Q: I saw a wilted raspberry cane yesterday, looked closer and it appears the wilted raspberry cane tips are due to the raspberry cane borer. I’m curious if anyone else in the region is finding the same wilted cane symptoms? — Jim Walla, Fargo.
A: Thanks, Jim, for alerting us to the presence of raspberry cane borer in our region. Jim Walla is a retired North Dakota State University plant pathologist and now operates Northern Tree Specialties, a tree consulting and specialty fruit production business. Jim provides more information about the raspberry cane borer:
“Although I didn’t see any, the adult beetle is black with an orange thorax and long antennae. It girdles the new raspberry cane in two visible rings about six inches below the growing point and deposits an egg in the section of cane between the rings. The cane tip then wilts. The egg hatches and the larva feeds in that section between the rings. Later in the season, it feeds its way down the inside of the cane toward the base. The next year, it enters the root crown at the base of the plant and feeds there for one year. Adults emerge the next year of their two-year life cycle to start the process over again.
"Raspberry cane borer can seriously reduce berry production. Control by locating tips that are wilted and prune the cane off a few inches below the girdling rings, collecting and destroying the prunings. The tips break off easily, but you still need to prune below the rings so the section with the larva is removed. There are insecticide treatments, but if this can be controlled by pruning, that’s best.”
Q: Do you have any advice for trying to grow peaches in central North Dakota?
A: Peaches are classified as stone fruits, closely related to plums, cherries and apricots, but they love warmth more than their relatives do. They are admittedly a challenge to grow in North Dakota and Minnesota.
My great-uncle, wanting to prove it could be done, years ago planted a peach tree here in North Dakota, and completely surrounded it top-to-bottom with straw bales each winter. It bore peaches, but the few fruit hardly made the extensive winter protection worthwhile.
There are a few homeowners who have reported some success with peaches. First, choose one of the more winter-hardy cultivars, like Reliance, Contender or Intrepid. Peaches are self-fruitful, so you only need one for fruit production. Next, plant the peach tree in a microclimate, a sheltered spot in an established yard that is well protected from winter winds and catches generous, insulating snowfall. There is future hope on the peach horizon, as individuals are working on cultivars with increased winter-hardiness.
Q: How do I stop the spread of lily-of-the-valley? They are taking over my flower bed. — Dianne Nechiporenko, West Fargo.
A: It can be controlled with glyphosate (Roundup) applied cautiously to only the areas you wish to kill, or digging. Smothering can also work quite well in perennial flower beds to kill the invader. After cutting off the lily-of-the-valley’s foliage, lay down newspaper (about 10-20 sheets thick) between, and cover with a coating of shredded bark or even dried grass clippings. The newspaper gradually disintegrates into the soil, and in the meantime smothers what's below.
If you have a gardening or lawn care question, email Don Kinzler, NDSU Extension-Cass County, at firstname.lastname@example.org or call 701-241-5707. Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.