Agriculture Reference
In-Depth Information
Chapter 10
Control of plant disease through
soil solarization
Abraham Gamliel
1
and Jaacov Katan
2
1
Agricultural Research Organization Volcani Center, Bet Dagan 50250, Israel
2
The Hebrew University, Rehovot 76100, Israel
10.1
Introduction
Soil-borne pests, including pathogens, weeds and arthropods, cause heavy losses to all
major crops, especially when they are grown frequently in the same soil. Many methods
for the management of these soil pests have been developed, with differing levels of
success. These include chemical, physical, biological and cultural methods. In addition
to effective pest control, pest-management programs need to consider the environmental,
economic, technological and legal issues.
Soil disinfestation is one of the most effective means of controlling soil-borne pests and
improving plant health. Soil disinfestation is a drastic means applied to soil before planting
in order to reduce or eliminate populations of soil pests (Katan, 1984). The basic idea is to
eradicate the pests at the desired soil (or substrate) depth, before planting. This is usually
achieved by applying a drastic physical or chemical tool which has the capacity to penetrate
the soil and reach the inoculum at each site within it. Usually, these eradicants exhibit a wide
range of control over many organisms, and are detrimental to the crop as well. They should
therefore be applied such that they will have enough time to dissipate before planting. Until
the 1970s, there were two major approaches for soil disinfestation, both of which had been
developed by the end of the nineteenth century, in the early days of modern plant pathol-
ogy: physical soil disinfestation, mainly by heating the soil with steam, and chemical soil
disinfestation, using fumigants. However, fumigants have always been the major tool for
soil disinfestation, methyl bromide (MB) being foremost among them since the 1950s and
until recently. A third approach, soil solarization (also called solar heating of the soil, SH)
was introduced in 1976 (Katan
et al.
,
1976; Katan & DeVay, 1991).
The main principle of SH is to harness solar energy in order to raise the temperature
of a moistened soil. Mulching (covering, tarping) the soil with transparent polyethylene
or any other transparent plastic sheet is, at present, the most common means of carrying
out this task. Future technologies may provide simpler, more effective and less costly
tools to capture solar energy for plant protection. The use of sprayable plastic polymers
(see further on), instead of laying plastic fi lms, may revolutionize SH. Attempts to use
solar energy for controlling biotic agents in soil and in plant material have been known
for decades, even centuries (Katan & DeVay, 1991). For example, Hagan (1933) heated
