A Greener View by Jeff Rugg

Q: The apples on my tree had been looking pretty good, but they have recently developed gray patches and tiny black spots. What is the cause, and what should I do about it?

A: Your apples have two problems. The first one is a fungal disease called sooty blotch. It is a designation for a disease pattern that is caused by several different fungi, but it all looks the same. It can be found on a lot of different kinds of plants.

It looks like a small patch of soot is stuck to the fruit, or sometimes it can cover the whole fruit. The spores are blown in the wind and can be splashed from fruit to fruit in the rain. It grows anytime in the summer that the fruit is wet. Thinning out the tree and keeping the weeds down will help air to circulate, which will dry the plant faster — then the disease can't grow. Fungicide applications need to be applied in wet weather, not in hot, dry summers.

Fortunately, it just grows on the surface and can be washed off. It harms the appearance, but not the fruit. You can eat the fruit after washing, or you can peel it and use it.

The small raised black spots are another fungal disease called flyspeck. It is only caused by one fungus species and not caused by flies. There can be just a few spots or sometimes dozens of spots. They may be clustered together or scattered all over the fruit. This disease can be found on at least 25 kinds of plants.

Flyspeck prefers cooler weather around 65 degrees and requires moisture. It infects plants in the spring and the fall. Creating better air circulation and fungicides are the two ways to help prevent it from getting on apples.

It is just on the surface of the fruit, but requires more scrubbing and using soap to try to wash it off. The skin can be peeled off and the fruit is fine.

Q: I planted tomatoes this spring with high hopes, but they didn't begin ripening until just this week. The plants have lost the leaves off their bottom half and look horrible. What can I do to fix this, or do I have to wait until next year? What do I do next year?

A: For most of the country, this was a bad summer for tomatoes and many other vegetable crops that ordinarily do fine. The reason is that most of the country had a cool, wet spring that didn't dry and warm up all summer.

Most of our garden crops require warm or hot temperatures, while most of the diseases like it cool and wet.

This was and still is a good year for diseases. Our plants got off to a poor start because many were planted late. The soil was cold and the plants didn't grow many roots, so the tops just sat there without many blooms. Without flowers, there isn't fruit.

Cool season plants like broccoli, chard and cabbage kept growing all summer when they normally die or go to flower. If you planted them in the spring, you can still be getting a crop.

The tomato plant is the poster child of this year's generally bad growing season, so let's look at them. They normally don't flower and fruit well if they have too much nitrogen fertilizer; it promotes leaves, not flowers. If the nighttime temperatures are above 70 or below 50, tomato plants often drop the flowers. They don't set fruit if the daytime temperature is over 85, if there is irregular watering or if there is extended cloudy weather. All it takes is one of those elements to stop production, and many places had several.

Once tomatoes have fruit, they ripen best with temperatures in the low- to mid-70s — temperatures out of that range delay production. The pigments that turn the tomato red don't develop when the temperature is over 85 degrees, so ripe tomatoes may not look very good.

If a warm-season vegetable plant is getting its needs met, it will outgrow small disease outbreaks. If it is doing poorly to begin with, a simple disease can overtake the plant. To get a disease, you must have three things all at the same time: a susceptible host, a pathogen and the proper conditions for infection. This summer, many garden vegetables have had fungal diseases because the cool and wet weather was the proper condition for infection.

There is nothing that can be done at this time. As the plants die and the fall frost finishes them off, remove the diseased material and bury it, or pack it up for the commercial compost facility in your area.

Next year, rotate the crops to new areas in the garden. Plant more disease-resistant varieties, knowing that nothing is 100-percent guaranteed to not get sick. Newer hybrids are often more disease resistant than older heirloom types. Plant several varieties of each crop. Give the plants good care, so they are healthy and strong when problems occur.

E-mail questions to Jeff Rugg, University of Illinois Extension at jrugg@illinois.edu. To find out more about Jeff Rugg and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.

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