Methods for Managing Viral Diseases in Plants

Plant viruses have a huge impact on crop production throughout the world, leading to significant financial hardship and food insecurity, especially in developing countries.

Accurate diagnosis backed up by reliable detection techniques is the critical first step in virus disease management as it helps in implementing effective management strategies.

Insect-transmitted viruses cross national boundaries into new geographic areas, resulting in negative social and economic impacts on subsistence agriculture, creating challenges for virus management strategies.

<p>At the end of the lecture, the student should be able to distinguish viruses from other types of plant pathogens, explain the basic procedures of diagnosing viral crop pathogens, and explain the various measures of managing plant viral diseases.</p> Signup and view all the answers

<p>A virus is a nucleoprotein that multiplies only in living cells and has the ability to cause disease, parasitizing cells and causing a multitude of diseases in all forms of living organisms.</p> Signup and view all the answers

<p>Virus management strategies require a good understanding of how viruses spread between crops and across seasons to effectively deal with the challenges of virus diseases.</p> Signup and view all the answers

<p>quarantine, eradication, crop rotation, and certified virus-free stock</p> Signup and view all the answers

<p>due to health and environmental concerns</p> Signup and view all the answers

<p>through conventional breeding and genetic engineering</p> Signup and view all the answers

<p>scouting and removal of symptomatic plants, use of clean tools and equipment, crop rotation, and isolation of newly received plant material</p> Signup and view all the answers

<p>exposing infected plants to high temperatures to inactivate the virus</p> Signup and view all the answers

<p>infecting a plant with a milder strain of a virus to protect it from a more severe strain; labor-intensive, expensive, and poses a risk to alternate crops or varieties</p> Signup and view all the answers

<p>Insecticides and biocontrol products are used to control insect vectors as a means to control vector-transmitted viruses. This has been done by spraying insecticides to reduce the vector populations. However, the effectiveness of chemical treatments in controlling the virus depends on virus/vector relationships.</p> Signup and view all the answers

<p>Insecticide treatments may be ineffective in controlling non-persistently-transmitted viruses because their acquisition, latent, and inoculation periods are so short that the virus is acquired and transmitted before the vector can be affected by most insecticides.</p> Signup and view all the answers

<p>Quarantine (domestic or international) is one of the measures of managing virus diseases at the government level.</p> Signup and view all the answers

<p>One technique is meristem tip culture coupled with chemotherapy and/or thermotherapy. Another technique is cryotherapy for the elimination of viruses from already infected plant tissue.</p> Signup and view all the answers

<p>Integrated Plant Virus Management is an approach that combines selected multiple management strategies based on knowledge of the biology of a target virus. It relies on the correct identification of the virus and a good understanding of the virus biology and the virus disease epidemiology.</p> Signup and view all the answers

<p>The effectiveness of chemical treatments in controlling viruses depends on virus/vector relationships.</p> Signup and view all the answers

<p>Managing insect vector populations in the field can be difficult or impossible unless coordinated at government or intergovernmental level, on a regional basis.</p> Signup and view all the answers

<p>Plant viruses come in different shapes and sizes, with nearly half being elongated (rigid rods or flexuous threads). Most elongated viruses are about 15x300nm, while flexible threads are 10-13nm wide and 480-2000nm long.</p> Signup and view all the answers

<p>Viruses move from cell to cell through plasmodesmata and multiply in infected cells. Most viruses reach the phloem and move rapidly over long distances. Symptoms develop when the virus moves beyond the initial infection site. Some viruses are limited to the phloem and nearby cells, while others are systemic and affect all living cells.</p> Signup and view all the answers

<p>All infections result in dwarfing or yield reduction. Localized infections cause chlorotic or necrotic lesions at points of entry. Latent viruses infect hosts without symptoms. Masked symptoms may appear under certain environmental conditions. Acute symptoms may lead to death or partial recovery. Common symptoms include mosaics and ring spots. Less common symptoms include stunting, dwarfing, leaf roll, yellows, streaks, pox, enations, tumors, pitting, and flattening.</p> Signup and view all the answers

<p>Plant viruses are transmitted through vegetative propagation, mechanical transmission through sap, seed transmission, pollen transmission, insect transmission, mite transmission, and nematode transmission.</p> Signup and view all the answers

<p>Most elongated viruses are about 15x300nm, while flexible threads are 10-13nm wide and 480-2000nm long.</p> Signup and view all the answers

<p>Viruses move from cell to cell through plasmodesmata, reach the phloem, and move rapidly over long distances within the plant.</p> Signup and view all the answers