NEWS for North Dakotans
Agriculture Communication, North Dakota
State University
7 Morrill Hall, Fargo, ND 58105-5665
August 6, 1998
Ron Smith, Extension Horticulturist
North Dakota State University
Q: I have an apricot tree that is beautiful, but the fruit is all wormy. What can I do to stop this problem? (Waubay, S.D.)
A: How frustrating to await the delicious fruit of the apricot only to find it wormy!
It could be any number of insects: the plum curculio, green fruitworm, apple maggot, sawfly larvae, or a beetle larvae—you name it. Anyway, the first step is sanitation. Rake up and destroy all fallen fruit. Remove any fruit remaining on the tree going into winter. Spray the tree with lime-sulfur next spring before leaf-out, then spray at full blossom with Malathion or Sevin, being careful NOT to do it when the bees are active. Spray again in 10 days. That should do it. If you should get too many apricots to eat, send some up here! I love `em!
Q: Enclosed are samples from a raspberry bush and a tomato plant. The canes with berries on them are browning and breaking down, but the rest of the canes are fine. Can you help? (Britton, S.D.)
A: Your raspberry is being attacked by a rapscallion known as the raspberry cane borer. These critters appear in the plantings in June and begin feeding on the tender cane tips, and before laying her eggs, the female punctures the stem with her mouthparts in a girdling fashion, about 6 inches from the cane tip. This is what causes the breaking off that you stated. The larvae will now burrow down the cane reaching the base by this fall, and into the crown by next summer.
To control, remove and destroy the infested portion a few inches below the wilted or darkened tip. Remove any damaged canes and crowns and burn. Spray is directed at controlling the adult beetle which is ½-inch long, black, with an orange thorax. Use Sevin at late prebloom or just before blossoms open.
The tomato does not appear to have any disease symptoms. The leaf curl is normal at this stage of growth and time of year. Frankly, I wish my tomato plants looked as good!
Q: My lily patch is being taken over by grass, and I am wondering what I can do to stop it. (Wyndmere, N.D.)
A: A product known as Poast will eliminate the grass from the lily planting. Don't till! That will only lead to more weed problems.
Q: We have six ash trees on the golf course in Selby, S.D., with this growth on them. Could you please identify the problem and tell us how to cure it? (Selby, S.D.)
A: Thank you for the beautiful example of ash rust—Puccinia sparganiodes—one of the most spectacular and destructive rust diseases on deciduous trees and shrubs. The alternate host for this rust is any number of marshy grasses.
This rust, along with other species of Puccinia, flourishes when the weather is wet, humid or foggy. Protective sprays (not curative) of Daconil 2787 (chlorothanlonil), Fore (Mancozeb) and Protect will limit the severity of this disease.
Since I am a strong believer in lime-sulfur being an effective sanitizer, I suggest spraying your ash trees with this material early next spring, before leaf-out. Then after the leaves unfold, make applications with one of the other fungicides about every two weeks, according to label instructions.
Q: The soil in my flower bed seems to be really hard. I have tried to add some peat moss and fresh dirt, but to no avail. (Jamestown, N.D.)
A: You are doing right by adding peat moss and working it in. Just go one step further and mulch with either peat or bark chips. The mulch should be 2 to 4 inches thick. You will find that after one growing season the soil will have softened considerably.
Q: I am sending you a sample of my hollyhock that has quit blooming. I also enclosed a sample of some violets that have taken over my front yard. (Jamestown, N.D.)
A: The hollyhock has a bad case of rust! Clean up the area completely this fall. Next spring apply a sulfur-based fungicide such as ferbam or maneb. Or, if not available, use Daconil 2787 as a protective spray.
If the violets are really thick and the area shady you might be better off accepting them as the ground cover. To reclaim the grass, use Trimec. It will take two or three applications to completely wipe them out.
Q: I have had this hoya plant for 32 years, but the new leaves have a funny, leathery texture. The edges are curled under on some of them. What causes this? (Venturia, N.D.)
A: It is difficult to pinpoint what could cause this problem. Here is a list of possibilities: insect damage, underwatering, poor light, potbound or low humidity.
If it has been more than a year since you've repotted, I suggest starting there.
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Source: Ron Smith (701) 231-8161
Editor: Dean Hulse (701) 231-6136