May 6, more on fire blight

May 6, 2015

Hi Fruit Growers,

The fire blight threat looks very real. (See fire blight models at http://web.uri.edu/ipm/ under Orchard Radar.) This pre-bloom heat and predicted heat means fire blight bacteria is multiplying and can infect open flowers. Fire blight needs open blossoms and moisture, once there has been enough heat to build up the inoculum. Looking at the CougarBlight model on Orchard Radar (AgRadar), fire blight risk is EXTREME for May 10,11,and 12 for Providence County. The threat is much less in Newport County and other cooler areas. Sounds like apple flowers will start opening on Thursday or Friday, so there will be many open flowers by Sunday. Even if we don’t get rain, fire blight can infect flowers when there is dew or water applied to trees for spraying or irrigating. Do not use overhead irrigation during bloom.

I think most growers in Providence County should apply streptomycin on Sunday or Monday. Use no less than 24 ounces per acre and plan on adding 1 pint of Regulaid per 100 gallons of solution. LI 700 should work as well as Regulaid in helping get streptomycin into flowers. If additional strep sprays are needed do not add Regulaid or LI 700 to later strep sprays. Do not apply Captan for at least 7 days after spraying Regulaid or LI 700. When spraying strep it is best to spray under slow drying conditions, such as in the evening.

As I’m sure you know, the next time it rains, many apple scab spores will be released. Keep your trees well protected with fungicides. Spray strep alone – separate from your other sprays.

Remember, there is a small fruit twilight meeting at Sweet Berry Farm on May 13. Let me know if you need more information.

May 20 is the next tree fruit twilight meeting at Tougas Family Farm, 234 Ball St., Northboro, MA. 5:30 PM. 1 pesticide re-certification credit.

I realize fire blight is very stressful. Please feel free to email, call or text me throughout the weekend. I’ll be busy at my niece’s wedding on Sunday starting at 3:00, but up until then I’m available.

Gosh – I didn’t say one thing about winter moth!

Heather