Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, April 25, 1993 TAG: 9304260396
SECTION: HOMES PAGE: D-6 EDITION: METRO
SOURCE: John Arbogast
DATELINE: LENGTH: Medium
A: I wouldn't relate your vegetable garden problems to your use of organic materials for mulches. However, there could be a problem for all vegetable plants if the grass clippings used around them as mulch had been treated with weed killers or even a weed and feed material.
The death of your cucumber vines might be caused by a disease called "bacterial wilt." This disease can cause the damage your cucumbers have experienced and cause it early in the cucumber growing season. With this disease, cucumber leaves will start to wilt during the day but may recover at night initially. Soon, all the leaves on one or more branches of the cucumber vine or the entire plant will wilt and die. As the name describes, this disease is caused by a bacteria that grows within the vine and causes the vine's plumbing system to become clogged up. That bacteria is carried by the cucumber beetle and is introduced into vines by the beetle's feeding. The young stage (larvae) of the cucumber beetle will live in the soil around the plants.
There is no chemical control for bacterial wilt of cucumbers. Suggested control strategies include: rotate cucumber growing locations; look for and grow cucumber varieties that claim resistance to bacterial wilt (very few varieties are available with this particular resistance); control cucumber beetles with several repeated applications of the insecticide diazinon or the organic control sabadilla used according to label directions; and plan for some cucumber plant loss early and replanting in early July.
Even if bacterial wilt or some other disease has occurred in your cucumbers, another condition that allows the vines to grow 8 or 10 feet long without bearing even one or two small cucumbers must be afflicting the plants. Do your cucumber vines bloom? Cucumber plants need full sun in order to be productive. The cucumber flowers need to have bee activity to spread their pollen. The very first cucumber flowers will be male and thus incapable of producing fruits. Also, if you're growing a seedless cucumber variety, blooms will form, but a regular cucumber variety will be needed for pollination.
Your late-season tomato problem sounds like the fungus disease called "late blight." However, other factors were likely involved if the crop was lost in a matter of days. I would recommend the following: Use only disease resistant tomato varieties; rotate your tomato planting locations if possible; and practice good garden sanitation.
As soon as problems occur this year, call (387-6113) and take a fresh sample to your local Cooperative Extension Office. In Salem, the office is located at 962 Kime Lane.
Got a question about your garden, lawn, plants, or insects? Write to Dear John, c/o the Roanoke Times & World-News, P.O. Box 2491, Roanoke, Va. 24010-2491.
New hours for calls
Because of increased demands, horticulture calls to the Roanoke City Extension Office will only be taken between 9 a.m. and 2 p.m., Monday through Friday, beginning the first weekday in May.
As always, those with plant questions and/or samples should contact their own local Extension Office. This request is based on the way the Cooperative Extension is set up. Local agents and technicians are hired to serve specific cities and counties; specialists who serve the state are found at land grant universities and research stations.
John Arbogast is the agriculture extension agent for Roanoke
by CNB