Breaking the epidemic cycle between disease in strawberry nurseries and fruit production fields

Authors: PERES, NATALIA - University Of Florida; Turechek, William; WANG, NAN-YI - University Of Florida; BAGGIO, JULIANA - University Of Florida; ZUNIGA, ADRIAN - University Of Florida

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/10/2018
Publication Date: N/A
Citation: N/A

Interpretive Summary: Clean planting stock is the foundation of an effective disease management program. For strawberry, producing clean planting stock is a challenge because transplants are produced remotely from fruit production sites under different growing conditions and climates. Recently, there has been a preponderance of evidence showing that many pathogens are harbored on transplants from nurseries. A thermotherapy protocol that relies on aerated steam (instead of hot water) and a pre-heat treatment step to condition plants was developed to eradicate bacterial and fungal pathogens from strawberry transplants. In numerous field trials, it was shown that aerated steam was less damaging to plants than hot water dipping and was proven effective in reducing several pathogens. In summary, thermotherapy treatment using aerated steam has great potential to serve as a non-chemical tool for general disease management and for nurseries to reduce fungicide resistant populations from their planting stock

Technical Abstract: Clean planting stock is the foundation of an effective disease management program. For strawberry, producing clean planting stock is a challenge because transplants are produced remotely from fruit production sites under different growing conditions and climates. Recently, there has been a preponderance of evidence showing that many pathogens such as Colletotrichum acutatum, Botrytis cinerea, Phytophthora cactorum, Podosphaera aphanis, and Xanthomonas fragariae are harbored on transplants from nurseries. Because the same limited groups of fungicides are often used in both nurseries and fruit production fields for managing diseases, fungicide resistance is a major problem. This is particularly evident in fruit production fields where essentially the last round of plants from a multi-year propagation cycle are planted. The lack of non-chemical alternatives, and the use of resistance-prone fungicide in nurseries sets the stage for the downstream problems experienced in fruit production fields. A thermotherapy protocol that relies on aerated steam (instead of hot water) and a pre-heat treatment step to condition plants was developed to eradicate bacterial and fungal pathogens from strawberry transplants. The use of aerated steam rather than hot water immersions reduces the risk of spreading microbial and nematode pathogens in treated batches. In numerous field trials, it was shown that aerated steam was less damaging to plants than hot water dipping. The aerated steam treatment was proven effective in reducing X. fragariae, C. acutatum as well as multi-fungicide resistant populations of B. cinerea on strawberry transplants. Preliminary results have also shown great potential for reduction of P. cactorum, including newly emerged isolates resistant to mefenoxam. In summary, thermotherapy treatment using aerated steam has great potential to serve as a non-chemical tool for general disease management and for nurseries to reduce fungicide resistant populations from their planting stock.