294 M. BABADOOST
in wind-driven rain in the air. Sporangia may either germinate directly
and infect the host plant or produce zoospores that are released in water
and infect the plant. The pathogen grows within the host tissues and
produces sporangia on the surface of the infected tissues.Phytophthora
capsicialso produces chlamydospores on culture media, but their role
in pathogen survival and diseases epidemiology is not known (Islam
et al. 2004).
Soil moisture conditions are important for disease development. Spo-
rangia form when soil pores are drained, and they release zoospores
when soil is saturated (soil pores are filled with water). The disease is
usually associated with heavy rainfall, excessive irrigation, or poorly
drained soil. Frequent irrigation increases the incidence of the disease.
Warm conditions (24â30âŚC) are favorable for disease development.
- Disease Management.Management ofP. capsici is a challenging
task, as no single method is available to provide adequate control of this
pathogen (Babadoost 2004; Hausbeck and Lamour 2004). Various dis-
ease control practices can be integrated to manageP. capsiciin cucurbit
production. Major methods for managingP. capsiciare exclusion, cul-
tural practices, and the use of fungicides.
Exclusion.The most effective method for control of Phytophthora dis-
ease in cucurbits is to preventP. capsicifrom moving into a non-infested
field.Phytophthora capsicispreads by soil, water, and plant material. It
is highly recommended to thoroughly clean all farm equipment that is
used in an infested field before moving it to another field. Also, avoid
using water sources (e.g., ponds or reservoirs) that receive run-off water
from an infested field (Hausbeck and Lamour 2004). Water sources can
be tested for the presence of the pathogen by baiting techniques.Phy-
tophthora capsiciis not considered a seed-borne pathogen; however,
saving seed from a field where Phytophthora infection occurred should
be avoided.
Cultural Practices.The following cultural practices can help to man-
age Phytophthora diseases in cucurbit fields. BecauseP. capsicican sur-
vive in soil for several years (Larkin et al. 1995; Lamour and Hausbeck
2003; Pavon et al. 2008; Babadoost and Pavon 2013), fields without a
history of Phytophthora infection should be selected for raising cucur-
bits whenever possible. Crop rotation of 4 years with a nonhost and
effective weed control should be considered (Tian and Babadoost 2004;
Babadoost and Pavon 2013). Fields that do not have history of cucur-
bits, eggplant, and peppers for at least 3 years should be considered.
Fields should be selected that are well isolated from fields infested with
P. capsici. High soil moisture favors the development of Phytophthora