Root & Vascular Diseases
For a larger view and narrative of each disease please click on the photo.
Photos provided by Tom Isakeit, Department of Plant Pathology, Texas A&M University.

FUSARIUM WILT - Causal Agent: (fungus - Fusarium oxysporum f. sp. niveum)

Vascular browning

YELLOW VINE - Causal Agent: (unknown, suspected to be a bacterium)

Phloem discoloration

SOUTHERN BLIGHT - Causal Agent: (fungus - Sclerotium rolfsii)

CHARCOAL ROT - Causal Agent: (fungus - Macrophomina phaseolina)

A water-soaked lesion develops around the crown of the plant, followed by the appearance of an amber-colored ooze at the surface. This area becomes dark brown, dried and cracked. Small black fungal structures (microsclerotia) are then formed in this area. A dark ring is visible beneath the outer layer when a cross section is cut through the canker. Infected plants have yellow leaves and die soon after symptoms are observed.

The damage is most severe when melons approach maturity. There are no effective controls for the fungus. Altering the irrigation program to prevent water stress may alleviate the problem.

MONOSPORASCUS ROOT ROT/ VINE DECLINE - Causal Agent: (fungus - Monosporascus Cannonballus)

Vascular discoloration
Root Lesions	Brown lesions on roots, Rhizoctonia and Pythium isolated

DAMPING OFF - Causal Agent: (fungi - Rhizoctinia solani, Pythium spp.)

Caused by Rhizoctonia solani

Caused by Pythium aphanidermatum

NEMATODES

NON-PATHOGENIC CAUSES

Seed corn maggot	Wilt caused by squash bug	Wilting caused by Trifluralin (herbicide) injury. Note swollen area of stem
Death by lightning	Squash bug, cause of anasa wilt	Glyphosate (herbicide) injury
	Movement on plastic