October 4, 2001

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: The enclosed plant appeared in our garden. Where it came from we don’t know. It did bloom with yellow flowers. Can you please identify the sample for me? (Butte, N.D.)

A: That nasty thing you sent is known as buffalo bur, a member of the nightshade family. This ugly relative of tomatoes and peppers is an annual that is easily controlled with herbicides (or simply pulling).

Q: Can you tell me what is wrong with my apple tree? (Hankinson, N.D.)

A: Your tree is a plant pathologist’s dream! I saw apple scab, fireblight, hail damage, and downy mildew. Your best bet is to clean up everything this fall -- leaves and apples. Then, next spring spray with dormant oil spray and lime sulfur. After the flower petals begin to drop, spray with Bordeaux mixture and repeat at least twice, in 10 to 12 days. If the tree doesn’t improve after that, then cut it down.

Q: Can you tell me how to get rid of the enclosed worms? They are all over and driving us crazy! (Java, S.D.)

A: What you have are millipedes, an arthropod that is very difficult to control once it invades the house. They like dark, damp places. I had to employ a professional pest care company (Orkin) to rid my house of them right after we moved in, 16 years ago. It worked beautifully! Haven’t seen one since!

Q: Enclosed is a leaf from my peace plant. The leaves are turning brown. Can you tell me why? I transplanted it this September and it was really root bound. I feed and water it once a week. What am I doing wrong? (Jamestown, N.D.)

A: I suspect that it is getting too much fertilizer or the container is not free-draining. The damage looks like salt burn.

Q: We have a hackberry tree. It is going on the second season since we planted it. Some of its leaves have little seed-like lesions. Is this a problem? What would you suggest we do with it? (Maddock, N.D.)

A: Nothing. The galls are known as nipple galls, caused by a mite stinging the leaf tissue in early spring as they unfold. It is nothing more than cosmetic damage.

Q: Enclosed are six leaves from my three apple trees. It appears they have a disease of some kind. My apples all developed well, but I always have another problem. I spray at least three times during the summer, yet about half the apples still have worms. We never had worms on our Bartlett pears until this year. I spray with regular fruit spray, with soap and with Malathion. someone suggested Sevin. Also, I planted a Sweet Sixteen about six years ago. This year it finally had two apples. Do they take that long to produce? (Mobridge, S.D.)

A: One of the best ways to control insect/disease problems is via good sanitation. Clean up fallen leaves and spray next spring with lime sulfur while the trees are still dormant. Yes, it does take six years to bear fruit.

Q: Enclosed find a branch from a gold mini back bush. We planted about six of these three years ago around the foundation. This year they all turned brown. Any help would be appreciated. (Wimbledon, N.D.)

A: This is a strong example of salt burn from the root system. I suggest getting the plants out of their present location ASAP and either replacing the soil completely or planting the shrubs somewhere else.

Q: I think my soil is lacking phosphorus. What is the best natural (organic) or otherwise phosphorus to use? When do I apply it? Also, where do you recommend sending a soil sample for testing? (Bonney Lake, Wash.)

A: Rock phosphate is the natural source. Superphosphate is treated with sulfuric acid to make the phosphorus more readily available. It is best applied into the soil in the fall, to give it time to become available the following spring. Work it into the upper 6 inches, using about 40 pounds per 1000 square feet. For soil testing, your best bet is to contact your local state university, requesting their soil test lab. The price for a fairly complete soil test (N, P, K, pH, soluble salts, Ca, Mg) is usually between $20 and $30.

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. Note to e-mail correspondents: please identify your location (city and state) for most accurate recommendations.

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Source: Ron Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Gary Moran, (701) 231-7865, gmoran@ndsuext.nodak.edu