Management of Viruses by Alteration of Vector Efficiency and by Cultural Practices

The management of plant virus diseases may seem like simply a popular philosophy for the control of plant diseases; however, careful crop manage­ ment is as basic today for the control of most important virus diseases as the use of modern pesticides for control of other plant pathogens. Far too often, growers concentrate solely on producing a crop, and incidentally become concerned with the managing of virus diseases. But, as we wish to establish in this review, sound crop production practices exist which not only result in a better crop, but also can minimize virus diseases by altering vector efficiencies and by using crop management strategies. In many cases, these measures are the only options available for the control of plant virus diseases. The biological factors that account for virus spread are as intricate as one might imagine considering that three factors (host, vector, and virus) are closely involved. Plant viruses, more so than any other group of pathogens, depend almost totally on insect vectors for their dissemination, which al­ lows for some interesting phenomena. This almost total dependence is further complicated by the close association between host and pathogen