Dormant Oil Impact

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PSU4ME
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Dormant Oil Impact

Post by PSU4ME » May 14th, 2018, 9:33 am

So I applied dormant oil this year to the trees in early Spring.....no big deal. Leaves broke, buds got big and then they bloomed.

Then started the gypsy months so i washed out (with just water) the dormant oil sprayer, added BT and sprayed the blooming trees. Things looked fine. Then about a week later, I added a little surfactant to that same mix (it was beading a bit the first time) and sprayed the trees on Thursday. Came back from a little trip on Sunday (yesterday) and all the blooms are brown and the leaves look pretty distressed as well.

Other than the possibility of there being dormant oil left over in the sprayer, would you expect BT/surfactant to do this?

greenrebellion
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Re: Dormant Oil Impact

Post by greenrebellion » May 15th, 2018, 8:17 am

BT / Surfactant shouldn't cause an issue on flowers. I've done it numerous times.

Dormant oils will cause problems with flowers as well as phytotoxicity on leaves. But it would seem strange to me if the minimal amount of oil left in your sprayer caused an issue. I do use Citrasolve to clean out my sprayer whenever I spray oils just to be on the safe side.

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PSU4ME
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Re: Dormant Oil Impact

Post by PSU4ME » May 15th, 2018, 9:59 am

Thanks for the reply...i too am a little shocked by whats happening. I watered them heavily yesterday to wash the leaves off and of course some water for the tree. The white flowers all browned out, its so weird.

I did read that a BT mix is not supposed to set for more than a day, this one sat for 4 days between sprays so possibly something there but i'm not sure.

Hopefully with it being early in the spring things will come around. lots of rain this week too so water shouldn't be an issue!

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Re: Dormant Oil Impact

Post by Green » May 17th, 2018, 4:02 pm

I think you were the one who suggested I use molasses as a surfactant. What did you use?

I have black areas on the bark where paper bands were last year. Not sure what might cause this. It just appeared fairly recently.

I sprayed Bonide All Seasons oil on the gypsy moth eggs I couldn't reach back in March or April, before the leaves opened. I haven't sprayed Bt yet, but if it damages flowers/new leaves, I'm not sure if I should do it soon. I was going to.

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