Ask a Master Gardener: From Japanese beetles to watering tips and avoiding blights

The Central Missouri Master Gardeners are a volunteer group who maintain beautification sites in Cole County. Master Gardeners must complete a basic training program of at least 30 hours of horticultural training, as well as 30 hours of volunteer service. The Missouri Master Gardener program is supported by the University of Missouri Extension.
The Central Missouri Master Gardeners are a volunteer group who maintain beautification sites in Cole County. Master Gardeners must complete a basic training program of at least 30 hours of horticultural training, as well as 30 hours of volunteer service. The Missouri Master Gardener program is supported by the University of Missouri Extension.

Q. Are Japanese beetles out now? With the dry weather, will they be as bad this year?

A. Yes and yes! Gardeners first started commenting on them around June 10. With the very warm temperatures, their populations will increase rapidly. Their populations often peak around the July 4 holiday period; they will likely do that this year, if not even a bit earlier. Get ready!

In the drought of 2012, their populations in and around Jefferson City were terrible. The drought impacted their population in following year, when their population crashed. They had to lay eggs into soil that was too dry in July and August, so very few grubs developed in the soil to hatch out as adults in 2013.

Q. Are we in a drought yet? Will this be as bad as 2012? What should I do for watering my garden and my yard?

A. The U.S. drought monitor map shows the entire Mid-Missouri region as "abnormally dry," effective June 16. With no rain over that following weekend and little forecast, we'll likely move to moderate drought. Our soil moisture, coupled with rainfall this year, is every bit as serious as 2012. The only positive difference between 2012 and 2016 is the dry weather is not extensive across the greater Midwest. This year, the dryness is primarily focused on Missouri and into southeastern Iowa. The cool spring helped preserve soil moisture from the winter, which had a lot following the flooding rains of November and December. But with the recent heat, that is dwindling rapidly. This is quite serious.

To reduce water use and protect plants, consider the following:

Let lawns go dormant now. Minimize any mowing.

Harvest spring vegetable crops that have finished, and leave those areas fallow until planting a fall garden. Water other plants with a soaker hose or similar methods at the base of the plants.

Water any trees, bushes or similar perennial plants, especially if they have been planted within recently. Most critical are any planted this year, but also those planted last year or in 2014 should be monitored. Keeping a plant OK is better than trying to get one to recover when it is already stressed.

Keep the area around the base of desirable plants weed and/or grass free - 1-2 feet for small plants (i.e., tomato or small bush), 3-4 feet for a moderate-sized tree and 6-10 feet for a large tree. Have mulch 2-3 inches in depth, and replenish as needed (typically in spring and/or fall).

Q. I have some kind of blight on my tomatoes and potatoes, maybe peppers too. I have been using neem oil, which is supposed to help. Is there anything else I can do?

A. Blight is a term commonly used to describe a disease affecting the foliage. Some natural or alternative products like neem oil may give short-term benefit. Watch the foliage over the week following an application to see if the condition worsens or improves. Reapply if it seems to help. If it doesn't, consider switching to a different product. Products containing copper (i.e., copper sulfate) have been proven to work, and it is a natural product (based on the element). Serenade is another natural product that uses a biological organism (commonly referred to as a biofungicide). A good synthetic is Daconil Liquid Concentrated Fungicide (active ingredient chlorothalonil). Be sure to read the label carefully, follow all instructions and heed any warnings.

Blights are aggravated by rain and heavy dews. Since we haven't had much rain, make sure to irrigate at the base of the plant, not with some kind of overhead sprinkler. Mulch helps reduce disease spread of soil splashing up on the lower leaves. Full sun is also important; plants grown where there is a fair amount of shade are more prone to blights. Lastly, keep sufficient nitrogen fertilizer for the plants. Nice, dark green leaves are better able to resist the blights.

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.

Have a gardening question of your own? The Central Missouri Master Gardeners hotline is staffed from 12:30-4:30 p.m. Tuesdays and Fridays; call 634-2824 then or anytime to leave a message.