Identification of the Pathogens and Laboratory Bioactivity Determination of the Rot Disease of Kiwifruit (Actinidia spp.)

Kiwifruit is an important economic crop in the world today with a high nutritional value. It can cause huge damage by causing kiwifruit rot disease; however, at present, the control methods for this disease are limited. In this study, the rotten fruits of kiwifruit (Cultivar "Jinyan") were collected from Pujiang city (Sichuan province), Xixia city, (Henan province), Zhouzhi (Shaanxi province), Meixian city (Shaanxi province), and Bijie (Guizhou province), China, and the pathogenic fungi were identified by isolation and purification, pathogenicity test, morphological characteristics, and analysis of ribosomal DNA internal transcribed spacer (rDNA-ITS) sequences. The results showed that the pathogenic fungi of kiwifruit rot disease were Botryosphaeria dothidea and Dothiorella gregaria. Meanwhile, the in vitro antifungal activity of 11 kinds of fungicides and 5 kinds of plant essential oils against B. dothidea and D. gregaria were determined and the results showed that all the tested fungicides and plant essential oils had a certain inhibitory effect on B. dothidea and D. gregaria. Among them, propiconazole had the best inhibitory effect on B. dothidea with an EC50 value of 4.10 mg/L, and quinolinone had the best inhibitory effect on D. gregaria with the EC50 value of 10.05 mg/L. Moreover, the pesticides and essential oils have practical application values for prevention and treatment of fruit rot diseases pathogens.