Several plant viruses infecting temperate fruit crops are extremely infectious
and have devastating effects on the host trees. They all have a significant effect on
yield and yield-related efficiency. Others cause a slew of problems, necessitating a
large sum of money to save these infectious diseases from wreaking havoc. Yield and
other economic losses are the most visible manifestations of this effect. These viruses
cause economic loss to the farmers/producers and consumers by affecting plant growth
and reproduction, causing sterility, yield and/or quality reduction, increased
susceptibility to other stresses, crop failure, loss of aesthetic value, quarantine, and the
need for eradication of the infected plants, thus increasing the cost of control measures
as well as detection programs. Since future yield and risks are so unpredictable, losses
incurred by any viral disease cannot be calculated explicitly. Experimental evaluation
of the losses due to viral diseases is difficult because the infection of safe, controlled
plants is rarely possible, and inoculations under vector-proof conditions do not
adequately represent what occurs in natural conditions. Viruses are also unusual, and
their structures are deceptively simple. However, this simplicity leads to a stronger
reliance on the host, and the two have a complicated relationship. This complicates
plant-virus management strategies as well as the damage caused by them. Plant virus
control systems rely on our knowledge of the virus-vector/host relationship and will
remain one of the most difficult tasks faced by plant virologists, growers, and
nurserymen in the future.
Keywords: Economy, Fruit crops, Loss, Soil-borne viruses, Temperate viruses, Viral diseases.
