WWW.CLEMSON.EDU/PSAMEDIA

DATE:   3/29/01
WRTIER: Dr. Tony Keinath, Clemson Extension plant pathologist,
        (843) 766-3761
EDITOR: Giles Singleton, (864) 656-3876
     
Can garlic chives save tomatoes?

     CLEMSON -- When I have to tell a home gardener that their 
tomatoes were attacked by bacterial wilt, I know that I'm the 
bearer of bad news. There's nothing gardeners can do to save 
their tomatoes from this deadly disease.
     A few months ago a national gardening magazine offered gardeners 
a simple solution to controlling bacterial wilt: that planting 
garlic chives with tomato plants prevents bacterial wilt. Their 
simple solution was based on a scientific study that had several
shortcomings, and ultimately, questionable results.
     I reviewed the article that appeared in the Journal of Chemical
Ecology about planting garlic chives (Allium tuberosum) and tomatoes 
in soil artificially infested with the organisms that cause bacterial
wilt. However, there is a lot missing between the results of this
study, done with a model system, and real world conditions.
     For starters, the study was done with young tomato plants; 
results with young plants may not transfer to older plants. Also, 
in South Carolina, bacterial wilt does not attack young plants. 
Here bacterial wilt usually begins its attack after the plants have 
set fruit, mostly because the wilt bacterium needs soil temperatures
above 85 F to grow.
     Next, the experiments were done only for two or three weeks 
after the tomato and chive plants were planted in the infested soil. 
In the real world, tomato roots must be protected for twice that 
time, at least six weeks, from the time soil temperatures warm until
tomato fruit is harvested.
     The most important shortcoming of this study is that the chives
and tomatoes were grown in boxes that were only four inches deep. 
The boxes very likely limited the natural spread of the tomato roots.
More roots were in contact with, or protected by, the chive roots 
than would happen under normal growing conditions.
     The criticism of this study does not mean that interplanting
garlic chives with tomato will not help control bacterial wilt.
However, because the study was done under artificial laboratory
conditions, chances that garlic chives will help very much are low.
     The only way to know for sure is for gardeners to test this 
method under real world conditions.
     For ways to avoid bacterial wilt and other tomato diseases, 
see Clemson's Home and Garden Information Center's at
www.hgic.clemson.edu, Tomato Diseases, HGIC 2217, or call the toll-
free number, 1-888-656-9988. For more tips on growing healthy 
tomatoes, "Trouble-free tomatoes" is also available at
www.clemson.edu/psamedia, under 2001 Gardening Packet. You can 
also call your county's Clemson Extension office.
               *********************************
     If you have gardening questions, write to PSA Media Relations,
A-101 Poole Agricultural Center, Clemson University, Clemson, S.C.
29634-0129. You might also want to check our website at
www.clemson.edu/psamedia.
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