
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: SUNDAY, September 12, 1993                   TAG: 9309130317
SECTION: HOMES                    PAGE: E-2   EDITION: METRO 
SOURCE: John Arbogast
DATELINE:                                 LENGTH: Long

`EARLY BLIGHT' IS THE SUSPECTED CULPRIT

Q: About a month ago (letter was dated Aug. 13) I noticed the bottom leaves on my tomato vines turning brown and dying; now nearly half of some of my vines are dead. I have been spraying with Manzate 200 since the first bloom appeared in early June to control blight; also Sevin (insecticide) spray has been used on them. I have several different varieties in two different locations and all seem to be affected. We have been watering them during extremely dry weather. I also had a nice patch of Silver Queen sweet corn. When it got about knee high, a small wind storm blew over all the corn in the middle of the patch and left what was around the outside standing. After examining it, I wasn't surprised to find it down because it simply didn't have enough roots to support the stalk; there was no sign of any corn root worms. The corn that survived has done real well; some stalks had two nice ears each. Please give advice on these problems. R.F., Pearisburg

A: Your tomato problem sounds like the fungus disease called "early blight," since the oldest leaves dying first fits the pattern of that disease. However, the fungicide Manzate 200 is recommended to control early blight if used on a repeated seven- to 10-day interval. Of course, this fungicide might not have worked completely if your tomato plants were of poor vigor. Do JOHN ARBOGAST you recall seeing the two clues of early blight? They are older leaves with dark brown spots with circular rings within the spots, and gray to brown lesions on plant stems?

Since it's probably too late now to take a representative plant sample to your local Giles County Extension Office, be sure to practice good garden sanitation this fall. Remove all diseased plant parts as well as dead plants promptly while those items are still visible rather than waiting until spring when some of those diseased parts will have disintegrated into the soil.

Also, consider any possible explanations for why your tomatoes might have been of poor vigor this year and work to correct those factors for '94.

Corn doesn't grow a deep root system. You didn't mention how you cultivate or rototill your corn patch, but if you or your garden tiller works too close to the corn plants, you'll cut off the ends of the corn roots. That, of course, would increase the chances of incidents like you experienced.

Two other possible explanations for your corn situation and the lack of anchoring roots would be seeding depth and the amount of nitrogen. As you probably know from past gardens, sweet corn should be seeded at a 1-inch depth in average clay soils, but a slightly deeper planting is practiced in looser soil types. Was your soil different between the middle of your corn patch and the edges? The fact that sweet corn is known to fall over from too much nitrogen suggests that the initial fertilizer amount for corn should be worked in evenly and that side-dressing for corn with 10- 10-10 should be done lightly and also evenly.

Q: Do you have any information on English walnut trees? I have a beautiful large tree that is at least 15 years old. For the last three years it has been loaded with tiny nuts. The first year all fell off. Last year at least four made it to maturity. This year, so far, one or two are still hanging on and growing (letter dated June 20). What would cause this to happen? J.H.L., Dublin

A: I've had trouble in the recent past finding information to "trouble shoot" nut tree problems for home gardeners from Extension specialists at Virginia Tech. However, I did find some possible causes to your problem from an out-of-print Extension bulletin.

First, it would be helpful to know if your English walnut tree ever did produce nice nuts, what variety of English walnut are you writing about, and if you have more than one variety growing in your yard. The failure of your tree to mature nuts may be the result of a variety that is not hardy.

The Carpathian Persian walnut is a hardy type of English walnut which can be grown in Virginia. Even with that, though, Carpathian walnuts need a growing season of about 160 days. Another possibility is that the flowers of your tree may not be getting enough pollen to produce a normal crop. Some English walnut varieties cannot pollinate their own flowers, meaning that at least two different varieties must be planted to provide cross-pollination if nuts are to be produced.

Contact your local Pulaski County Extension Office at 980-7761 to discuss these possibilities and possibly bring in samples to be sent to Virginia Tech if necessary.

Yuccas wanted

Lois Hash from Roanoke writes: "I will remove the candle flower yucca plants that B.L. from Roanoke (Aug. 8 "Dear John") wants to get rid of if he/she will call me. I would like to have them. My phone number is 563-9942 or 384-7266.

Send short questions about your lawn, garden, plants, or insects to Dear John, c/o the Roanoke Times & World-News, P.O. Box 2491, Roanoke, Va. 24010-2491. We need your mail, but this column can't reply to all letters. Those of wide appeal will be answered each week. Personal replies cannot be given. Please don't send stamped envelopes, samples or pictures.

John Arbogast is the agricultural extension agent for Roanoke.

by CNB