Ask a Master Gardener: Beet canning and tomato growing tips to tackling pesky Japanese beetles

Q. I want to can beets in a couple of weeks, and many are ready to harvest. Should I harvest and store them or leave in the ground? How would I store them if I do?

A. Harvest the beets that are at the ideal size now. Leave any others in the ground until you are ready to can. Some may have sized up in that time so that they will be worth processing. Beets store very well. Wash them and trim the tops short, to about of an inch. Then store in a container that can breathe just a little, and keep them moist.

Q. My tomatoes twisted up recently, and I'm trying to figure out why. I did put some freshly mowed grass clippings around them - could that be a problem?

A. Yes the grass clippings appear the source of the problem, as you confirmed (during a hotline phone conversation) your neighbor used some lawn weed herbicide. And then you got those clippings. These types of herbicides don't kill grass, but kill other plants, which are generally referred to as "broadleaf plants," e.g. beans. The chemical or chemicals (referred to as active ingredients) can be taken up in the vegetation that is mowed. When applied under or around tomatoes they can be either released into the air or washed into the soil. The tomatoes' growth can be slightly to severely affected, depending on how much the plants absorb. To use lawn clippings following any herbicide use, one should wait about three weeks.

You are not the first or the last to learn this the hard way, but we hope your question will help some others avoid the situation. Also, tomatoes are quite sensitive to the various lawn weed herbicides, thus we also advise not applying them anywhere near tomatoes (stay at least 10 feet away), making sure plants are upwind of any spraying, and applying only during cooler spring weather (daily high temperature 70 degrees or less) if tomatoes are anywhere nearby. Spot spraying is not as risky as treating an entire lawn.

Q. Will Japanese beetles be a problem again this year, and when will they get bad? Which plants should I worry about, and what can I do?

Japanese beetles are expected to be a problem this year. The adults you'll see develop from grubs that live in the soil from September through June. They first started in the Jefferson City area around 2006 or 2007, and we began trapping them at the extension center about 2008. They became worse each year, hitting "plague stage" in 2012. But that was the drought year, so when they laid their eggs, the soil was so dry few developed. Thus, in 2013, we had very few, and last year their numbers returned to about half of 2012's.

We aren't sure how bad they will be this year, but probably plenty annoying. They have actually started to emerge; we caught some by June 8. Their numbers start slow for the first couple of weeks, and they peak in a typical year about July 4. This year has been more or less normal for their development, whereas last year they ran about two weeks late. This year they should wrap up their adult phase toward the end of July, tapering off in the middle of that month.

We suggest tolerating them as much as possible, but if they damage plants too much, the recourse now is to spray. Any systemic insecticides used as a soil drench need to be used a week or two before they are expected to arrive (which is early June). Some plants they like are roses, grapes, raspberries and blackberries; spoiling or damaged stone fruit (e.g. peaches); and corn silks. Unfortunately, the most effective insecticide against them is Sevin (active ingredient carbaryl), which is very toxic to bees. So, if using it, apply at dusk and use a liquid formulation. The "dust" formulations of Sevin are particularly toxic to honeybees.

The local Master Gardener hotline is staffed from 12:30-4:30 p.m. Tuesday and Friday afternoons; call 634-2824 then or anytime to leave a message. The Central Missouri Master Gardeners are a volunteer group of 191 members, 122 of whom are Cole County residents, who maintain 11 beautification sites in Cole County. Master Gardeners must complete a basic training program of at least 30 hours of horticultural training including landscaping, lawns, vegetables, flowers and fruits, as well as 30 hours of volunteer service.

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