Bloom this year has been erratic - some pears are almost done, apples still closed up. This makes me wonder about the best time to do the streptomycin spray, which I understand should be done at bloom. But - full bloom? Would petal fall be too late?
it needs to be done anytime flowers are open if you have had 3-5 days of warm weather and rain or heavy dew is predicted within the next 24 hrs. At my location we have a lot of warm wet weather during bloom so I basically end up spraying ahead of almost every rain event. Once I see decent fruit set I pick off all of the remaining flowers and dont let anymore open so I can stop spraying. I have had very minimal fireblight since implementing this approach, but then again fireblight is so unpredictable that maybe I have just been lucky. Although I suspect not because I have seen plenty of it on callery pears in the neighborhood, but not only my apples. I used to think I could control it with pruning and copper at my location, but lost almost all of my 3 yr old trees in 2017 due to FB.
I don’t know where I got the idea that repeat sprays weren’t a good idea. Alas, I probably should have done the pears last weekend.
Lois, you may have gotten the idea that repeat sprays weren’t a good idea from discussions on this forum that spoke to the issue of antibiotic resistance. And that’s a question I don’t know the answer to. I hope your pear is OK!