The Issues at Hand
The Strawberry Nursery Industry is highly complex and faces several challenges.
Propagation material can be a symptomless carrier of plant pathogens.
This frequently leads to plants being delivered to growers only to show disease later in the fruit production process. Species of Collectotrichum (Anthracnose) could be traced back to nurseries in more than 150 cases over the past decade in North Carolina, Florida and California’s south coast. Other diseases such as Botrytis (grey mold), angular leaf spot (Xanthomonas fragariae) or Powdery mildew (Podosphaera phanis (syn. Sphaerotheca macularis) are frequently believed to be traced back to strawberry nurseries.
The dependency on Methyl Bromide (MB) for soil disinfestation by the majority of nurseries.
Nursery growers use MB and chloropicrin as soil fumigant to reduce nematode and disease pressure on planting stock. Without MB, the risk to introduce soil-borne pathogens such as Phytophthora root rot, Pythium and Rhizoctonia spp. root rot, Fusarium oxisporum or Macrophomina phaseolina increases significantly. This problem is exacerbated by stricter regulatory changes, requiring the use of less effective fumigants and higher costs for fumigant applications. Strawberry nursery operations in the US rely currently on critical use exemptions for MB as pre-plant soil disinfectant, issued annually by the EPA. Looming stricter regulations would make it more difficult for the nursery industry to produce pathogen free transplants, increasing the vulnerability of the current strawberry farming industry in the US.
Technology used by the industry is impacted by environmental factors.
The plasticity of different strawberry cultivars in their response to environmental factors leads to frequent underperformance of propagation rates as well as the unintended development of flowers and fruit in propagation fields, increasing the risk to introduce diseases. Data derived from several preliminary experiments at NC State show that under precisely controlled light levels and controlled cultural techniques, high propagation rates can be achieved in a short period of time, while flower production can be regulated by altering nutrient protocols. The current reliance on multiple locations and multiple seasons increase the vulnerability of the strawberry nursery industry to the plasticity of environmental and weather-related factors.
The current multi-year and multi-location propagation processes are costly.
Increasing costs for additional labor (such as flower removal), labor shortages, increased transportation costs, higher fixed costs for duplicative infrastructure and equipment are a drain on the current strawberry nursery system. The need for multiple locations and multiple years, costly transportation, increased need for labor, while at the same time propagating under potentially underperforming conditions with the threat of symptomless spread of plant pathogens are obvious problems, affecting the whole strawberry supply chain.
This work is supported by Specialty Crop Research Initiative (SCRI), Grant no. 2021-51181-35857, Project accession no. 1027418, sponsored by the USDA National Institute of Food and Agriculture. Please use this link for more information.