Neem oil in fruit orchard
(Westfield NC USA)
I have a small orchard of 17 fruit trees. This year I couldn't find the spray I would usually use, which was a blend of Malathion, which kills spider mites, aphids, and similar insects and arachnids, Carbaryl, a general insecticide, and Captan, a fungicide.
Instead I used a fruit tree spray of which the main ingredient was Neem oil, with which I was not familiar.
I had my suspicions when the label said to apply the spray at the first sign of insect damage. As any orchardist knows, to have clean fruit you must begin spraying long before that -- when damage is first evident it is too late; the insects have already pierced your immature fruit and laid their eggs inside.
So I used it as I would the other spray, before blossoms opened, at petal drop, and about every 2 weeks afterwards. As usual, I could not spray as often as I should, because weather conditions, etc. always conspire to interfere. But the first few sprays are the most important, and I did get those right.
My peach and plum trees were loaded this year. But I was very disappointed when the peaches began to ripen, as virtually all of them were infested with worms, I suppose curculios (a type of weevil). Brown rot also claimed very many of the ripening peaches, as I don't think the spray contained any fungicide (I threw away the empty bottle so I'll have to check that the next time I'm in the store).
What I know is that the wastage was truly awful, and there was hardly a perfect peach in the lot. The plums were so heavily infected with brown rot that we hardly got any to eat, and what we did get was mostly picked and eaten slightly green, not full-flavored because it wasn't ripe enough. They rotted before they could ripen fully.
I am never going to depend on Neem oil products again; they may be environmentally better but they don't do the job. Our local hardware, where I bought the stuff, is carrying fewer and fewer of the effective pesticides and more and more Politically Correct "green" insecticides that are so safe they wouldn't hurt a fly. I have located another source for the fruit tree spray I used to use, and will be buying it there in the future.