Wet Weather Diseases

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News Article for May 2, 2016:

When growing plants, whether farming or gardening, you are always at the mercy of the weather. Needless to say, this year is no exception. We have had a wet winter and spring which makes for problems.

One very prevalent problem that I am seeing and hearing about is brown patch in lawn grasses. You might remember that I wrote about seeing a lot of brown patch back in the fall and thought that it might be a real problem. With the amount of wet weather we have had and lack of cold to force all the grasses into dormancy brown patch is a big problem now.

Brown patch is a fungal disease that affects the leaves of lawn grasses. You will see it as circular or oblong patterns of grass dying in the lawn and can encompass a large area. Some literature will list the disease as large patch because of the wide expanse of the damage.

When the disease starts it can show up as small spots of yellow or orange tinted grass. As the fungus spreads outward it may look just brown. The disease rarely kills the grass but will cause a rot at the base of the leaves and this is what makes the leaves fall off. Your grass will get very thin and weeds usually will invade the vacant areas.

Even though the leaf blades fall off, stolons, which are runners that help the grass to spread, will still be alive. It is along the stolons that leaf development will re-emerge in a few weeks. The starting point of the disease will be the first place to regenerate leaves so you get a donut effect, with a bare area in your lawn that has a patch of green grass blades in the center.

The fungus that causes this problem likes wet moderate weather. Usually the problem will go away when we get sustained daytime temperatures above 85˚F. So this is a fall, winter and spring problem for us.

If you have the problem I would treat with a fungicide to try to minimize damage now. Recommended fungicides include Spectricide Immunox, Green Light Fung-Away, Fertilome F Stop , Bayer Advance Fungus Control for Lawns and Bonide Infuse Systemic Disease Control for Lawns. Make three applications about 10 days apart to the infected area and also spray a buffer zone of several feet outside of the infected area.

Buckeye rot is another wet weather disease that I am seeing on tomatoes. The disease is caused by a fungus that thrives in water soaked areas. The tomato fruit will turn black to brown but it looks more like the color of used motor oil to me. This starts on the green fruit in a wet year like this but it can show up as the tomatoes get ripe and will get very watery to the point that the tomatoes will burst in your hand as you try to pick them.

There is not a good fungicide spray control available to homeowners for buckeye rot. The best advice is to pick the infected fruit and remove it from the growing area. The fungus can be spread by splashing water so mulches help.

All citrus trees like good drainage and with an overabundance of surface water they can drop fruit. Do not confuse that with all of the small pea size citrus fruit you might be seeing fall now. Most of the satsumas are having a banner year of blooming and setting small fruit, many more that they can sustain. The trees will shed the excess fruit that they cannot support. In some cases citrus trees can drop as much as 90% of the small fruit and still have a bumper crop of mature fruit this fall.

For more information on these or related topics contact Kenny at 225-686-3020 or visit our website at www.lsuagcenter.om/livingston.

5/11/2016 3:40:33 PM
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