Effectiveness of a Low-volume Spray Technology in the Control of Major Strawberry Diseases in Florida

Abstract

Florida strawberry production is greatly affected by Botrytis and anthracnose fruit rots (BFR and AFR), caused by Botrytis cinerea and Colletotrichum acutatum, respectively. Fungicide applications are the most effective method for control of both diseases. Traditionally, Florida strawberry growers use sprayers mounted with hydraulic nozzles delivering high flow rates. The objective of this study was to compare the standard hydraulic nozzle (SHN) sprayer with the air-assisted rotary atomizer (AARA). The effects of low volumes on the control of BFR and AFR, the reduction of 25% on fungicide rate, and their operational efficiency were evaluated, and an economic analysis was conducted. Two experiments were conducted (in the 2014-2015 and 2015-2016 seasons) where three treatments were compared: two using the AARA at 25 gal/acre, one of these with 75% of the fungicide rate; and one using the SHN at 100 gal/acre. In the first season, yield, AFR control, and BFR control were similar for all three treatments. In the second, BFR control was similar among all the treatments. However, the AARA treatment had a higher yield than the SHN, with the AARA (75% rate) being more productive. The operational capacity in acres per hour of the AARA was 17% higher than the SHN. Labor and fungicide costs were lower in the AARA treatments. Thus, the technology was shown to be a good fit for Florida growers.Accepted for publication 25 October 2016.