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leaves on new growth curling under, turning brown

Posted by Peter Drevniok 
leaves on new growth curling under, turning brown
July 19, 2017 01:03AM
Hi,

I am not sure if this query should be in bug-by-bug or fungal pathogens:
on the majority of my trees (third year) a lot of the leaves are curling down from the tip back to the stem.
The tip and sides of the leaves are turning brown and are crisp to the touch.
I see no evidence of any type of catepillar or curling midges (not saying they are not there however).
There are some lime green aphids but not a lot and I see no eggs or farming ants about.
Any ideas as to what might be the cause? Thanks

Peter Drevniok,
zone 4b, Wakefield, Quebec
Re: leaves on new growth curling under, turning brown
July 19, 2017 01:10PM
Peter-
I would make sure that the "lime green aphids" you are seeing are not Potato Leafhopper,(PLH) whose toxic saliva causes just the type of curling and burning effect you describe. The PLH will jump sideways or scurry down the stalk when discovered, and are much more mobile than an aphid.
Re: leaves on new growth curling under, turning brown
July 19, 2017 02:50PM
This has been a horrible year for PLH on all farms that I check. Its been the predominance of southern storms that bring them up. And not matter how many times you kill them, they keep coming in.

Mike Biltonen, Know Your Roots
Zone 5b in New York
Re: leaves on new growth curling under, turning brown
July 19, 2017 04:04PM
I'm seeing quite a bit of damage to foliage over the last several weeks that I had independently suspected was PLH, probably in combination with aphid damage. What is the prognosis for a young orchard being swarmed by these critters and what can / should be done about it?

My default response since I planted last year has been "strategic patience" - try not to panic, just observe what is happening and learn what the orchard can bear on its own. The one intervention I used last year was tanglefoot, which quickly allowed the ecosystem to cleanse itself of a bad aphid infestation. However, even with surveyors tape wrapped around the trunks, the tanglefoot seeped through and penetrated the bark, which concerned me. So I didn't use it this year. I wonder whether allowing the ants to roam free has prevented the beneficial from not only attacking the aphids, but the leafhoppers as well.
Re: leaves on new growth curling under, turning brown
July 20, 2017 12:23AM
Thanks Jason et als,

Indeed, it seems to be PLH and the ones (two of them) I looked closely at are in the nymph stage.
Now what to do. Will an insecticidal soap spray be effective or should I spray a 0.5 % neem solution perhaps with a garlic scape
tea additive. Any suggstions are greatly appreciated.

Peter Drevniok,
zone 4b, Wakefield, Quebec
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