How to Manage Pests

UC Pest Management Guidelines

SYMPTOMS AND SIGNS

Seed rot causes the corn seed to rot before germination and damping off causes the seedling to die soon after emergence. Infected tissue may be water-soaked (Pythium), white to pink (Fusarium), or bluish (Penicillium). The stem of infected seedlings becomes brown and soft near the soil line. Aboveground symptoms include yellowing, wilting, and death of the leaves.

COMMENTS ON THE DISEASE

Seeds or seedlings may be predisposed to disease by several factors, including planting depth, soil temperature, soil type, seed quality, and mechanical injury to the seed pericarp. These diseases are more common in poorly drained, excessively compacted, or cold (less than 55°F), wet soils. Sweet corn, especially the supersweet hybrids, is much more susceptible than dent (field) corn.

MANAGEMENT

Use high quality seed and good cultural practices, such as planting seed in warm soil (above 55°F), proper seedbed preparation, optimum water management, etc. Sweet corn, especially the supersweet hybrids, may benefit from fungicide seed dressings, especially in poorly drained and cold soils. Seed treatments for field corn are usually not warranted.

Common name		Amount/Acre**	R.E.I.+
(trade name)			(hours)
SEED TREATMENTS
A.	CAPTAN 400	Label rates	0
	MODE OF ACTION GROUP NAME (NUMBER1): Multi-site contact (M4)
	COMMENTS: For sweet corn.
B.	THIRAM 50W	Label rates	24
	MODE OF ACTION GROUP NAME (NUMBER1): Multi-site contact (M3)
	COMMENTS: For sweet corn, add mefenoxam (Apron XL LS).
C.	METALAXYL
	(Apron) XL	Label rates	0
	MODE OF ACTION GROUP NAME (NUMBER1): Phenylamide (4)
	COMMENTS: For super sweet corn.
**	Apply with enough water to provide complete coverage.
+	Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing.
1	Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of actions. Fungicides with a different group number are suitable to alternate in a resistance management program. For more information, see http://www.frac.info.

PUBLICATION

UC IPM Pest Management Guidelines: Corn
UC ANR Publication 3443
Diseases
R. M. Davis, Plant Pathology, UC Davis

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