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Botany and Plant Pathology
and Horticulture Mimeograph No. 5.
February, 1944
REPORT ON TOMATO SPRAYING DEMONSTRATIONS IN 1943'
R. W. Samson, Department of Botany and Plant Pathology and
I. D. Hartman and Ernest Nordlinger, Department of Horticulture

Introduction—Results of Previous Experiments
In 1938 the authors started a series of experiments-to determine
whether spraying or dusting of canning tomatoes for disease control
is practical and profitable under Indiana conditions. .'Power-driven
spraying and dusting machines designed for row crops were used. These
machines were of types readily available on the market at the time
the experiments were started. Certain copper fungicides known to be
effective in the control’of tomato diseases were also used. The fun-
gicides were applied about as a good tomato grower or operator of a
custom spraying or dusting outfit might be expected to apply them.
The results of these experiments..ware-not very convincing.
Slightly more.marketable tomatoes were harvested from the sprayed or
dusted plots than from the untreated plots, but the differences in
yield were hardly great enough to indicate commercial feasibility
of spraying or dusting canning tomatoes in Indiana.
The amount of disease control-, as. measured by the extra tomatoes
harvested from the sprayed or dusted plots, was not as great as the
authors had reason to expect. This may have been because of the
rather low level of disease development in the experimental fields
or because the equipment used did not thoroughly cover the plants
and fruit with spray or dust.

Nature of the Experiment in 1943
Various circumstances made it inadvisable to continue the
experiments with the row-crop duster and sprayer in 1943* Instead,
the authors conducted 12 trials of a single spray material,^under
quite varied conditions with respect’to location of the individual
trials, time of setting of the plants!, soil fertility, rainfall and
disease development. The spray material was 4-2-50 Bordeaux mixture.
It was used because it is one of the .most effective fungicides known
for the control of tomato .diseases. In order to obtain as much disease
control as possible it was applied at an excessive, rate of more than
300 gallons per acre with a spray rod attached to a small orchard
sprayer transported in a light truck. All leaves, stems: and fruits
were almost completely covered with the material. All sprayed plots
received 3 applications and some of them 4 applications where the
additional spray, s eemec| d es,i.rable. The first spray v/as applied
about July 30 and was repeated at 10-day intervals.^ It Was not
possible to apply this first spray until after considerable leaf spot
and some fruit rot had occurred in many of the plots.
A single plot* was sprayed in this manner in each of .12 cooperating
farmers1 tomato fields distributed as shown in table'*1. The plots
varied from approximately l/6th to l/8th acre in size. Each spraye
Plot, wi th pne except ion. was f lanked„.on..bot h._s id_es„by. .un spray,ea„ c hep
Purdue University Agricultural Experiment Station
Lafayette, Indiana