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.

NEW apple maturity report, 09/14/09

NEW apple maturity report, 09/14/09: Snappy Mac, Rogers Red and Redmax McIntosh, Honeyrcrisp, Brookfield Gala. General comments on 09/14/09 apple maturity: all fruit tested picked at UMass Orchard, Belchertown. Fruit maturity is moving along rapidly, particularly McIntosh and Honeycrisp. There is less than a week left to pick McIntosh for CA storage. (September 19 to be exact in Belchertown.) Honeycrisp are at their optimum harvest maturity, but will soon start to go by and drop will become excessive unless fruit was treated with ReTain. Honeycrisp fruit should be kept at app. 60 degrees F. for 5-6 days after harvest before being put in cold storage at 38 degrees F. Gala has a bit to go but is adequate for first harvest. Background color change from green to yellow-cream is evident. Let's hope the sugars develop in Gala over the next week. Full report here http://bit.ly/10ILU5

Apple scab-resistance: Honeycrisp vs. McIntosh judged no contest

I have been collecting some yield data on an orchard planted in 2006* at the UMass Cold Spring Orchard in Belchertown, MA this past week. I can't help but observe how much more apple 'scab-resistant' Honeycrisp is compared to McIntosh. Now, this orchard received a 'normal' fungicide schedule to control scab, but, it was a very wet summer, so scab became more apparent on McIntosh fruit (pictured) as the summer wore on. I estimate 5-10% fruit scab on McIntosh. I observed no scab on any of the Honeycrisp fruit or foliage. It's clear Honeycrisp orchards can get by on a reduced -- not necessarily none -- fungicide spray program compared to McIntosh.

*Honeycrisp, and 'Rogers Red' and 'Snappy Mac' McIntosh on M106, M26, and B9 rootstocks planted to three systems (NZ central leader-3m between trees, vertical axis-2m between, and tall spindle-1 m between) with three replications.