COLUMN

Tomato diseases and ticks

By John Fulton, University of Illinois Extension

[August 21, 2013]  It seems like the tomato is the one plant that just about everybody tries to grow. Some people grow large amounts, while others plant one or two in containers. At any rate, the calls and samples have started coming in to the office with the recent swings in weather. Most of the samples have spots, brown leaves and dropping leaves, or all of the above.

Several diseases hit tomatoes, but two of the more common ones are early blight and septoria leaf spot. Blossom-end rot seems has also accelerated with the drier weather pattern returning, particularly with plants grown in containers and hanging baskets.

As for what to do, here is the checklist: First, keep ripe fruits picked off the plants. Second, don’t work around tomatoes when they are wet. Next, you can try to improve air circulation, but if your tomatoes are severely affected, you won’t want to lose any more leaves. And the final step for this year is to try a fungicide. Mancozeb is probably the recommended one, but it is very hard to find. The other options are Daconil and maneb, which are easier to find but probably won’t control as well. The final step for future years is to practice at least a three-year rotation with good sanitation in the garden.

Blossom-end rot is a non-pathogenic disease that is very common during extended dry periods. It begins as a light tan water-soaked lesion on the blossom end of the fruit. The lesions enlarge and turn black and leathery. This can drastically lower the yield and lower marketability of the fruits. The major causal factors are fluctuating soil moisture supply during the dry periods and low calcium levels.

Control of blossom-end rot consists of providing adequate moisture from fruit formation to maturity and use of mulch (grass clippings, plastic, straw, shredded newspapers or plastic) to conserve moisture. The key is to provide even amounts of moisture -- not soaked, then dry.

Ticks

Tick numbers seem to be off the chart again this year. Anyone who has been out in tall grass or wooded areas can probably attest to that. Probably the frequent spring rains in much of the state have provided the high moisture and humidity that ticks need.

Ticks are large, flattened mites that feed as parasites on mammals, birds and reptiles. They hatch from eggs into six-legged larvae that locate hosts and feed before dropping off the host and molting into eight-legged nymphs. Nymphs locate hosts, feed and drop off to molt into eight-legged adults. Adults also locate hosts on which to feed. Males may stay on the host, mating with females coming there to feed. Females engorge on blood to several times their original size, drop off the host and lay hundreds of eggs. With each tick having to find three hosts in its lifetime, many ticks starve before reproducing, although ticks can survive for long periods without food.

Ticks are numerous in areas of tall grass, where humidity is high and hosts common. Mowing greatly reduces tick numbers. When walking or working in areas of tall grass or other areas with ticks, apply a repellent containing about 30 percent DEET, such as Off or Cutter, to the lower legs and pants legs. If ticks are numerous in mowed areas, spraying carbaryl, permethrin or bifenthrin should help give some control.

If a tick is attached, grasp the head with tweezers where the mouthparts enter the skin, pulling slowly and consistently. The tick will release its mouthparts and come loose. Do not handle the tick. Good luck trying to smash a tick. It’s about like trying to flatten a dime with a rubber mallet. Other methods such as heat and nail polish commonly kill the tick, resulting in locked mouthparts that remain in the wound to cause infection. A tick typically feeds for 24 hours before releasing disease organisms, so remove ticks promptly when you find them.

Also pay particular attention to pets in wooded areas or areas with tall grass. Use preventive products when possible. Carbaryl dust may be used on pets and their sleeping areas to help control ticks and fleas. For people, mosquito and tick repellents containing DEET can be used on clothing and body parts. Permethrin can be used on clothing only but not sprayed on the body. Be particularly careful of permethrin around cats and dogs, as it can be lethal.

[By JOHN FULTON, University of Illinois Extension]