Garden Help Desk: Solitary wasps are beneficial to your yard
A solitary wasp nest may look a little like a miniature gopher hole, but the wasps don't cause damage to our landscape plants.
Solitary wasps are mild-mannered and very beneficial because they eat many of the insects that we think of as landscape pests.
Hot summer days can cause bean blossoms to dry and drop, reducing the number of green beans you can harvest.
Question: I have this little pile of dirt with a hole in it in my yard. There were bees hanging around it. How do I get rid of them?
Answer: This hole looks like a solitary wasp nest — a lucky thing for your yard! I can’t tell you exactly which species, but solitary wasps are considered beneficial, as they prey on other insects and spiders. They’re generally docile and don’t sting unless they are directly handled.
The solitary wasps that make these holes are females. The holes are individual nests but sometimes more than one female will build a nest in the same area. They kill and collect spiders and insects to provision the nests for the egg(s) they lay in the hole.
I had a couple of these nests in my yard last year and saw one of the females hovering near a nest. The nests weren’t visible after a day or two, and I never saw any wasps again.
Because these wasps are docile and so beneficial, insecticides aren’t needed or recommended.
Question: I planted a 6-foot row of pole beans this year. The vines look good and I get lots of blossoms but the blossoms dry up and drop off, so I don’t get any beans. Am I watering too much? Not enough? I haven’t seen many bees near my beans, so maybe pollination is the problem? I’ve been growing pole beans for years and this has never happened before. What can I do to get green beans?
Answer: You have lots of company this year. We’ve had many calls and emails about pole beans that aren’t producing beans, even though there are lots of flowers on the vines. We can probably blame our hot, dry weather for this.
Every vegetable has its heat limits, and green beans seem to reach their limit when our daytime temperatures edge into the 90s. Most of our plants were blooming at about the time that this hot weather arrived, and the blossoms are pretty sensitive to heat and low humidity.
Most green bean varieties don’t need bees for pollination, so don’t worry about the number of bees around the vines.
What can you do to get green beans this summer? Avoid swings between wet and very dry soil as drought stress will make the problem worse. Deep, consistent watering makes a difference. You might also mulch the soil with an inch or so of compost to help even out the soil moisture between waterings. Even with good care and appropriate watering the blossoms can’t tolerate the hot, dry breezes and intense sun we’ve been having, but be patient, take good care of your beans and hang in there until the days cool down in a few weeks.
Question: Last month I received two small, unwanted packages from China with seeds inside. They looked like cucumber seeds. I threw them away because I saw on the internet that they might be invasive or carry diseases. Today I received another shipment, unsolicited. What should I do with them?
Answer: Many people have been getting seeds like this that they didn’t order. You shouldn’t plant these seeds; you don’t know what they really are, whether they’ve been treated with a fungicide or some similar pesticide or whether they are an invasive plant species. The Utah Department of Agriculture and Food has asked that any unsolicited seeds from oversees not be planted and they’ve requested that the seeds, along with all their packing materials, be sent to them. You can mail the seeds and packing materials to:
Utah Department of Agriculture and Food
ATTN: State Seed Lab
PO Box 146500
Salt Lake City, Utah 84114-6500
Or drop the seeds off at their offices at:
Utah Department of Agriculture and Food
ATTN: State Seed Lab
350 N. Redwood Road
Salt Lake City, Utah 84116
