Watch for Japanese beetles and plant diseases

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By Roberta Hunt

The Japanese beetles are back! The last few years they haven’t been as bad because of natural diseases that have built up over time since they moved in, as well as trouble they have had lately in hard droughty soils. However, this year with the wet soils, they should have no trouble getting out of the soil or laying eggs. Damage by Japanese beetles is pretty easy to identify because they eat leaf and bloom tissue and leave the veins. This makes the plant look lacey. You will probably notice them on roses first, and then grapes, and so on. My scout plants, so to speak, are usually fragrant roses. They attack them first.

To control Japanese beetles, spray with liquid sevin. The powder works but is ugly and not quite as effective as the liquid. Be sure to follow the label directions on mix rates and wait times before working in the sprayed plants and when eating any vegetables sprayed with sevin. Sevin is deadly to bees, so don’t spray when they are active. Early in the morning or late in the evening is the best time to spray to avoid killing honeybees.

Plant diseases are running rampant with the warm weather so a few things to keep an eye on are roses, tomatoes, peppers and other vegetables, as well as grapes.  There are several diseases that attack these plants. Tomato diseases generally start at the bottom and work their way up with early blight being the most likely disease right now. To control early blight or other tomato diseases, spray with maneb, mancozeb or daconil. Be sure to spray the undersides of the leaves as well as the tops. Also, we got word from UK Plant Pathologists this week that late blight has been confirmed in Kentucky on tomato. Late blight generally isn’t too bad here, but once it gets started in your garden it develops rapidly. To give you an idea how bad late blight can be, it was the disease that caused the potato famine in Ireland in the 1800’s where a million people starved to death!

With peppers and most vegetables, anthracnose is starting to attack and the sprays listed above will work well to control them too. Peppers also are starting to get bacterial spot and a  few sprays of fixed copper will help.

Grapes are getting walloped right now by black rot. This will start on the leaves as spots and will eventually cause the grape clusters themselves to rot. Immunox is very effective against black rot but be sure to read the label closely because it is systemic and you have to have a month or two wait time before you can eat the grapes.

Speaking of Immunox, it works pretty well on black spot on roses and should be something that most gardeners should have in their garden “medicine cabinet”. It controls a lot of diseases and can be put on some edible crops. Immunox is the brand name of this product so you should ask for it by name. I am not sure if there is a generic out for home gardens yet. 

Happy gardening!