AMES, Iowa — Fresh strawberries, a favorite of almost everyone, are relatively easy to grow and hardy throughout Iowa. Horticulturists with Iowa State University Extension and Outreach share cultural practices to reduce damage and losses caused by insects and diseases. Gardeners with additional questions may contact the ISU Hortline, firstname.lastname@example.org or 515-294-3108.
The foam-like masses on the strawberry plants were probably created by the meadow spittlebug. The meadow spittlebug is one of several species of this commonly recognized group of sap-feeding insects. Spittlebugs are familiar because of the frothy, wet mass of “spittle” that surrounds the nymphs as they feed on sap from their host plants. The spittle is produced by the immature stage of the insect (the nymph) and protects the nymphs from natural enemies and desiccation.
While the foam-like masses of spittlebugs are rather disgusting, spittlebugs cause little harm to plants. Control efforts are usually not warranted.
The gray, velvety growth on your berries may be gray mold. It is also known as Botrytis fruit rot. Gray mold is favored by poor air circulation and a high humidity in the strawberry planting. The most commonly infected berries are those touching the soil or other infected berries.
Cultural practices can reduce losses due to gray mold.
Harvest strawberries when the fruit are uniformly red (fully ripe). Pick the berries with the caps and stems attached to retain firmness and quality. Pinch off the stem about one-fourth inch above the cap. Don’t pull them off.
Strawberries should be picked about every other day in warm weather, every three to four days in cool weather. The harvest period for some June-bearing varieties may last three to four weeks. Strawberries can be stored in the refrigerator for up to five to seven days. Optimum storage conditions are a temperature of 32 F and a relative humidity of 90 to 95 percent.