Pythium Disease
Destroys Watermelon Seedlings
(continued)
•At least some cultivars show moderate to
high levels of resistance to Pythium root rot.
•
•Plant mortality among cultivars ranged
from 33% to 100%
Air
Temperature
•Air temperatures during the first of June
were cooler than normal. These cool
temperatures may have contributed to the problems caused by Pythium.
The following graph the maximum, minimum, and average air temperatures
recorded at Lane during the first half of June, 2003.
Soil
Temperature
Soil temperature greatly affects the
growth rate of Pythium, and the damage caused to
watermelon by
Pythium. The following slide shows the maximum, minimum, and
average soil temperatures at a 2 inch depth during the first 15 days of June,
2003. The temperatures are lower
than normal for this time of year.
Rainfall
•Pythium
is a problem primarily during wet weather.
Rainfall during the first half of June, 2003, totaled 3.79 inches.
•
•There
were 138 different 5-minute periods during these 15 days in which rainfall was
recorded.
Photos
of Diseased Plants
The following photos are of plants
taken from the affected planting.
The lesions and discolorations are typical of those that would be found
with Pythium and perhaps other soilborne pathogens.
