Crop Protectants for Controlling Diseases of
Vegetable Crops in Greenhouses
Vegetable Disease Information Note 5 (VDIN-005)
Charles W Averre, Extension Plant Pathologist
S. F. Jenkins, Plant Pathologist
Paul B. Shoemaker, Extension Plant Pathologist
on chemical plant protectants for disease control on greenhouse vegetables
must be used in the context of a "Total Disease Control Program". For
example, many diseases are controlled by sanitation (no smoking, fumigating
soil, using disease-free seed and seedlings, removing all dead plant parts,
and washing hands and equipment before moving from one house to another),
use of resistant varieties, crop rotation, seed treatment, exclusion of
aphids from fall crops, and cultural practices. Always use top-quality
seed or plants obtained from reliable sources. Seed are ordinarily treated
by the seed producer for the control of seed decay and damping-off. However,
tomato seed also should be treated with Clorox to reduce the risk of tobacco
mosaic virus and certain bacterial diseases.
diseases can be reduced or controlled by maintaining relative humidity
under 90 percent, by keeping the air circulating in the house, and watering
in such a manner to avoid wetting leaves.
with fungicides should be done as to ensure coverage of all plant surfaces.
We recommend the use of high-pressure and high-volume equipment or subliming
products (Exotherm Termil). Application should start prior to or as soon
as the disease first appears and continued on a 7- to 14-day schedule
as needed. Before starting the spray schedule, be sure to obtain a diagnosis
of the disease in order to use the proper material. This information may
be obtained through the local county Agricultural Extension Office.
The risk of pesticide exposure in the greenhouse is high; use protective
clothing laundered daily or after each exposure; ventilate house during
application and use appropriate respirator. Always use the chemical
as directed on the label.
North Carolina Cooperative Extension Service
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of specific chemicals are based upon information on the manufacturer's
label and performance in a limited number of trials. Because environmental
conditions and methods of application by growers may vary widely, performance
of the chemical will not always conform to the safety and pest control
standards indicated by experimental data. All recommendations for pesticide
use were legal at the time of publication, but the status of registration
and use patterns are subject to change by actions of state and federal
regulatory agencies. 06/91/1000