Many home gardeners are expressing concern about the use of pesticides. Costs of spray materials, lack of proper application equipment, regard for the environment, and small acreage have been incentives to explore alternative means of pest management. Many gardeners become frustrated, however, when pests ruin a crop or render fruit inedible.
Growing fruits is very challenging. Tree fruits, in particular, are notorious for requiring a rigorous spray schedule. Berry crops tend to be more "forgiving," and have, in general, a much smaller pest complex to contend with. It is possible to grow berries using little or no spray material, especially if you judiciously choose appropriate crops and resistant varieties. This fact sheet ranks the berry crops in order of ease of growing ecologically.
Blueberries should be the easiest berry crop to grow ecologically. They have a relatively low nitrogen requirement and thrive on organic sources. Few insect and disease pests seriously affect blueberries, and most can be controlled to some extent through cultural manipulations. For instance, significant control of mummyberry disease can be obtained by a thorough, light cultivation of the soil beneath individual bushes just prior to budbreak.
Currants and gooseberries should also be relatively easy to grow ecologically for many of the same reasons as blueberries. Powdery mildew can be a serious problem on some cultivars of gooseberries, but many other good cultivars are resistant to this disease, and require no specific control program. Sulfur is available for effective control of mildew in existing plantings in which susceptible varieties are present, but will cause injury on some "sulfur shy" cultivars. Proper cultivar selection will be the key to growing this group of plants successfully.
Primocane-fruiting raspberries, often referred to as fall-bearing raspberries, are another good possibility. Because canes are cut and removed annually, certain cane disease fungi and insect pests do not become well established in the planting. Heavy rates of manure can be used to provide nitrogen since winter injury is not a problem when overwintering canes are removed.
Strawberries and summer-fruiting raspberries are more difficult to grow using ecological methods. Both have high nitrogen requirements, yet raspberries are sensitive to winter injury if nitrogen is available too late in the season. Virtually all important root and leaf diseases of strawberries (with the notable exception of black root rot) can be controlled by planting resistant cultivars. Unfortunately, the same cannot be said for fruit rots. To minimize fruit rot losses without the use of fungicides, the home gardener must concentrate on horticultural practices that maximize air movement (drying) within the fruiting zone (e.g., raised beds, narrow rows, and good weed control). Furthermore, an excellent mulching program after runner establishment will provide control of leather rot, in addition to suppressing weed growth.
On summer-bearing raspberries, training systems, such as the V-trellis system, that maximize air circulation also are very important for control of fruit rots and cane diseases. Additionally, lime sulfur, the mainstay of traditional cane disease control programs, is available to the home gardener. Perhaps the way to keep fruit rots from spreading is simply to pick as often as possible, and to get rid of any fruits that are beginning to show signs of infection. Growing strawberries and raspberries ecologically is certainly possible, but it does require the home gardener to be more diligent.
Marcia Eames-Sheavly, Extension Support Specialist, Fruit and Vegetable Science Department, Cornell University, Ithaca, NY 14853
Dr. Marvin Pritts, Associate Professor, Fruit and Vegetable Science Department, Cornell University, Ithaca, NY 14853