The harvest of June-bearing strawberries will begin in a few weeks. As home gardeners begin harvesting fruit they may encounter a few insect and disease pests. Possible pest problems include gray mold, sap beetles, and spittlebugs.
Gray mold is a gray, velvety growth on ripening berries. 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.
The following cultural practices can reduce losses due to gray mold.
- Do not fertilize June-bearing strawberries in spring. The application of a nitrogen-containing fertilizer in spring promotes lush, vegetative growth. Dense foliage slows the drying of the strawberry planting, resulting in a more favorable environment for gray mold.
- Control weeds in the strawberry bed. Weeds reduce air circulation and slow the drying of the strawberry plants.
- Mulch the planting with straw to keep the berries off the ground. Berries resting on damp or wet soil are more susceptible to gray mold.
- During dry weather, irrigate in the morning when using a sprinkler. Plants dry quickly when irrigated in the morning.
- Harvest berries as soon as they ripen. Strawberries should be picked about every other day in warm weather, every three to four days in cool weather.
- "Clean-pick" the strawberry planting. Berries that exhibit symptoms of gray mold should be picked and removed from the bed.
- Handle berries carefully during harvest to avoid bruising the fruit. Immediately refrigerate the unwashed berries.
Fungicides are used by commercial strawberry growers to control gray mold. However, cultural practices are the best way to control Botrytis fruit rot in home gardens.
Sap beetles are small, shiny black, yellow-spotted insects. They also are known as picnic beetles or picnicbugs. Sap beetles commonly feed on overripe or damaged fruits and vegetables in the garden.
Sanitation is the best management strategy for sap beetles in home gardens. Keep the strawberry patch as clean as possible through timely picking and removal of damaged, diseased, and overripe fruit.
Insecticide sprays are available for sap beetles, but they are difficult to use because they are applied to a crop that is ready for harvest or while harvest is underway. If you do spray, use an insecticide with a short harvest-waiting interval and follow label directions carefully.
Spittlebugs produce white, foam-like masses on strawberry plants. The small, foam-like masses can be found on leaves, petioles, and stems. Spittlebugs feed on the sap of their plant hosts. A frothy, wet mass of "spittle" is produced by the immature stage of the insect (the nymph) and protects the nymph from natural enemies and desiccation.
While the foam-like masses of spittlebugs are conspicuous and rather repugnant, spittlebugs cause little harm to plants. Control efforts are usually not warranted.
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on May 20, 2016. The information contained within may not be the most current and accurate depending on when it is accessed.