Nonchemical Control of Insects and Diseases on Strawberries

Strawberries are relatively easy to grow. However, insects and diseases occasionally cause problems. Fortunately, good cultural practices can reduce the damage and losses caused by these pests. The following practices should reduce insect and disease problems in strawberries.

1. Select a planting site with good soil drainage. Avoid poorly drained, wet sites. Poorly drained, wet soils favor the development of destructive root diseases. Gardeners with poorly drained soils should plant strawberries in raised beds.
2. Select a planting site where strawberries, tomatoes, potatoes, peppers, and eggplants have not been grown within the last 5 years to minimize the risk of Verticillium wilt, red stele, and other root diseases.
3. Plant only disease-free strawberry plants obtained from a reputable mailorder nursery or garden center. Plants from an old bed are often disease infested.
4. Control weeds in and around the strawberry planting. Weeds reduce air circulation. Poor air circulation increases the drying time in the planting, resulting in greater disease problems. Also, some weed species harbor insects and are hosts for Verticillium wilt and nematodes.
5. Apply a layer of straw mulch between rows and around plants. The mulch prevents soil from splashing onto the berries. The mulch also keeps the fruit off the soil surface and helps control fruit rots.
6. Strawberry plants should be watered deeply once a week during dry weather. The best ways to irrigate strawberries are with a soaker hose or trickle system. These methods keep the foliage dry and discourage diseases. If using an overhead sprinkler, water early in the day so the plants dry quickly.
7. Avoid applying nitrogen-containing fertilizers to June-bearing strawberries in spring. Nitrogen fertilizers produce dense foliage that increases drying time in the planting and also results in softer berries that are more susceptible to fruit rots.
8. Harvest berries as soon as they are ripe. Overripe fruit may attract insects to the garden and are more susceptible to fruit rots. Promptly pick damaged or rotting berries and remove them from the planting.
9. Renovate June-bearing strawberries immediately after the last harvest. Mow off the foliage with a rotary mower within 1 week of the last harvest. Rake and remove the plant debris to aid in disease control.

For additional information, see IDEA 2 Small Fruits - Insect and Disease Management for Backyard Fruit Growers in the Midwest
This article originally appeared in the May 1, 1998 issue, p. 49.