Healthy Fruit 2024 Vol. 32:1

THE WAY I SEE IT

Jon Clements

This will be my last stint as Healthy Fruit editor because Liz Garofalo will be taking over that enviable job beginning next week with a slightly new format and a publication day of Wednesday afternoon going forward. YOU need to subscribe to Healthy Fruit ASAP if you have not already done so to continue receiving HF in 2024 starting next week. Subscribe link below. We also plan to begin weekly noon Zooms (aka “lunch bunch”) either on Tuesday or Wednesday (TBD) the week of April 15. Otherwise, the weather is insufferable, although some may disagree, and green tip is finally here but it seems like it has been a looonnnggg spring already, maybe because we never really had a winter? Let’s hope for a return of some seasonable weather and a dry spell soon.

SUBSCRIBE to Healthy Fruit for 2024 here if you have not already done so: https://extensionsalesportal-umass.nbsstore.net/healthy-fruit-electronic-subscription

UPCOMING MEETINGS

April 10 (Wednesday) Fruit Twilight Meeting

Wednesday, April 10, 2024 - 5:00pm to 7:00pm

Honeypot Hill Orchard 18 Boon Rd. Stow MA

1 pesticide credit, light dinner served

April 17 (Wednesday) Fruit Twilight Meeting

Wednesday, April 17, 2024 - 5:00pm to 7:00pm

Clarkdale Fruit Farm 303 Upper Rd, Deerfield, MA 01342

1 pesticide credit, light dinner served

Save the Date
MFGA annual summer meeting July 10, at the UMass Orchard 

DISEASES

Liz Garofalo

Apple scab

The green tip date has been set for April 2, 2024 in Belchertown, MA. Remember, if you are using a decision support system(DSS), you will need to set your own biofix as the date the DSS models use typically does not quite align with field observations. According to both NEWA and RIMpro, the Belchertown orchard is experiencing spore discharge and a "slight" infection risk. 

Powdery mildew (PM)

If you experienced PM in your apples last year, keep a look out for shoots that are not opening as quickly as others. This can be an indication of a PM infection as the pathogen causes delayed growth in infected tissue. Removal of infected shoots will reduce the incidence of new infections.  

Fireblight

Use caution when getting out your copper sprays. Do not apply when conditions are cold and or wet as increased incidence of phytoxicity is of concern. Prune out overwintering cankers where practicable only during dry conditions.

INSECTS

Jaime Pinero

Pear psylla

A relatively small number of pear psylla adults have become active for the past two weeks. Pre-bloom management of pear psylla is very important to reduce the potential size of subsequent generations. One management strategy involves deterring egg laying by the insects using Surround WP at 50 lbs./A or oil applied at a concentration of 1-3%, depending on temperature and the level of green tissue present at the time of application. Both substances create a barrier film that inhibits egg deposition. For example, in trials conducted by Cornell University Surround WP at a rate of 50 lbs./A during the pre-bloom stage resulted in excellent reduction of first-generation nymphs through effective management of egg laying, with no observable clay residue on fruit at harvest. Surround alone is also useful when temperatures are too cold to safely apply dormant oil. Oil can be applied at the 1% rate from swollen bud through green bud, or 2 applications of 0.5% oil from green bud through white bud (flower parts are visible).

A delay of egg-laying also synchronizes the emergence of psylla nymphs, facilitating a more effective application targeting this life stage. Pyriproxyfen (Esteem 35 WP) causes the offspring of exposed adults to die during the egg stage or just after hatching. Pyriproxyfen applications do not reduce adult or egg numbers but will reduce nymphs when applied before they hatch. Cluster bud is a more effective timing than delayed dormant. From the label: “Apply a single application during the delayed dormant to pink stage of growth at 5 oz/A or make two applications from delayed dormant through petal fall stage of growth at 4 to 5 oz/A. Make application just before sustained egg lay is anticipated”.

HORTICULTURE

Jon Clements

It’s official, McIntosh green tip at UMass Orchard in Belchertown is April 2. DD’s (Base 43 BE) from January 1 to April 2 are 108, which matches up pretty well with the predicted green tip range of 99-144 DD’s. I note the NEWA apple scab model thought we reached green tip on March 31. It’s always early. Right now, historical probability of 50% damage to apples (April 3-June 30) currently at green tip is less than 10% per NRCC Climate Smart Farming. All good now, check in with me again in August. Significance of green tip, the apple scab ascospore maturity model starts ticking — don’t forget to update it in NEWA while you are logged into NEWA, you are logged in, right? — and believe it or not, the apple carbohydrate thinning model starts at green tip. The fun begins. Current bud stage photos here: https://ag.umass.edu/fruit/resources/bud-stages-photos

Got Accede SG? If not, get some and try it on your peaches, could save you a lot of time hand thinning. Note the formulation has been changed from a liquid to solid granular (SG) formulation this year. I’ll have more on peach thinning with Accede SG coming up.

Another formulation change, in this way the opposite direction, Chateau SW, formerly a dry formulation, is now Chateau EZ (hats off to Valent marketing department), a liquid. Chateau EZ has to be applied to apples before silver tip, bud break in peaches, just saying, it’s getting late to apply per the label.

 

Weird observation of the week, pictured above, exposed roots on apple trees planted last year, with all the rain we have had has washed soil away, it's always something...

BERRIES

Matthew Bley

Strawberries

Crop development should slow down with the cool, cloudy, and rainy weather that is predicted this week, but new growth may already be appearing. To check new growth, remove some straw from different spots in your field and look for new growth emerging from the crown. New growth can be identified by its tininess, yellow to lighter green color, and folded leaves. Plan to remove mulch soon as average soil temperatures continue to exceed 40℉ and new growth is coming in. Holding off on mulch removal may reduce and delay yield. Make sure to leave 0.5 to 1 inch of mulch on the strawberry row for some weed suppression and to serve as a barrier between newly forming fruit and soil.

 

Emerging strawberry growth. Pictured above in the middle are three sets of folded leaves ranging from pale yellow to green. To the right are the larger leaves of older strawberry growth. The background is long, light brown wood chips.

Blueberries

Blueberries seem to be well into bud swell, but there is still time for some last-minute cultural practices and preparations. 

Forsythia is in bloom here in Amherst, so keep an eye out for mummyberry apothecia forming beneath bushes after spring rains. Mulching to bury inoculum and raking to disrupt inoculum are proven cultural practices to manage the disease. If mummyberry infestation was severe last year, prepare by calibrating your sprayer, checking: NE small fruit management guide (https://ag.umass.edu/fruit/ne-small-fruit-management-guide/highbush-blueberries/diseases) to refresh yourself on FRAC groups, planning out FRAC group rotations, and ordering effective fungicides if needed. More on this next week.

Blueberry stem gall wasp (https://www.canr.msu.edu/blueberries/uploads/files/BlueberryStemGallWasp-WEB-final.pdf), overwintering structures can be found on 1-year-old shoots and should be nicely swollen and red about now, prune these out. Older structures are grey and have exit holes from which the previous generation emerged (image 2). Highly susceptible varieties, as established by Michigan State University, include Jersey, Northland, Pemberton, and Bluejay. If you grow these varieties, take another look for the gall while there is no foliage.

If scale was seen on fruit last year, scout for overwintering scale on older loose bark. Identification of scale can be difficult but look for waxy bumps on rough or loose bark. If you need help with scale identification please contact the team. There is no established threshold. If treatment is required, the treatment window closes at ¼ inch leaf opening (or V3).

Pictured above is an old blueberry stem gall wasp overwintering structure. The structure is ovoid and a light gray color with tiny dots randomly distributed. There are larger exit holes with slight cracking coming from them, these holes are where the insect had left from last year.

WEEDS

Maria Gannett

Glad to join the team as your new weed management extension educator.

Not much has emerged yet this season, but that should change here shortly. I have seen our usual perennial suspects:
- white clover (Trifolium repens L.),
- dandelion (Taraxacum officinale F.H. Wigg.), and
- mouseear chickweed (Cerastium fontanum Baumg.).

As well as winter annuals such as:
- purple deadnettle (Lamium purpureum L.),
- hairy bittercress (Cardamine hirsuta L.), and
- common chickweed (Stellaria media [L.] Vill.).

A reminder that the application window for some pre-emergent herbicides is closing. Some herbicides need to be applied before a specific crop growth stage is reached. For example, Chateau EZ (a.i. flumioxazin) needs to be applied before bud break in stone fruit and pears, and before silver tip in apples. In blueberries, Quinstar 4L (a.i. quinclorac) needs to be applied after dormancy but before budbreak. Other herbicides, like Zeus XC (a.i. sulfentrazone) and Devrinol 2-XT (a.i. napropamide) have a wider application window but work best when the soil is weed-free. See here for an article describing the pre-emergent herbicide research that Matthew and I are trialing out at the UMass Orchard this summer. (Ed. note, I don't see that particular project update yet, stay tuned.) We’ll keep you updated as the season progresses. Always be sure to use weed management techniques that target the weeds you have on your farm and to read and follow the label of any pesticide you apply.