Abstract

Kamal Sharma and Raj Shekhar Misra

Information on virus diseases of maize still remains scanty in several maize growing countries.
Therefore it is hoped that this description will stimulate more research, which will lead to better
understanding of viruses infecting maize in Africa. Plant viruses are a major yield-reducing factor for
field and horticultural crops. The losses caused by plant viruses are greater in the tropics and
subtropics, which provide ideal conditions for the perpetuation of both the viruses and their insect
vectors. Management of viral diseases is more difficult than that of diseases caused by other
pathogens as viral diseases have a complex disease cycle, efficient vector transmission and no
effective viricide is available. Traditionally, integration of various approaches like the avoidance of
sources of infection, control of vectors, cultural practices and use of resistant host plants have been
employed for the management of viral diseases of plants. All these approaches are important, but most
practical approach is the understanding of seed transmission, symptom development, cell-to-cell
movement and virus multiplication and accurate diagnosis of viruses. This update aims to continue on
this course while simultaneously introducing additional levels of complexity in the form of microbes
that infect plants. Rather than serving as a standard literature review, the objective is to provide a broad
conceptual introduction to the field of molecular plant-microbe interactions, virus multiplication,
transmission and virus diagnosis and various immunodiagnostic and molecular diagnostic methods
such as enzymes linked immunosorbent assay (ELISA), immunosorbent electron microscopy (ISEM),
polymerase chain reaction (PCR), nucleic acid hybridization, dot immunoblotting assay (DTBIA) found
suitable for diagnosis of viruses infecting maize. These techniques do not only provide information for
epidemiological purposes, but also help to develop disease free stock of maize. Therefore, these
various techniques with symptoms and history are of immense value to diagnose maize viruses and are
the cornerstone of the management of maize viruses. This information will be useful to researchers in
understanding of maize viruses. Information on symptomatology, transmission, geographical
distribution and properties of viruses is summarized here based on literature review.