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Hortiscope: Use hanging wasp traps if you can't find nests

Q: In your column, I saw a letter about hornets or wasps eating honeycrisp apples. You suggested getting an exterminator, but I don't know where the nest is. They've come every year and decimated the apples on the tree. Any suggestions other than sugar water in plastic bottles?

A: Your best defense against these stinging pests is to get traps that can be hung in your tree. The wasps or yellow jackets (likely culprits) are attracted to the aroma coming from the trap.

They go in the traps and cannot get out. It is "sweet revenge" for all the stinging they have done. It will not stop them completely this late in the season, but it will reduce the problem. Next year, put the traps out about a month earlier. Set two to four traps per tree, depending on the size. This will get them started earlier and bring down the population substantially.

If you can locate the nest (usually in the ground), you can have an exterminator take care of the problem in a matter of seconds.

Q: I just planted a lawn two weeks ago. So far, everything is coming up well. When should I fertilize for the first time? Keep in mind that I did not put a starter fertilizer down. I have a 60 percent blue grass and 40 percent rye and fescue mixture.

Is this something that should wait or is it OK to put a little fertilizer down? I have a 60,000-square-foot yard.

A: You can fertilize after you have mowed the grass at least two to three times. You can fertilize in the middle of October unless you live where you'd be covered with snow or the soil is frozen. Fertilizing will benefit the grass this fall and next spring. An acre and a half of grass is a lot to mow and fertilize! While I'm all for a grassy landscape for beauty and play, the mowing of that much grass is no longer fun for me.

Q: I was given a Miss Kim lilac bush for Mother's Day. It gets plenty of water but not standing water. Our soil is very hard clay, but we have fertilized and mulched around the base of the bush. We also made sure the planting hole was big enough to give the roots plenty of room.

However, it was green for only a couple of weeks and then looked like it was in need of water. The leaves are curled and browning and there are little, white dots on the stems. I don't really know if the dots are normal. I had trouble with this same type of bush at our previous house. What is wrong and what am I doing wrong?

A: I don't think you are doing anything wrong based on what you are telling me. I'm assuming you have it sited correctly in an area that gets full sun but is not baking on a southside brick wall. Another point is to check the planting depth. Many folks plant too deeply, which ends up causing the problems you describe.

The white dots could be oyster shell scale, which could spell trouble. Carefully scrape one off with your thumbnail to see if there is a little critter under it. If so, this would require a systemic insecticide, such as Orthene, to bring this pest under control.

Q: I have a flowering crab apple tree. It has partially bloomed two extra times this year. Is it because of our unusually cool weather?

A: The flower buds have a chilling requirement that releases the buds from dormancy to bloom. Sometimes a hormonal (florigen) imbalance results from the combination of shortening day lengths (photoperiods) and cool weather. The florigen, which is produced in the leaves, will trigger this partial blooming to take place.

Not much more is known about this influential hormone, so research breakthroughs are on the horizon for us! Thank goodness this doesn't happen on a wholesale basis or our food supply would be in jeopardy!

Q: I have a 4-year-old butterfly Japanese maple. This season, I have noticed many ants are on the tree. Should I be concerned? What can I do to prevent damage? I also noticed small sacs that look like they have puss in them.

A: The ants are harvesting honeydew, which probably comes from aphids in the tree. Look closely at the new growth and underside of the leaves. That typically is where aphids reside. Get rid of the aphids and the ants will disappear. There are many insect sprays available at garden centers and supply stores that you can use to control this very common pest.

To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or e-mail