Crop Profile for Strawberries in California - Regional IPM Centers

nurseries. Two or more field propagation cycles occur in low-elevation (less than 500 ft elevation)
nurseries in the state's interior valleys (primarily the Sacramento Valley) where climatic conditions
result in prolific runner production during a long growing season. A final field propagation cycle occurs
in high-elevation nurseries in northeastern California (at greater than 3,200 ft elevation), where
temperature and photoperiodic conditions limit nursery runner production but result in increased
transplant vigor, productivity, and fruit quality. Nursery location and nursery production practices effect
transplant performance in California strawberry fruit production systems (11).
Nursery stock for summer-planted fields comes from low-elevation nurseries located in the Central
Valley. These nursery fields are planted in the mid-Spring and harvested at the end of the calendar year.
The resulting nursery stock are trimmed, packaged, and kept in cold storage until transplanting into
fields the next summer. High-elevation nurseries are used for fall plantings. In these cases, harvested
nursery stock are used immediately for transplanting into production fields.
Fumigation:Several weeks before planting, in essentially all but the organically-grown acreage of the
state, the soil is fumigated with a combination of methyl bromide and chloropicrin applied under a
sealed plastic tarp, which is removed after about of 5 days (120 hours). Plants are set by hand into deep,
narrow holes on pre-moistened beds. If bed fumigation is used, plants are set through holes in the plastic
at least two weeks after fumigation, and the plastic mulch stays in place until the plants are removed.
Methyl bromide is scheduled for phase out over a 4 year period due to environmental concerns and will
be unavailable after 2005. The consequential rapid replacement of this pest management tool that is
currently essential to the industry's productivity will certainly have a major impact on the cultural
practices employed by the industry by the middle of the next decade.
Mulch: Mulch can be used to ensure that the strawberries and plant foliage are separated from the
ground. This reduces pathogen transfer, enhances soil warming and improves water management. If
mulch is used, it is put on immediately after planting. Typically, clear polyethylene mulch is applied to
warm the soil, increase early plant growth, and keep the berries off the damp ground. The color of the
tarp is important for efficacy and productivity. In Southern California, use of black or colored tarps can
reduce weed populations but result in a 10% yield reduction due to less effective soil warming.
Harvesting: The grower/shipper or shipper assumes control of all operations related to harvest. Once
harvesting commences, hand-harvesting continues for several months on a 3 to 5 day cycle. This
continual harvesting ceases when the productivity of the field diminishes significantly.
Strawberries are harvested carefully by hand and are not subject to washing at the time of harvest.
Harvested strawberries are placed in trucks, within an hour or two of picking, which transport the
strawberries to a cooling facility. All strawberries are cooled, usually within 1 to 4 hours after harvest.
Strawberries are typically forced-air cooled at temperatures of 34F. Cooling reduces decay and prolongs
the fruits shelf-life.
Nearly all strawberries are shipped to the market in refrigerated trucks, and temperatures in the range of