- OOMYCETE DISEASES OF CUCURBITS 289
Fig. 6.1. Devastation in a pumpkin field caused byPhytophthora capsici.Courtesyof
Christine Smart, Cornell University.
of the cucurbit-producing areas in the world (Ristaino 1990; Erwin and
Ribeiro 1996; Gubler and Davis 1996a; Zitter et al. 1996; Latin and Rane
1999; Babadoost 2000; Lee et al. 2001; Davidson et al. 2002; Hausbeck
and Lamour 2004; Islam et al. 2004; Babadoost and Zitter 2009).Phy-
tophthora capsicicommonly occurs in temperate, subtropical, and trop-
ical environments. This pathogen infects more than 50 species in 15
plant families; however, the main hosts are cucurbits and peppers. Crop
losses up to 100% byP. capsiciin cucurbits (Fig. 6.1) have been reported
from many areas in the world (Ristaino 1990; Erwin and Ribeiro 1996;
Zitter et al. 1996; Babadoost 2000; Lee et al. 2001; Hausbeck and Lamour
2004; Babadoost and Zitter 2009). Major diseases caused byP. capsiciin
cucurbits are damping-off, crown rot, vine blight, leaf spot, and fruit rot.
- Symptoms. Damping-off. Phytophthora capsicicauses damping-off
in cucurbits under wet and warm (20â30âŚC) soil conditions, similar to
that caused byPythiumspp. (Erwin and Ribeiro 1996; Gubler and Davis
1996a; Babadoost 2004; Hausbeck and Lamour 2004; Islam et al. 2004).
In seedlings, a watery rot develops on the hypocotyl at or near the soil
line, resulting in plant death. Post-emergence plant death is preceded
by a sudden, permanent wilt of the plant without a change in color
of the foliage. Plants often die within a few days of the first symptom