Petal fall pre-discussion

By Terence Bradshaw

May 21, 2017

Most Champlain, Connecticut, and Taconic valley orchards are at petal fall or quickly approaching it, which means the management needs will ramp up quickly- insect and disease management; nutrient application, mowing/herbicide/cultivation; and, of course, thinning. I’ll be wrapping my head around thinning options in the next few days, but for now, virtually every orchard should receive a petal fall application of carbaryl or, if organic, lime sulfur to aid in thinning. Like every odd-numbered year since 2011, this looks like a heavy crop, and your best bet for a good crop next year is to take 80+% of it off now. This is not a year to be shy with thinners, but also recognize that foliage that developed during cool, cloudy weather, as well as trees that were drought-stressed last year, will respond more to thinners than non-stressed trees. On the other hand, sunny to partly cloudy, seasonably warm (not hot) weather like we’re expecting this week reduces the carbohydrate deficit in trees which is what drives thinning treatments, so we really can expect a fairly ‘normal’ thinning season overall.

That said, I will reserve specific recommendations until after Tuesday’s Petal Fall/Thinning meeting in New York, which all are invited to and which was discussed in a previous message. Wednesday looks like a decent spray day anyway, so I expect we’ll have a better handle on things by then.

I hope to see many of you in the Chazy/Peru (NY) area Tuesday,


Where trade names or commercial products are used for identification,

no discrimination is intended and no endorsement is implied.

Always read the label before using any pesticide.

The label is the legal document for the product use.

Disregard any information in this message if it is in conflict with the


The UVM Tree Fruit and Viticulture Program is supported by the

University of Vermont Agriculture Experiment Station, a USDA NIFA E-IPM

Grant, and USDA Risk Management Agency Funds.