profitable
Fruit Growing
through better production methods
Revised, I960	Mimeo HO-55-1
what's new in ...
fruit varieties • soil management • spraying and
dusting • fruit handling • fertilization • pruning
and thinning • storage • marketing
VIRUS-FREE STRAWBERRY PLANTS
Strawberry plants that are substantially free from disease-causing viruses are now available from many nurseries. Growers who plant virus-free strawberry plants can protect themselves from this common cause of serious strawberry losses. Virus diseases generally weaken plants, reduce runner formation and hold down yield.
Several damaging viruses have been found to be widespread in many sections of the United States where strawberries are grown. Often two or more viruses were found in the same plant. Two types of virus diseases, virus 1 (yellows) and virus 2 (crinkle), are rather widespread.	Virus-infected plants may
show a green-yellow mottling of the foliage in some varieties. Symptoms vary with the variety of strawberry, the ,particular virus or viruses present, the stage of plant growth and weather conditions. Some infected varieties show no obvious symptoms, while in other infected varieties the plants are stunted and runner production reduced. Healthy plants usually out-yield virus-infected plants.
The U. S. Department of Agriculture, in cooperation with State Agricultural Experiment Stations, has conducted a very successful program to find virus-free plant sources for most of the popular varieties of strawberries.
Such plants have been propagated to increase the number of plants available and have been released to coop rating nurseries throughout the United States. These nurseries have further increased the supply of plants so that an almost unlimited supply of virus-free plants of most varieties is now available.
Virus-free plants have been compared with the standard plants of the same varieties in experimental tests in many parts of the country. In some of these tests, the virus-free plants have not been superior to the standard plants, but in most of the tests, the virus-free plants have been more vigorous, produced more runners and have out-yielded the standard plants. In some tests the yields have been more than double those of the virus-infected plants. Since the virus-free plants grow more vigorously, they are better able to produce under adverse conditions.

Available Virus-Free Varieties
By 1960, virus-free plants of the following 33 varieties were generally available to growers:
Albritton	Marshall
Armore	Midland
Blakemore	Missionary
Catskill	Orland
PURDUE UNIVERSITY
Agricultural Extension Service  Lafayette, Indiana Department of Horticulture