Control Plant Diseases
Better Farming And Better Living BP 8-3 March, 1957

Indiana Tomato Disease Control Recommendations For Commercial Growers*

Numerous and frequent applications of suitable fungicides offer the only means yet found of satisfactorily controlling certain serious leaf blights and fruit rots of tomatoes in Indiana, The diseases occur here because of a predominantly humid summer climate o They are very minor diseases; if they occur at all, in certain arid western tomato growing areas.

The available fungicides are most cheaply and effectively used in spray form. They are best applied at weekly intervals because of their unfortunate and rather rapid breakdown after application on the plants.
Such frequent application is often also made necessary by mid- and late-
season weather conditions very favorable for disease development on the maturing tomato crop. Where intervals between sprays must be longer, the rate of fungicide applied per acre should be increased as indicated below.

Two Alternative Spray Schedules

Maximum disease control can be expected only when these weekly applications are started early in the season and continued until a week or 10 days before the end of harvest. For such control; as many as 14 applications may be required in some wets humid seasons. Sometimes a turn in weather conditions in August or early September make twice-a-week spray applications necessary for the degree of disease control desired.

Such an extensive spray schedule needs to be started well before the developing fruit load pulls apart the vines of upright-growing varieties. Such a schedule is costly and may be justified only where a high yield potential has been built into the crop through the best of cultural practices; with some help from summer weather.

A lesser but often very practical degree of disease control may he expected from as few as 5 weekly spray applications; starting after the fruit load has opened up the plants and after some leaf blight has appeared. But at best; such an abbreviated spray schedule cannot be expected to give the degree of disease control now generally asked for,

*For Insect Control Recommendations Refer to Purdue Extension Mimeo E-63, "Tomato Insect Control"

PURDUE UNIVERSITY Agricultural Extension Service, Lafayette, Indiana Departs *nt **f Botany and Plant Patholoav. Life Science Buildina