Questions on: Nightcrawlers

Ron Smith, Horticulturist, NDSU Extension Service

Q: Everything I read is so contradictory. Are nightcrawlers a good thing to have in a healthy lawn? I have found a few dead spots in my lawn lately and wonder if the problem is caused by nightcrawlers. (e-mail reference)

A: Like most things in life, having some nightcrawlers is a good thing, but having too many can cause mowing and even walking problems. Dead spots in your lawn can be caused by beetle grubs, dog urine, ice encasement during winter, fertilizer spill or overapplication and any number of diseases.

Q: I recently moved into a house in West Fargo. The night crawlers are bad. I have read about using Sevin, but I’m wondering if it is pet safe. Also, can you suggest a fertilizer that is pet safe? What is the best time of year to fertilize and use Sevin? (e-mail reference)

A: My best advice is to contract with a licensed lawn care operator to take care of the problem. The lawn care service has the equipment and know-how, and will do a much better job than either of us could. Once watered in, there is nothing to worry about. Scotts Turf Builder, or one of its generic copies, is an example of a good fertilizer.

Q: I am writing regarding your Internet article on the control of nightcrawlers. I have a method of controlling nightcrawlers without the use of pesticides. Pour a bucket of soapy water on the infested area. Liquid dishwashing soap works fine. In a few minutes, the crawlers will come up to the surface for air. Pick up the worms and place them in a small bucket. (A small boy is a great help in catching those soapy, slithery worms.) Add a handful of moist dirt. Take the bucket and a cane pole to the nearest bayou or creek and go fishing! When I was growing up on a south Louisiana bayou, this was the preferred method for controlling the local worm population. (e-mail reference)

A: Sounds like a good idea! Thanks for the tip, which I'm sure many of the readers will use next spring.

Q: Much as I like fishing and acknowledge the necessity of nightcrawlers for that purpose, I have just discovered that I have them in my lawn. Do you have any tips for eradicating these pests? (Turtle Lake, N.D.)

A: Treat your lawn for grubs. In doing so, you will reduce the nightcrawler population by about 30 percent.

Q: I have a nice green lawn, but walking on it is like walking on a field of rocks. I've been told this is the work of night crawlers. Is there anything or any way to eliminate this problem? One suggestion was to aerate the lawn. Is that a remedy? (Cooperstown, N.D.)

A: Night crawlers are nature's roto tillers. They mix the thatch and subsoil as they do their burrowing. This is good for the turf but hard on the people who walk on it or try to mow it. Core aeration, power raking or rolling with a ballast roller will help but not eliminate the problem. There is no chemical registered for their control. It has been observed that where lawn care operators use a four step program of fertilizer, herbicide and insecticide on a regular basis, populations are much lower.

Q: I would like information on how to get rid of night crawlers in a lawn. (Jamestown, N.D.)

A: Nightcrawlers can cause walking discomfort when their population is high in the spring and fall. There are no approved chemicals for nightcrawler control, although some fertilizers, as well as pesticides (to control weeds, insects and diseases) have been known to have an impact on their populations. Taking good care of your turfgrass will minimize nightcrawler problems. This involves core aerating, power raking and at least two fertilizer applications per year. The fertilizer should be applied in mid-spring and late summer.

Q: How do I get rid of the nightcrawlers in my yard? Also, should the last cutting of the grass in the fall be long or short? (Wing, N.D.)

A: Treat your lawn like it has an infestation of grubs. Simply follow directions or the bag of Sevin for grub control. It will then take care of about one third of the nightcrawler population. Cut the grass about an inch shorter with the last mowing.

Q: Do you have any solutions for night crawlers? Any advice for the white scale on evergreen trees? My wife is organically inclined when it comes to battling pests, but she will do whatever it takes to get results with these. (E-mail reference, Valley City, N.D.)

A: If the night crawlers are a big problem, I suggest applying a grub insecticide (everybody's lawn has grubs!) like Sevin. This will also control night crawlers. Be sure to follow label directions. Scale insects on evergreens is a touchy one. If they are on just a branch or two, you might be better off cutting those off now and disposing of them. Insecticidal soap can be used if you can catch them in the crawler stage in late May or early June. In the dormant stage of growth, try a horticultural oil spray (sometimes called dormant oil spray). This will kill the overwintering adults and perhaps control the outbreak further. Try your best to grow the evergreen in as vigorous and healthy manner as possible to discourage scale development. They usually attack plants that are in a weakened state.

Q. Our neighborhood is being overrun with nightcrawlers. What can be done to get rid of them? (Minot, N.D.)

A. Nightcrawlers are troublesome at this time of year, especially with all the rain this spring.

A couple of methods can be employed:

  1. If you want to wipe them out, applications of Sevin or diazinon, following directions for grub control, would do the trick. Then simply use a ballast roller to flatten out the lumps.
  2. If you want to keep the worms around for soil aeration but don't want the pilings that go along with them, simply knock them down with a power rake before Memorial Day.

Q. Can you please tell me how to control night crawlers? They are ruining my lawn and I want to get rid of them. (Napoleon, N.D.)

A. Use Sevin at the label rate for grub control. Be sure to water in well, with about 1/3 inch to ½ inch of irrigation. Repeat again in the spring when they are again active. These two treatments should give about 70 percent control.

Q. We have always had many angleworms in our garden and soil, but it has never been a problem. However, now we have found night crawlers and they are destroying an area of about 25 feet by 40 feet. Last fall I tried drowning them out by laying the garden hose on them and caught about 100 in an hour. There were also many tiny ones, indicating they had reproduced.

I pulled a lawn roller across this area to squash down the bumps. I started watering the lawn yesterday and today there must be 200 new hills again. Is there any type of chemical that will work. The mixture, the amount, how is it applied and is it to be watered—I need your advice soon.

The first thing I read every Saturday is your column. I would not ever miss reading your informative information. (Napoleon, N.D.)

A. Thank you for being such a faithful reader of the column.

The earthworm or the flat-tailed night crawler (Lumbricus terrestris) play a very important ecological role: they aerate the soil and recycle organic matter. They thrive in most soil and are most active in spring and fall.

While nothing is labeled for night crawlers, you can apply Sevin 10G at a rate of 1.9 pounds of granules per 1,000 square feet to control the white grubs your lawn has and you will eliminate about one-third to one-half of the population.

Make the application in late April or early May, and the turf should be watered thoroughly to get the chemical into the soil. Be sure to read the complete label of this and any other pesticide before using.

Follow up with a rolling to flatten out the mounds their excavations have created. Repeat application in the fall if their presence is reasserted to intolerable levels. Good luck!

Q. Can you tell me if there is any chemical spray that can be used to control Creeping Charlie that will not kill the lawn? Also control of night crawlers.

I enjoy your column and learning many things. Thank you. (Lake Park, Minn.)

A. A relatively new product for homeowners is Confront. It will control just about any broadleaf weed.

Night crawlers are controlled with an application of Sevin to control grubs. Follow label directions for grub control and about one-third of the night crawler population will also be controlled.

Refer to the enclosed circular, H-1009, "Weed Control in North Dakota Lawns," available to other readers by calling (701) 231-7882.

Q. We have spots in our lawn created by night crawlers beneath the surface. This worm will surface at night and leaves many bumps on the lawn. I have sprayed with 5 percent granular diazinon and it has not eliminated the problem.

What do you recommend to rid the lawn of this pest? (Napoleon, N.D.)

A. Apply the insecticide Sevin at label rates for grub control. Do it a couple of times and you should see a 50 percent reduction in population.

Also, rolling the lawn will level out the lumps of soil they leave behind.

Q. Some time ago you had a remedy to get rid of night crawlers, but I lost your article. Could you please send me the remedy. (Napoleon, N.D.)

A. This is a popular request at this time of year. There are several approaches to bringing them under control, which vary in effectiveness.

Let's start with the simple and work toward the more drastic treatments.

1. Core-aerate and power-rake, then roll your lawn with a ballast roller filled one-third full with water. This dries the soil and compresses some of the channels (macropores) made by the crawlers. It may limit their population to a tolerable level.
2. Apply Sevin or Diazinon, following label directions for grub control. This will control the grub population and,incidentally, about one-third of the crawler population as well.

Keep in mind that the drier you can keep your soil, the less desirable an environment it will be for night awler activity.

Q: We have nightcrawlers so prolific in our yard that we can barely walk across the grass without tripping. The lumps in the grass are everywhere. Is there anything
we can do to get rid of the them? (e-mail)

A: First of all, I suggest renting a power rake and knocking down the mounds their activity has created. Then, apply Sevin at the label rate to control
slugs. This will reduce their population by about one-third to 40 percent. If the problem persists, make a second application. By the way, nightcrawlers'
activity is reduced significantly when we get into the hotter summer months.

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