#iFruittree

The International Fruit Tree Association (#iFruittree) is meeting in Grand Rapids, Michigan, February 27-March 3 for it's Annual Conference. The Conference includes 2 days of speakers and 1 day of orchard tours in the apple production region near Grand Rapids. Here are some take-home messages from selected speakers, and hopefully at least

John Palmer "Apple and Pear Tree Physiology, What Have We Come Up With?"
Key concepts to understand:
Carbon acquisition -- light into total dry matter = linear relationship
• site factors; latitude; cloudiness; frost-free period
• tree factors -- leaf area index; tree height; row orientation; tree width; cultivar
• light interception sets the upper limit for production

Harvest index: total dry matter harvested in fruit (up to 70% possible)
• commercially actually less: why? young trees; biennial; size profile
• management changes have increased harvest index: dwarfing rootstock, minimal pruning, branch manipulation; PGR's
• "We can achieve up to 70% harvest index at maturity"

Fruit quality - think of as "hydrated dry matter ready to eat, attractive, good flavor, saleable, etc."
• shade decreases: fruit weight, red color, SSC, flower bud number, fruit set
• "shady business is to be discouraged in the orchard for more reasons than one"
• never forget link between light and fruit quality

Light interception and distribution; maximize use with minimum misuse: "every bud counts"

Future challenges of "precision horticulture"
• every bud counts
• improved rootstocks
• increased automation
• consistent high fruit quality at POS
• increased development of multidisciplinary teams including molecular biologists
• orchard systems in a wider context -- sustainability and carbon footprint

Steve McCartney "Flower Bud Formation in Apples and Strategies to Help Break Biennial Bearing Habit"
A successful post bloom thinning program in itself not enough to increase return bloom in some varieties
Flower bud initiation: 60-120 DAFB depending on variety (later than I though?)
Use of bio-regulators NAA and ethrel can increase return bloom
Summer NAA: four bi-weekly at 5ppm beginning 8 weeks after bloom
Pre-load (for stop-drop): 5 ppm NAA weekly preceding harvest
Ethrel; single app six weeks after bloom (rate is variety dependent)
What about 5ppm NAA with cover spray every 2 weeks? (Question: simple, but effective?)
More research needed!

Duane Greene "Predicting Thinning, Fruitlet Model"
Greene received the iFruittree 'Researcher of the Year' Award (bio and pict)
Has developed predicting thinning procedure (with colleagues) based on assessing fruit growth rate after chemical thinner application to determine the need for more thinning. Directions available on-line and Excel spreadsheet-based form to run the model.

Terence Robinson "Predicting Fruit Set, Carbohydrate Model"
Basic question: can we predict chemical thinning response using environmental variables?

Factors that affect thinning/final fruit set
• chemical thinner concentration
• application process: uptake, leaf environment, cuticle thickness
• sensitivity of the tree: bloom density, initial set, leaf quality, previous yield history

• temperature, sunlight, tree vigor

Carbon-based hypothesis: fruit sensitivity to chemical thinners primarily a function of carbon supply available for fruit growth from both current production and reserves: temp and sunlight influence trees carbon production; trees more susceptible to chemical thinners when carbon supply is limited and vice-versa

Carbohydrate model
• sunlight + temperature used to calculate photosynthesis = carbohydrate available
• temperature affects carbohydrate demand (higher temperatures more demand via respiration and growth)
• supply vs. demand determines balance (thus, surplus or deficit)

2009 experience:
• Western NY (Lake Ontario): no carbohydrate deficit during thinning window; growers had huge hand-thinning bill; multiple applications necessary to thin Gala
• Eastern NY (Hudson Valley); had some deficit and surplus during thinning window; thinning during deficit worked well

"Optimum thinning level" needs to be developed and visualized as target

Future work needed; test models (relies on good weather forecasts); develop a thinning prediction table; simplify carbohydrate model

Stefano Musacchi "High Density Planting Systems for Apple and Pear"

HDP High Density Planting (HDP, VeryHDP, UltraHDP)

Basis for HDP

• downsize canopy volume and tree height

• pears: quince rootstocks (MC, MH, Adams)
• apples: M.9

Practices
• pre-formed nursery tree (knip-boom)
• root cutting
• ridge planting
• Plant Growth Regulators (apogee; auxin and ethephon; GA's; Promalin)

Production always a problem (lower) in the lower canopy

Quality more important than total yield; yield increased only to a point before quality suffers

Latest development: Bibaum apple nursery tree -- dual leader tree developed from double chip bud or bench graft; obviates need for canopy formation; productivity same as single but with less trees; quality equal or improved

#MAFVC

I attended the Mid-Atlantic Fruit & Vegetable Convention last week (Feb. 2-4) in Hershey, PA. The Convention is a collaboration of the State Horticultural Association of Pennsylvania, the Pennsylvania Vegetable Growers Association, the Maryland State Horticultural Society and the New Jersey State Horticultural Society. Penn State University, University of Maryland and Rutgers University Cooperative Extensions all assist in organizing the three days of educational sessions. The Convention has become one of the premier grower meetings in the Northeast with about 1,800 attendees.

While there I ‘tweeted’ to my Twitter. As you may (or may not) know, Twitter posts are limited to 140 characters, i.e., they are brief. So, what follows are my ‘tweets’ from #MAFVC with a little more elaboration than Twitter allows. :-)

• Easier to define what is NOT sustainable (soil erosion) than what is sustainable - David Granatstein #mafvc

Granatstein is with the Center for Sustaining Agriculture & Natural Resources at WSU’s Tree Fruit Research and Extension Center in Wenatchee. After trying to explain what IS sustainable agriculture, which most parties agree is farming that is environmentally, economically, and socially sustainable, Granatstein said it is a lot easier to provide examples of what is NOT sustainable agriculuture. Clearly, he said, soil erosion is not sustainable. Agreed?

• Pests of increasing importance with 'soft' pesticide programs: PC, SJS, WAA, plant bugs, borers, EAS, and AMF. Dave Biddinger #mafvc

Biddinger is a long-time partner with entomology researchers (including Larry Hull) at PSU’s Biglerville Fruit Research & Extension Center. ‘Soft’/reduced-risk pesticide programs typically use newer chemistries targeted at controlling specific insects (usually the moth larvae fruit-feeders: codling moth, oriental fruit moth, oblique-banded leafroller, etc.) in lieu of broad-spectrum insecticides (organophosphates, pyrethroids, etc.). Mating disruption (MD) is also commonly used. Unfortunately, the softer pesticides and MD are letting certain pests ‘slip through’ and build up in orchards, resulting in more incidental but nonetheless important fruit and tree injury from Plum Curculio, San Jose Scale, Wooly Apple Aphid, European Apple Sawfly, Apple Maggot Fly, etc.

• Only thing more contagious than passion, ironically...is the lack of it. Harold Lloydd #mafvc

Lloyd was the inspirational and entertaining general session speaker “Am I the Leader I Need to Be?”

• #1 Worker Protection Standard infraction - failure to realize covered by WPS. Jim Harvey, PSU #mafvc

The Worker Protection Standard (WPS) is a federal regulation designed to protect employees on farms, forests, nurseries, and greenhouses from occupational exposures to agricultural pesticides. As a rule of thumb, all non-immediate-family members who work in a field or site that is within 30 days of a pesticide’s Restricted-Entry-Interval (REI, see ‘Agricultural Use Requirements’ on the label) and who receive compensation (of any kind, does not have to be money) are covered by the WPS. Hence, all requirements of the WPS -- including training, central posting, pesticide application notification, providing personal protective equipment, etc. -- must be followed by farm owners/operators/employers and (hopefully) employees.

• 20th century IPM 'Industrial Age, time for another poison' vs. 21st century IPM 'Information Age, what management action, and optimized combination of tools.' John Wise MSU #mafvc

Wise, of Michigan State University’s Trevor Nichols Research Station says pest management is becoming much more complicated with new pesticide chemistries, which are more insect- and application timing-specific to be effective. Hence, the need to have more information about the pests current status, such as life stage and abundance, are necessary to be effective in this new ‘information age’ of pest management. Tools used to collect this information include research, weather monitoring, and pheromone traps. Growers are going to need help assimilating this information into effective pest management decisions.

• Trying to use new chemistries on a calendar-based spray schedule is not going to be economically sustainable. J Wise #mafvc

Again, growers are going to have to time spray applications that target specific insect(s) at specific life stage timing vs. broad-spectrum applications on a fixed schedule or ‘time for another poison.’

• Maxcel @ 200ppm effective at reducing fruit set (and hand-thinning time) in heavy-cropped Asian pears. Dan Ward #mafvc

Asian pears can set heavy crops, requiring labor-intensive hand thinning to produce large fruit that the market requires. Colleagues Dan Ward and Win Cowgill of Rutgers University have demonstrated that the apple and pear thinner Maxcel can be an effective tool under the right conditions for thinning Asian pears.

• Fruit quality and yield are directly related to light interception and management-trees are solar collectors. Kevin Day #mafvc

Day is an extension specialist/researcher at UC Davis/Kearneysville. He gave the Ernie Christ Memorial Lecture -- ‘Training Systems in Peaches and Their Costs.’ The more light you can intercept (and distribute) by the orchard canopy, equals higher fruit yield and better fruit quality. We all know that, right? Oh wait, see next post. :-)

• Short [peach] trees had greater ability to size fruit than large trees, yield did not suffer (need 70% light interception). K Day #mafvc

Interesting, because Kevin and his colleagues in California had been promoting the perpendicular-V peach planting and training system, which normally has tall (12-14 foot high) trees. But, he showed when the canopy grows together at the top, approaching 100% light interception, yield and quality did not increase above an orchard that is intercepting 70% light. Therefore, they are cutting perp-V and quad- and hex- peaches down to 8 foot height, while maintaining yield and quality compared to taller trees. In fact, fruit were larger in the shorter trees.

• Bubble gum plum TM a winner according to Paul Friday http://flaminfury.com/?a=PG:448 #mafvc

Enough said?

• Our biggest limiting factor is to fill the space quickly (re. hi-density apples). Chris Baugher #mafvc

Chris runs Adams County Nursery's production orchard. When planting young, hi-density apple orchards using 3 to 4 foot spacing between trees, to make the economics work you need to fill the space between trees quickly (in 1-2 years) and begin producing fruit. Factors such as nursery tree quality, site prep, promptly supporting and irrigating, N fertilization, etc. need utmost attention.

• 2.8% leaf N for peaches ideal. K Day #mafvc

This is a little lower than what we typically recommend in the east, that is 3.5 to 4%. Of course California is not the east too. Something to think about, could we have somewhat firmer fruit at mature harvest and/or overall better fruit quality and yields with N a little lower. I might try it.

• Use monoammonium phosphate (MAP) @ 1/3 lb per tree at planting -- trees get off to much better start. K Day #mafvc

Phosphorous promotes root growth -- much work has been done on using supplemental P when planting new orchards. Highly advised for all new peach and apple orchards.

• Monitoring with pheromone traps the basis of IPM. Larry Hull #mafvc

Hull is a PSU guru on insect management, particularly lepidopteran pests. Models that use a biofix -- typically when a certain number of adult moths have been captured or first appear -- are increasingly being used to time targeted pesticide applications. See the obliquebanded leafroller model.

• Automated pheromone traps that send results by e-mail where we are headed. L Hull #mafvc

Pheromone traps that take pictures of accumulated moth trap captures and automatically e-mail (via wireless I presume) the results? I like it. Next step, just compute whether the threshold has been met or not -- that is all the end user needs to know. You heard it here first. :-)

UMass Video Fruit Advisor, October 22, 2009: PAD Analysis for apple scab

Reducing overwintering apple scab inoculum using fall-applied urea and leaf shredding

I was (October 20-21) at an annual meeting of tree fruit entomologists and pathologist in Burlington, VT. After what was a high-pressure apple scab year, it's likely there is some (or a lot) of scab out there in the orchard which will be the source of infection for 2010. All things being equal, the more overwintering scab inoculum the higher the scab pressure will be for next year. So, if you can take some steps to reduce the inoculum now -- like right now -- you can help yourself out for next year when it comes to managing scab. There was pretty much agreement on taking these two steps this fall to significantly reduce (up to 90-95%) the amount of overwintering scab inoculum:

• First, spray your apple trees right now with 50 lbs. of urea (spray urea, 44 lbs. is the actual recommended rate, but hey, 50 won't hurt and that is the bag size) per acre in 100 gallons of water while the leaves are still on the trees. Contrary to popular belief, this will not impact winter hardiness. Just keep in mind you are adding app. 23 lbs. of actual nitrogen per acre to the orchard, so adjust your fertilizer program accordingly.
• Second, flail mow/chop the orchard as late as you can and when the majority of leaves have fallen from the trees. Sweep or blow leaves into the orchard middle from within the row is helpful so that the majority of leaves can be chopped/shredded.

Doing these two integrated apple scab management practices this fall will help to reduce the number and intensity of fungicide applications and go a long way towards making your overall scab management program in 2010 a success.

Thanks to Bill MacHardy for doing the research on these practices.

Also see F-134 Reducing Apple Scab Risks and Saving Scab Sprays on umassfruit.com.

UMass Video Fruit Advisor-October 12, 2009: Crimson Topaz Apple

UMass Video Fruit Advisor, September 30, 2009: Liberty apple

NEW apple maturity report, 09/29/2009

General comments on 09/29/09 apple maturity: Empire, except those treated with ReTain, are ready for start of harvest. Pick over the next week. ReTain-treated Empire could go another week. Royal Empire (left) looks real nice, although fruit size is lacking on these rather weak trees on B.9 rootstock planted 2 feet apart. McIntosh and Honeycrisp harvest should be complete by now. I expect Golden Delicious, Mutsu, and 'Red' Delicious will be ready to pick the first full week in October (next week). Full report here.