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CHOOSE TOMATOES THAT ARE RESISTANT TO TOMATO SPOTTED WILT VIRUS
POSTED
FEBRUARY 26, 2010
There’s good and
bad news for those of us that enjoying growing (and eating!)
homegrown tomatoes. Bad news first: Tomato Spotted Wilt Virus (TSWV)
and bacterial wilt continue to devastate tomato plants in the South.
Good News: Tomato plants resistant to TSWV are easy to find across
North Florida.
The varieties of
tomatoes that home gardeners commonly grow here are likely to be
resistant to such common diseases as Fusarium, Alternaria and
Verticillium, but not bacterial wilt or Tomato Spotted Wilt Virus.
Plant breeders
have been working to develop new disease-resistant varieties. While
they have not had great success with the bacterial wilt problem,
they have developed outstanding tomato cultivars that are more
resistant to Tomato Spotted Wilt Virus.
One of the new
varieties resistant to TSWV is called Amelia. Commercial growers in
Florida are having good success with this new cultivar. The fruit is
large (8 oz), uniform, red, firm and aromatic. I grew Amelia
tomatoes last season and was very pleased with the fruit.
Here are the
varieties of TSWV-resistant tomatoes that I am familiar with:
Amelia, Bella Rossa Hybrid, BHN 440, BHN 640, Fletcher, and
Talladega. This year I am growing Bella Rossa, Fletcher and
Talladega. Most will be available locally; seeds are available on
the Web.

Tomato
seedlings under grow lights.
Here are my tips for healthy, tasty
tomatoes:
-- Grow only disease-resistant,
determinate tomato plants. Determinate tomato varieties generally
reach a fixed height and ripen all their fruit in a short period of
time.
-- Grow your tomato plants in containers
using a high quality potting mix (not soil). I prefer to grow them
in a self-watering container such as an EarthBox. It keeps plants
evenly watered and makes nutrients readily available, both keys to
producing a vigorous plant and better flavored tomato. Also, it
protects your plants from nematodes and saves water.
-- Add calcium to the upper half of the
potting mix or use a fertilizer that has at least 4% calcium added
(I use ground up eggshells or a bit of dolomite or garden lime.
Calcium nitrate also works but be careful not to over do it).
-- To insure that your tomato plants
can take up the calcium, choose a fertilizer that uses a nitrate
form of nitrogen. Ammonium nitrogen should be only a minor component
because excess ammonium ions reduce calcium uptake. This leads to
blossom-end rot as well as poor tasting tomatoes.
-- Keep plants evenly moist. Don’t let
them dry out.
-- Use a Bt product (such as Thuricide
or Dipel) when you see signs of tomato worms. Repeat in 10 days.
This natural insecticide is produced by the bacterium Bacillus
thuringiensis (called "Bt") that has been used for decades by
organic farmers to control crop-eating insects and by the World
Health Organization to kill mosquitoes without using dangerous
chemical pesticides.
-- Try a natural product, something
using a pyrethrin as the active ingredient, for other insects.
Pyrethrins are natural insecticides produced by certain species of
the chrysanthemum plant. Liquid Rotenone/Pyrethrin is a good one
that also includes rotenone as an active ingredient. Rotenone is an
odorless chemical that is used as a broad-spectrum insecticide and
pesticide. It occurs naturally in the roots and stems of several
plants such as the jicama vine plant.
-- Use a liquid copper-based fungicide,
or biofungicide, as a preventative for disease. Be careful not to
burn the leaves of your plants with the copper-based fungicide. I
have great success with Soap Shield and Plant Guardian biofungicides
from Gardens Alive.
If you chose to grow tomatoes in the
ground, you can increase their flavor by using similar techniques.
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