Tomatoes, Japanese beetles
The extremely hot weather we have had recently not only interferes with flower pollination but also can affect how quickly fruit matures. The best temperature for tomato growth and fruit development is 85 to 90 degrees Fahrenheit. When temperatures exceed 100 degrees, the plant goes into survival mode and concentrates on moving water. Fruit development slows to a crawl. When temperatures moderate, even to the low to mid 90s, the fruit will ripen more quickly.
Tomato color can also be affected by heat. When temperatures rise above 95 degrees Fahrenheit, red pigments don’t form properly though the orange and yellow pigments do. This results in orange fruit. This doesn’t affect the edibility of the tomato, but often gardeners want that deep red color back.
So, can we do anything to help our tomatoes ripen and have good color during extreme heat?
Sure, there is. We can pick tomatoes in the “breaker” stage. Breaker stage tomatoes are those that have started to turn color. At this point, the tomato has cut itself off from the vine and nothing will be gained by keeping it on the plant. If tomatoes are picked at this stage and brought into an air-conditioned house, they will ripen more quickly and develop a good, red color. A temperature of 75 to 85 degrees Fahrenheit will work well.
Japanese beetles feed on more than 300 species of plants including rose, birch, linden, crabapple, grape, Virginia creeper and buckeye. Adults are approximately 7/16-inch long and metallic green with coppery wing covers. They sport a series of white dots made up of tufts of hair that project from under the edges of the wing covers on the back half of the insect. This characteristic is used to distinguish Japanese beetles from other similar beetles.
Japanese beetles feed on leaves, flowers and wounded or mushy fruit. Adults often feed on the green material on the upper surface of the leaf leaving a lacelike or “cellophane” appearance. Most feeding activity occurs over a four to six week period though individual beetles usually live about 30 to 45 days.
Japanese beetles tend to be gregarious and feed in groups, starting at the top of a plant and working down. Warm, sunny weather is preferred with beetles favoring plants in full sun. When disturbed, adults fold their legs and drop from foliage. Adult beetles can be killed by shaking the beetles from the plant into a jar or bucket containing soapy water. This is best done in the morning when the insects are sluggish.
Numerous insecticides can be used including pyrethroid products such as cyfluthrin (Tempo, Bayer Vegetable and Garden Insect Spray), bifenthrin (Hi-Yield Bug Blaster II) and cyhalothrin (Bonide Beetle Killer, Spectracide Bug Stop Indoor + Outdoor Insect Killer, Spectracide Triazicide, Bonide Caterpillar Killer). Carbaryl (Sevin) can also be used. The pyrethroid products normally give two to tjree weeks protection with carbaryl not lasting as long, usually one to two weeks.
All of the above insecticides are detrimental to natural controls such a parasitoids and predators or other pests including the two-spotted spider mite. Neem products (Natural Guard Neem-Py, Fertilome Triple Action Plus) and Pyola (pyrethrins in canola oil) will provide deterrence for three to four days. Japanese beetle traps tend to attract more beetles than they kill and often do more harm than good and therefore are not recommended.
Matt Young29 Posts
Matt Young is the Brown County Extension District director, as well as an agent in the area of agriculture and natural resources.