well, this is a new one for me. Looked at the underside of some branches on several maples and found a nasty surprise. The branches looked they have been filleted from the underside. Brittle even though leaves look fine. Definitely going to be some big time dieback and probably some lost. I assume this is some sort of sunscorch as we are in the midst of a nasty heatwave and the worst damage is in areas that receive the most afternoon sun (but actually little wind). The things that surprises me are: 1) the damage is on the underside, not the sun exposed side 2) We have hot summers every year here in st. louis, but this is the first I have seen of this (although I have only grown JMs for 4 years) 3) little leaf burn Any thoughts? Suggestions?
Unusual. I wonder if it could be Cicada damage? Did you have a large outbreak this year? I know they slit the bark on tender branches and lay their eggs inside.
that's it!! We did have a bad outbreak this year: http://www.kplr11.com/news/kplr-cicada-swarm-st-louis-summer-051811,0,7710460.story The damage is identical: http://www.google.com/imgres?imgurl...page=1&ndsp=33&ved=1t:429,r:0,s:0&tx=86&ty=62 http://aviatrixkim.wordpress.com/2011/06/01/cicadas-do-their-worst/ The latter post is JM specific. This actually very good news to me - I can deal with this once every 13 years. Should I just cut off all affexcted branches now ? thanks a lot
Not sure how to kill them. The eggs hatch underneath the bark and then the young grubs fall to the ground and burrow down for 13 years of feeding. I guess it would depend on which stage they are at if you can kill them or not.
Nope, sorry, I was not clear. The cicadas are long gone (this is why I didn't initially put two and two together) and I suspect the nymphs already in ground. I was thinking of cutting of the branches not in an attempt kill the cicadas, but with the understanding that these branches would only die anyway and would like to avoid any secondary infection. I don't suppose anyone would recommend trying to treat the nymphs in ground (My gut tells me that would just be inviting trouble)?
Evidently, once they get down to the tree roots there doesn't appear to be much you can do.. Controlling Cicada Adults and Nymphs The best treatment for cicada damage is prevention. If your fruit trees are at risk, treating the bark with a liquid pesticide safe for food-producing trees can kill adult cicadas before they lay eggs. Reapply every 1-2 weeks, depending upon the pesticide used, and possibly more often in rainy weather. Try to treat only the young trees most at risk. Larger trees may see branch flagging due to cicada damage, but are unlikely to suffer severely. When cicada nymphs emerge from eggs and are ready to begin feeding on tree roots, they fall from their egg slits to the ground and burrow into soil. To prevent them from damaging roots and reducing growth rate, apply a pesticide labeled for cicadas in granule form to the soil surrounding any tree with egg slits or shed cicada skins on the trunk or branches. Before cicada nymphs reach your tree’s roots, they’ll contact the treated dirt and perish.
