Quite often I get interesting questions about gardening that aren’t related directly to planting by the phases of the moon and signs of the zodiac.
If I can, I try to do a little research and answer them myself without disturbing the experts at the Extension Office and elsewhere if at all possible but since we Master Gardeners were told in our classes to refer all herbicide and insecticide questions to the professionals, I didn’t take a shot at Marsha’s question and I had no idea how to answer David’s.
So I turned to local experts at the University of Kentucky Cooperative Extension Service and the manager of Southern States Cooperative. The local experts went one more step up the ladder to research experts in the University of Kentucky’s Department of Agriculture while the Southern States manager offered another option when I called him to see if he had one of the products UK had recommended.
What about those worms?
A couple of weeks ago before it started raining again, David wrote:
Mr. Case:
“This is not an official Letter to the Editor.
“I am just curious and I do not know who else to ask.
“Why have all these thousands of worms crawled out of the ground recently and died on the asphalt and concrete driveways, sidewalks, and roads?
“This is a serious question.
“In my neighborhood, in the last 10 days, many thousands of worms have left their dirt and crawled onto the pavement and died there.
“I know the worms do this when they are flooded by rain. But it has not rained. It has been hot and dry. So why did they do this? Do you suppose it is because of the early summer heat?
“Is this an ordinary yearly event? If so, I do not remember it happening in 2010, 2009, or 2008.
“I am neither a farmer nor a gardener, so I have no investment in this massive worm die off. But I am curious.”
And here’s the response from UK:
Q. Why do large numbers of earthworms come to the surface?
Occasionally, large numbers of earthworms are found dead on sidewalks and driveways. What happened? Why are they there? No one knows for sure but there are several potential explanations.
Migration is at the top of the list. Earthworms can travel more efficiently on the surface than they can down in the soil. But, they breathe through their cuticle (skin) which must be moist.
Normally, the ground surface and air are too dry to allow them to remain exposed for very long so movement must be through the soil. Moisture and humidity from rain allows them to remain up longer and move further than possible under drier conditions. Also, it is easier to burrow back into the soil when necessary.
At one time, it was thought that earthworms had to come to the surface after rainy periods to keep from drowning in saturated soil. This does not appear to be the case.
Other explanations for earthworm surfacings include: a sensitivity to low soil pH which could be the result of heavy applications of nitrogen to the turf; reproduction – however, only a few species come to the surface to mate; vibration – earthworms will move to the surface in response to vibrations, including that from rainfall; application of lawn chemicals – earthworms come up where no chemicals have been applied.
Earthworms are legless so they move by wriggling their body. Very small bristles spaced along their body provide some traction that allows them to move through the soil and though the grass pretty efficiently without having legs to get in the way. The system doesn’t work on surfaces like concrete or blacktop so the worms are stranded in the hot sun and dry air which quickly kills them.
Killing a wild grapevine
Marsha shares her dilemma:
“Just wondering if you can tell me how to kill a wild grapevine. I cut them completely back last year and it came back this year. It would be hard to dig it up because it is in a fence row.
My grandmother's lilac bush is planted about 5 feet from the root of the grapevine. I am afraid it is going to over take the lilac. Please let me know if you have any suggestions. My grandmother has been gone for 17 years and my lilac bush is one of my favorite thing ever!”
From UK:
“Cutting down the vine and IMMEDIATELY painting the stump with Crossbow, a powerful herbicide (if a homeowner can get it) or Roundup (particularly the Poison Ivy/Brush formulation) would do the trick. And then to touch up with painting any new shoots that might emerge.”
It was the concern about whether or not a homeowner can purchase Crossbow that prompted me to call the Southern States manager.
He said they did indeed have Crossbow for the homeowner at Southern States, adding he would recommend Tordon RTU (Ready to Use) also for what he called an application to a "fresh-cut basal stump," which is what Marsha will have when the grapevine is cut.
He said this is a spray-on specifically for this purpose and it will do the job immediately. He said Crossbow will, too, and the only advantage to that is you can use Crossbow for other label-okayed purposes, too, while the Tordon is, again, specific for stumps
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