Effectiveness of Some Environmentally Friendly Products on Hazelnut Powdery Mildew Caused by Erysiphe corylacearum

Abstract

Objective: Powdery mildew disease caused by Erysiphe corylacearum is one of the main diseases affecting the yield and quality of hazelnut (Corylus avellana L.), one of the most important agricultural products of Türkiye. The study was conducted in Giresun in 2017 to determine the effect of some environmentally fiendly products (one biological fungicide, one fungicides containing plant extract and one plant activator) against the disease.
 Materials and Methods: As environmentally fiendly products against to disease, commercial products including AQ 10 (Ampelomyces quisqualis M-10 isolate), Regalia (Reynoutria spp. extract) and ISR 2000 (Lactobacillus acidophilus fermentation product) were used. For comparison Quadris Maxx (Azoxystrobin 200 g/l+Difenoconazole 125 g/l), a chemical fungicide known to be effective against this disease, was also used in the study. A total of five spraying applications beginning at the fruit setting time, prior to appearance of disease symptoms were performed. Disease severity values on hazelnut leaves and fruits were calculated according to the Townsend-Heuberger formula using the 0-4 scale. The efficacy of fungicides was determined using Abbott’s formula. 
 Results: The effectiveness of AQ 10 (Ampelomyces quisqualis M-10 isolate) was 21.07% on leaves and 21.29% on clusters; for Regalia (Reynoutria spp. extract) 19.13% and 28.09% anf for ISR 2000 (Lactobacillus acidophilus fermentation product) 19.23% and 10.80% on leaves and fruits respectively. Regarding chemical fungicide, Quadris Maxx (Azoxystrobin 200 g/l+Difenoconazole 125 g/l), the effectiveness was 91.98% on leaves and 73.63% on clusters.
 Conclusion: The chemical fungicide Quadris Maxx (Azoxystrobin 200 g/l+Difenoconazole 125 g/l), used in this study provided sufficient efficacy for the disease control, while the efficacy of environmentally friendly products used was found to be quite low. However, it is very important to use of environmentally friendly products for the disease control and the further studies should be conducted.