Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, August 14, 1994 TAG: 9408160060
SECTION: HOMES PAGE: B-1 EDITION: METRO
SOURCE: John Arbogast
DATELINE: LENGTH: Long
A: Brown rot does develop rather quickly in a fashion you noted, but infected plums should stay on the tree rather than all falling. Also, I don't believe that brown rot can occur on grapes. A grape disease called black rot starts as a small bad spot before the whole young grape is involved, but again the rotted grape sticks on the vine. The fungicide captan, which was in the orchard spray you used, should have helped with either of those problems if coverage was good and timing was right. So, since unrelated plants had similar symptoms and the pattern doesn't fit a disease that I can think of, some site- related factor might have been to blame. I can't answer the fly-ash question, but dry soils can cause stressed young fruits to drop.
Without knowing the history of your fruit plants as well as this problem, I can make two recommendations: practice good sanitation around these fruit plants by raking and removing all fruits from the ground plus do proper pruning this fall or winter; and if any problem occurs next year, take fresh samples to your local Extension office for diagnosis and consultation.
Q: When is the best time to take the bottom limbs off my white pine tree that has never been trimmed? C.H.P., Roanoke
A: It would be OK to remove lower pine limbs now. However, this is not a good time to do any other pruning on a pine.
Q: Our 8-foot-tall Japanese Maples tree did well until early last year when the bark at the base of the tree began cracking and several small branches died. This year, the cracking has spread and bark has actually peeled off in places. A major limb budded but never leafed out and is now dead, even though the tree continues to grow. The soil is compacted clay. The cracking is occurring on three of our other maples. These plants are all in sunny locations. M.B., Wytheville
A: Peeling indicates drying of the wood beneath the bark, usually a result of death of the wood. The symptoms indicate that the maples have been stressed by any number of adverse conditions. Some possible explanations:
Weather, which would include rough conditions that happen at a specific time, such as freezing damage as well as accumulative stresses such as repeated years of summer droughts or low winter temperatures.
Physical bumps or injuries from the lawn mower, weed eater, animals, etc.
Localized disease, particularly "cankers," which are areas of infection caused by a definite pathogen and resulting in weakening and/or death of affected plant parts.
To save your maples act on all the possibilities that make sense to you; engage a trained and experienced tree professional to make a site visit, which will result in recommendations; and prevent all adverse conditions that might affect the trees.
Q: In the spring a lawn service applies a pre-emergent crabgrass killer (liquid) and a weed and feed dry powder. The lawn stays crabgrass and weed free until early July when clumps of crabgrass appear as well as clover and chickweed. Spot killing these weeds is a chore. Is there some other way to control crabgrass and weeds throughout the summer? R.H.K., Moneta
A: Three points:
Generally, weeds should not easily invade a dense, vigorous, properly managed lawn. The first line of defense should be to practice good management of your lawn, paying particular attention to a mowing height that's not too short for the type of grass you have since crabgrass and possibly other weeds readily invade grass mowed too short. Soil testing every three years and overseed with improved grass varieties.
Many pre-emergent controls for crabgrass should be effective for only about eight weeks, so depending on that type of chemical will mean making a second application, possibly at partial strength, in early summer.
Midspring and midfall are generally the preferred times to make broadleaf weed control applications where necessary for the whole year. The dry weed-control application for leafy weeds you mentioned must not be very effective, which is often the case when weed control granules fall to the ground (rather than adhere to weed foliage as liquids do) where the chemical can be absorbed by the weeds. I realize that your dry application can not be totally criticized without knowing the ingredients in your weed and feed.
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 stamps, stamped envelopes, samples, or pictures.
by CNB