Group Title: Press bulletin
Title: Tomato rust
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 Material Information
Title: Tomato rust
Series Title: Press bulletin
Physical Description: 2 leaves : ; 23 cm.
Language: English
Creator: Burger, O. F ( Owen Francis ), 1885-1928
University of Florida -- Agricultural Experiment Station
Publisher: Florida Agricultural Experiment Station
Place of Publication: Gainesville
Publication Date: 1913
Subject: Tomatoes -- Diseases and pests -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Statement of Responsibility: by O.F. Burger.
General Note: Caption title.
General Note: "April 5, 1913."
 Record Information
Bibliographic ID: UF00090318
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 82850519

Full Text




By 0. F. Burger
The tomato crops of Florida have been attacked from time to time by
a disease which is called in different localities and by different growers,
tomato rust, tomato blight, tomato leaf blight, or tomato black spot. This
disease should not be confused with fungus blight, or with the bacterial
b!iflht"of tomatoes, neither of which can be successfully controlled by Bor-
deaux mixture. Rust causes more Or less damage t othe crops, mainly ac-
cording to the local climatic conditions. In some years the only evidence
of the disease may be a few dried leaves on the tomato plants, while in other
years all the leaves are destroyed and the tomato fruits are much spotted.
Symptoms of the Disease
Sometimes the tips of the leaves become brown and dried, the rest of
the leaf blades remaining green, or becoming more or less spotted with brown.
At other times small brown spots appear at once on many of the leaves,
and spread rapidly so as to destroy the whole of these leaves. The stems
and fruits usually remain green after all the leaves have been destroyed. In
advanced stages of the disease the tomato stems and fruits are affected, as
well as the leaves. The stems become spotted with brown spots, which
frequently grow together, forming a brown crust. Brown circular spots
appear on the fruits. These spots often make their appearance after the
fruit has been picked and packed. When such tomatoes arrive at the market
they are sold as inferior fruit, or thrown away.
Preventive Measures
The disease can be successfully controlled by spraying the tomato plants
with Bordeaux mixture. 'Bordeaux mixture is made of quicklime and blue-
stone (copper sulphate). Three pounds of copper sulphate and three pounds
of quicklime in fifty gallons of water have been found sufficiently strong to
prevent rust. If properly made. it may be used'as strong as six pounds of

April 5, 1913

copper sulphate and six pounds of quicklime to fifty gallons of water, with-
out scalding the plants.
Bordeaux mixture is not a cure, but a preventive. It will not cure an
infected leaf, but if it is applied to a healthy leaf in such a manner that the
whole surface is covered with a film of the mixture it is impossible for it
to become infected.
It is best to commence spraying while the plants are in the seed bed.
They should receive' two or three good sprayings before being taken to the
field. The disease does not prove destructive with sufficient regularity to
warrant spraying every year; but we should always be ready for it. When
the plants in the field show symptoms of the disease we should be prepared
to spray them thoroughly at once. Two or three sprayings at least are
Required to get the disease under control. The disease depends a great
deal on weather conditions. The grower cannot foretell the weather condi-
tions, so preparations should be made to ensure against loss from this dis-
Cause of the Disease
Tomato rust is caused by a fungus called Alternaria solani. This fungus
is propagated by small brown club-shaped bodies, known as spores. The
spores are so small that they can be seen only by the aid of a microscope.
They are carried by the wind from one plant to another. The spore lodges
on the upper side of the leaf, and, if there is enough moisture, it will germi-
nate. A small tube grows out from the spore, penetrates the skin of the
leaf, and kills and feeds on the leaf tissue, causing a dead brown spot.

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