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Poster: Biology & Disease Mgmt: Chemical Control


Effectiveness of fungicide treatments following the Strawberry Advisory System for control of Botrytis fruit rots in Florida
L. CORDOVA (1), A. Amiri (2), N. Peres (3) (1) University of Florida, U.S.A.; (2) Washington State University, U.S.A.; (3) University of Florida, U.S.A.

Botrytis fruit rot (BFR) of strawberry is caused by Botrytis cinerea. Its management was traditionally carried out by weekly fungicide applications using multi-site fungicides in early season and single-site fungicides during bloom when the environment is conducive for disease development. Recently, many Florida growers have been following the Strawberry Advisory System (SAS) to improve timing and reduce the number of fungicide applications. Our objective was to determine the efficacy of different fungicides for BFR control when following the SAS spray timing alerts compared to preventive Calendar-based applications, and to implement specific fungicide recommendations on SAS. Field trials conducted during two seasons on a commercial farm in Plant City-FL showed that during the highest disease incidence periods, treatments with cyprodinil + fludioxonil or fluopyram following SAS and Calendar-based applications were the most effective in controlling BFR. Pyrimethanil and boscalid + pyraclostrobin were not effective due to resistance problems and are no longer recommended in the SAS. For SAS alerts during absence of bloom, a multi-site fungicide such as captan or thiram is recommended. Treatments following SAS provided good control of BFR with about half the number of fungicide applications compared to Calendar-based applications. However, the choice of the fungicide when weather conditions are highly favorable for disease development is the key for effective control.