I've heard about several sections of freeway north of me(in an area I don't get to too often) where the robinia mostly on the north slope have died out. from a distance he said it looks like some one girdled them. too far away for salt. adjacent trees ok....

This is just a curiosity, I saw some cable trenching in the area some time ago so I figure it's probibly from that. hvern't noticed it anywhere myself.

I was asked to poke around and see if anyone has heard of anythig that would kill a black locust quickly. dead leaves persist.

BTW i'm in s/e WI.

Reply to post by JPS , on August 18, 1999 at 22:11:47:

What area are you in? Robinia around here suffer terribly from leaf and plant hoppers, sometimes webworm thrown in to boot. They can leave the leaves and whole tree looking dead- but the come back the next spring. Find out if it includes twig dieback or just foliar necrosis.

Reply to post by Russ Carlson, on August 18, 1999 at 22:11:47:

Here in metro NY with the extended drought we're seeing trees of various species going brown along the interstates and other highways where they have grown up on rock cuts or were existing on rocky hillsides and ridges which are clearly visible from the highways. Haven't noticed Robinia partcularly.

We don't see much of the sucking insect damage on Robina and only occassionally webworm.

Reply to post by Scott Cullen, on August 18, 1999 at 23:29:53:

Down here we can count on stands of black locust to turn brown. Not every tree- usually in denser pockets, and the occasional isolated individual.

Road side trees- well that could be the drought this year.

Reply to post by Russ Carlson, on August 19, 1999 at 21:13:44:

Our black locusts often look dead by August due to leaf miner damage, but they always come back. This pest seems to cycle... or they have good and bad years. So a locust can look great one year and dead the next.
It's downright tough to kill a black locust!

Reply to post by Russ Carlson, on August 18, 1999 at 22:11:47:

Milwaukee Metro area in south east WI.

I'm going to have to find time to look at them I guesse, he got me curiouse.

Drought hasn't been bad here, we've got almost 4in this month. A little short but only the biggest trees in the smallest lots are dropping leaves. And dew has been real heavy almost everyday.

Fall webworm isn't active...yet. Maybe a week or two.

Thanks all.

Reply to post by JPS , on August 18, 1999 at 22:11:47:

Did about 80 miles on on two interstates and two parkways in Westchster (NY) and Fairfield (CT) Counties today. The Robinia generally looked good. A VERY few on extremely rocky ridges showed a very little browning. A few more showed a scattering of yellow leaves... early senescence not scorch.

So Robina seems to be quite drought tolerant. And in this neck of the woods there seem to be no severe sucking insect infestations on Robinia.

As an aside most of the severe drought effects seemed to be on red maples and oaks, scorched, based on distant canopy profiles. These on rocky ridges. Also birches. Liriodendron were nearly defoliated in some instances.

Reply to post by Scott, on August 18, 1999 at 22:11:47:

Keep your eyes on the road, son!

Damn yankee drivers.....

Reply to post by The fuzz, on August 23, 1999 at 22:13:59:

Drove by them yesterday and at 65mph (or so) they looked like they were sprayed with something.

Couldn't stop to look close 'cause this new International we got is a sow on the take off, tho I need about 8yrds of chip in it to notice.

Reply to post by JPS , on August 18, 1999 at 22:11:47:

Investigate for locust borer (Megacyllene robiniae). Especially if there be breakage of trunks, branches, or knotty swellings on same or the usual signs or symptoms of borers.