Effects of Hot Water Treatment on Plant Performance, Bud Break, and Yield in Strawberry and Raspberry

Hot water treatment (HWT) is a promising non-chemical method for controlling pests and pathogens in horticultural crops, aligning with the increasing demand for sustainable and residue-free production systems. This study evaluated the effects of various HWT protocols on plant vigour, yield, and fruit weight in strawberry (Fragaria × ananassa) and raspberry (Rubus idaeus) under protected cultivation in Switzerland. Strawberry tray plants were treated at 18–20 °C (ambient), 37 °C, or 47 °C for 10 min prior to planting. Raspberry canes were treated at 18–20 °C, 40 °C, or 45 °C for either 10 or 60 min. In strawberries, no significant differences were observed in the number of flowering stems, flowers, yield per plant, and fruit weight. However, a trend towards lower yields and higher fruit weights has been observed at higher treatment temperatures, particularly 47 °C. In raspberries, bud break was negatively affected by higher temperatures, while leaf area, cumulative yield, and fruit weight remained unchanged across treatments. These results suggest that HWT can be integrated into berry production with minimal impact on plant performance, provided treatment parameters are carefully optimized. Further research is needed to evaluate pest control efficacy under real infestation conditions and to refine protocols for different cultivars and developmental stages.