don't waste your time with McIntosh...) What's really needed is a bullet-proof way to measure and enter data quickly (and accurately) w/o having to employ too much man/woman power? Ideally in a mobile package, that also gives immediate feedback? Perhaps a chemical thinner spray has to be made sooner than later (because of weather conditions?) and having that immediate feedback would be useful (vs. having to go to home/office and entering the data into XLS spreadsheet)? Can we do that? I understand Cornell folks are working on an app that might help, keep your eye out for it in 2018. I just hope it is simple enough to be truly useful. I have some say, I am a beta-tester for Jaume and Poli at Cornell...

Alas, chemical thinning decisions are never "simple," are they? Good luck in 2018...