Insects, of course, are not the only agents hazardous to crops. Once it becomes viruliferous, the vector will remain so for many days and such a relationship is therefore termed "persistent" or "circulative". At one extreme, the association occurs within the feeding apparatus of the insect, where the virus can be rapidly adsorbed and then released into a different plant cell. Bark scaling caused by Citrus psorosis virus. The viruses have the "machinery" to enter the animal cells directly by fusing with the cell membrane e.
Humans have carefully selected and cultivated plants for food, medicine, clothing, shelter, fibre, and beauty for thousands of years. Cancer, group of more than 100 distinct diseases characterized by the uncontrolled growth of abnormal….
Plant sciences technology In agricultural technology: This is because large numbers of the same species or variety, having a uniform genetic background, are grown close together, sometimes over many thousands of square kilometres.
Such losses from plant diseases can have a significant economic impact, causing a reduction in income for crop producers and distributors and higher prices for consumers.
The major means of control depending on the disease include: A pathogen may spread rapidly under these conditions. Fossil evidence indicates that plants were affected by disease 250 million years ago. The study of plant diseases is called plant pathology.
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In some examples of this type e. Written By: Contact our editors with your feedback. Arthur Kelman Michael J.
Chemical or biological control of the vector the organism transmitting the disease, often an insect: Why are viruses important?