Maize Dwarf Mosaic

 

Maize Dwarf Mosaic


This disease is caused by the maize dwarf mosaic virus (MDMV). Several strains of the virus exist. They are denoted as A,B,C,D,E,and F. Two other strains have also been identified. Strain A and B are commonly detected in Nebraska. MDMV has over 200 cultivated and weed hosts. Important cultivated hosts in Nebraska are corn and sorghum with sweet corn being more susceptible than dent corn. Johnsongrass is the most important weed host because it serves as the overwintering reservoir for strain A. The virus survives between crops in the underground stems (rhizomes) of this grass.

Strain B does not survive in Johnsongrass and enters northern parts of the corn belt via migrating vectors. Several species of aphids serve as vectors of MDMV. The most common vectors in Nebraska are the corn leaf aphid (Rhopalosiphum maidis) and greenbugs (Schizaphis graminum). Infection can occur anytime during the growing season. MDMV is also seed transmitted in sweet corn.

Symptoms


Symptoms are variable on both corn and sorghum. Plants infected early in the season are more severely affected than those planted later. The exception to this observation is in sweet corn where late plantings are more severely affected than those in early plantings.. Infection sites in the field are sporadic. They may exist as individual plants, clusters or "hot" spots in the field or in rows along the edge of the field (often in close proximity to Johnsongrass). When plants are infected early in the growing season mosaic symptoms develop on youngest leaves and appear as yellow streaks with dark green "islands". Infected plants are also stunted and produce small ears with a low seed set. As the growing season progresses and temperatures rise, mosaic symptoms fade and infected leaves appear yellow. If cool night temperatures (60oF) occur infected sorghum leaves develop a red discoloration (red leaf). Reddened areas increase and merge then become necrotic. The red leaf symptoms is most common with a strain B infection.

Plant Health Management

References

Useful Links

Caveat

This description is presented for information only and no endorsement is intended for products listed, nor criticism meant for products not mentioned. Always consult the product label before purchasing and using any pesticide.

Material contained on the Links from the page are the responsibility of the linked page's author(s).

This page was drafted by: Jane Christensen, Department of Plant Pathology, University of Nebraska-Lincoln

Disease images were provided by: Dr. David Wysong, Department of Plant Pathology, University of Nebraska-Lincoln

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This page is authored and maintained by:
Dr. J.E. Partridge, Department of Plant Pathology, University of Nebraska-Lincoln

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Copyright (C) 2003 J.E. Partridge, University of Nebraska-Lincoln. All Rights Reserved.