NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665
September 16, 1999
Ron Smith, Extension Horticulturist
North Dakota State University
Q: I am finding slugs around my house that are about 1.5 inches long with a sharp tail and two small antennas in the front. They are flesh colored and leave a trail of slime behind them. I used two cans of diazinon and sprinkled around on the areas of the lawn where I saw them and also sprayed tempo on the ones on the deck that I could see. Please help me get rid of them, since nothing I have tried has helped! (Washburn, N.D., e-mail)
A: On such a grand scale as yours, you have a problem that is beyond any attempts a homeowner can make to correct. They will drown in water and beer, can be controlled with sharp sand and hydrated lime and poisoned with methaldehyde, but in your case I suggest a professional exterminator to do the job, if you can get one.
The products you mentioned are insecticides and are ineffective against mollusks, which slugs are. So, do not employ those products any more because you are wasting your time and money, and causing a disruption of the ecosystem--which the slugs are also causing.
The natural predators--snakes, frogs, birds etc.--apparently are not doing their job, or are overwhelmed by the smorgasbord before them! To keep them from getting into your home, try spreading diatomateous earth in front of your doorways. That stops them cold.
Q: I need to plant one more shade tree in my back yard hoping it will eventually shade our patio. I have an Autumn Blaze maple nearby which has done beautifully. Can you suggest another tree that would grow relatively fast, but also a nice compliment to the maple? (Barney, N.D., e-mail)
A: If you like the Autumn Blaze, why not go with another? The only thing better than a single beauty are two of them! Silver Queen (another silver maple) could also be used, but I like the Autumn Blaze better. If you want more of a patio tree--getting to about 20 to 25 feet tall--the Amur Maple cultivars are fantastic for that purpose. Whatever you do, stay away from the poplars!
Q: Can you tell me what weed is growing in my lawn? In the summer it matches the grass pretty well and now it looks dark and goes to seed. How can I stop it besides killing the whole lawn with Roundup. (e-mail)
A: The weed is crabgrass, an annual that is easily controlled with pre-emergent herbicides in the spring around the time lilacs bloom.
Q: We have a fairly large patch of strawberries, but have been getting few berries out of this patch. What type of fertilizer should we be using and how often? Also, what should we use for weed control? We also have a large patch of raspberries along the south side of our garage and we've always gotten quite a lot from them except this year. Is it possible that this patch is dying out? It is more than 10 years old and, we have never done anything with it except to cut out the dead canes. (Barnesville, Minn.)
A: Your strawberries may very likely have a virus disease, one of the symptoms of which is a yield reduction. They and the raspberries should be fertilized twice a year; once in the spring at initial growth or green-up, and again right after harvest. The material to use is 5-10-5 at about 10 to 15 pounds per 100 square feet.
Raspberries just don't "die out" unless something is killing them. It be virus, root rot, cane cankers, anthracnose, cane borers etc.
Both crops require constant attention to good management practices to be sustained productively. For example, the old mother strawberry plant should be tilled up each year, allowing the daughter plants to be more productive. The following year, those daughters are tilled and so forth.
Q: We've just harvested out potatoes and have a very small yield. The plants had a blight and died prematurely. What can we do to have better results next year? We planted three varieties, and the Red Norland were best. Are some kinds more resistant? Is there a spray that will control the disease? (Tappen, N.D.)
A: Potatoes are best grown on land that is part of at least a 3- to 4-year rotation: beans, cabbage, corn, potatoes etc. There are resistant varieties or cultivars to consider as well, and Red Norland is one of them. Others are Goldrush, Katahidin, Kennebec, Red Pontiac, Russet Norkotah and Superior.
Concerning sprays, I cannot advise you unless I know what did the killing. There is verticillium, fusarium, several potato viruses, black leg, scab, early blight and late blight. Using resistant varieties is the best approach. Red Norland and Kennebec (white) offer the broadest range of disease resistance.
Q: I have a case of fireblight in my cotoneaster hedge. We've been cutting out the diseased parts with a trimmer and sterilizing it before each cut. Will this get rid of the disease? Or, do I have to cut it completely back to 4 inches and spray it with something? I hate to start over when it has reached the height and fullness I desired, but it is 20 years old and I'm not sure what their longevity is. (Kulm, N.D., e-mail)
A: You are doing the correct thing, cutting the hedge back, about 12 inches below the fireblight canker. I recommend a heavy cut back only when the disease is completely debilitating to the hedge. You should also be applying an antibiotic to the hedge--streptomycin, or a fungicide containing basic copper sulfate--next spring prior to bud break. Continue to spray at intervals of five to seven days until bloom is completed. During the summer prune out immediately any diseased shoots that show up. Don't fertilize! This only encourages lush growth that is susceptible to the bacterium. If you fertilize your lawn adjacent to your hedge, give yourself a clearing of about 10 feet with no fertilizer going down. Cotoneaster are one of the more susceptible species to this disease, so it will require careful monitoring and management on you part.
Q: My oak tree is showing symptoms of stress with the leaves browning and dying at the ends of the branches that have worm tunnels. There are several trees in the community showing this stress condition. (Fergus Falls, Minn.)
A: Judging by the size of the boring hole, the culprit appears to be the carpenterworm. The grub stage is the destructive phase in the life cycle. The adult is a moth. If possible, cut back the branches infested with the borer and burn. This will require the services of a professional arborist because of the size of the trees. Next, spray the trees with methoxychlor or chlorpyrifos in spring and summer. Do all you can to maintain tree health and vigor--fertilize, water, prune etc. Once begun, borers are not easily controlled!
Q: The leaves from our two Patmore ash trees are curled, and it appears to be herbicide damage. An Amur maple about 20 feet from the two ash trees has similar characteristics. The only reason I question herbicide damage is that there is a spirea and a Virginia creeper within 10 feet that are perfectly healthy. Any thoughts? (Pierre, S.D.)
A: The symptoms suggest phenoxy herbicide damage. The fact that the Virginia creeper is so close by and unaffected could indicate that the herbicide--whatever it is--is migrating via ground water to the root system. Or, it could be that when the herbicide was applied and the drift occurred, the Virginia creeper was not yet in leaf.
Q: My garden is full of blight, the tomatoes have just the vines left, no leaves. Is there anything I can put on the garden this fall to prevent blight next season? (Jamestown, N.D.)
A: There are a number of steps you can take to help assure that your tomatoes will not be as blighted again:
- Clean up all plant debris this fall, and if time permits, turn over the garden soil.
- Select only those resistant tomato cultivars next season. Look for the letters V, F, N behind the names, which indicate Verticillium, Fusarium and nematode resistance.
- Stake or cage your tomato plants next year. They typically are healthier, and produce better, along with having fewer disease problems.
- Avoid overhead watering or splashing water on tomato foliage. This contributes to more disease problems than most people realize.
- Mulch the plants with compost or sphagnum peat moss. This will modulate temperature and moisture extremes, and prevent or greatly reduce rain splash.
Q: I saw a tree growing in Lexington, Ky. The pods were about a foot long. Can you tell me what it is and if it will survive in Minnesota? (Osage, Minn.)
A: The tree is a honey locust tree--Gleditsia triacanthos inermis. And yes, it certainly should grow in your area of Minnesota since they grow up here in Fargo! They make a very attractive shade tree, providing dappled shade/sun under its canopy and thus allowing most species of turfgrass to thrive.
Q: Can you please tell me how to get rid of a weed in my lawn? I've had three applications of Weed-B-Gone and it hasn't even touched it. (McLaughlin, S.D.)
A: No wonder. Your weed is ground ivy, one of the toughest to control. Switch to Trimec, which is potent enough to kill off this persistent pest.
Q: I raised some bird house gourds this year and believe it or not, there are some 12-inch gourds coming! Now I don't know what to do next! Should they be left on the vine until it freezes? Would I hang them in a cool, dry place to cure and how long will that take? (Fessenden, N.D., e-mail)
A: Yes, allow them to stay on the vine until our first frost. Then harvest and drill a small hole in the blossom end to allow air in. Hang in a cool, dry location until you hear the seed inside rattle. Then you can cut, paint or do whatever to your heart's content!
Q: The fern peonies here in town have now begun to brown and fall down. Can they be cut to the ground yet? I know the leaves of dandelions that currently are growing freeze over the winter, but do new shoots come from the existing plant next spring? In other words, is it of value to spray and kill the current plants to ward off them reappearing again in the spring? I have red twig dogwoods that have exploded out of control this summer. Beautiful, but drooping with new growth making for difficulty mowing under them. How does one deal with such ambitious growth? It seems to me that certain oaks at the farm produce way more acorns than other oaks of the same size. I think that there are some oaks that produce no acorns, but I could be wrong about that. Any thoughts on this? (Fertile, Minn., e-mail)
A: Cut down your peonies. Spray your dandelions. As for dealing with your dogwoods, the best method is to cut them back to make mowing easier. Not to worry, they are completely winter hardy and will not suffer from a late summer pruning. The other way, tying them up, is a band-aid approach and not very effective or pretty.
And, it is true that some oak trees are more fruitful than others. Sometimes the fruiting is related to the stress the trees are under, as well as the age. Older, stressed trees will tend to fruit heavier, while younger (but still mature enough) less stressed trees will go fruitless or bear very little fruit. Another reason could be hardiness. The flower bud is less hardy than the leaf bud. Hence, the oak that is marginal in hardiness may get caught in a late spring freeze that kills the flower bud, but doesn't harm the leaf bud.
Q: The local cemetery has grubs in it and the racoons and skunks dig for them and are damaging the grass. What can we use to get rid of the grubs? (Wheaton, N.D.)
A: Grubs can be controlled by using Sevin or diazinon. Apply now, and water in. Repeat next spring when the grass has begun active growth.
Q: I am having problems with slugs eating my tomatoes and potato bugs eating the potato leaves. Is there any way to treat the soil in the fall or spring to keep this from happening next year? (Fosston, Minn.)
A: There is a product called "Slug-Getta" that is an attractive poison. You can also get slug traps from garden centers or make them yourself. To make one, push a shallow dish into the ground and fill it with beer. The slugs will be attracted to the smell, fall in and drown. Potato bugs can be controlled by using a resistant variety, or by following a strict spray program. Clean all garden litter up this fall, turn the soil over to expose the pests and have our winter help in killing them. Also, hope for a drier summer next year.
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Do you have a gardening or houseplant question? Write to Hortiscope, Box 5051, NDSU Extension Service, Fargo, ND 58105 or e-mail to Ron Smith at ronsmith@ndsuext.nodak.edu .
Source: Ron Smith (701) 231-8161
ronsmith@ndsuext.nodak.edu
Editor: Dean Hulse (701) 231-6136