V. V. Vasilchenko1, T. S. Bibik2, A. N. Smirnov1
1Russian State Agrarian University – Moscow Timiryazev Agricultural Academy, ul. Timiryazevskaya, 49, Moskva, 127550, Russian Federation
2Vladimir Agricultural Research Institute, ul. Tsentral’naya, pos. Novyi, Suzdal’skiir-n, Vladimirskaya obl., 3601261, Russian Federation
Abstract. We examined the aggressiveness manifestation of isolate 161 of Phytophthora infestans (Mont.) de Bary) and isolate 10 of Alternaria alternata (Fr.) Keissl.) at potato tuber slices of cultivars Zhukovsky Ranny (“Zhukovsky Early”), Udacha (“Luck”), Red Scarlett, Avrora (“Aurora”). The experiments were carried out at the temperature of 20–22 Celsius degrees, moderate light and air humidity of 75%. The replication was four-fold. A composite aggressiveness index (CAI) was calculated: CAI = (LA x SC) / (IP x LP), where LA is a lesion area, SC is sporulation capacity, IP is an incubation period, LP is a latent period. CAI data were processed by means of the three-factor variance analysis. Factor А was cultivars; factor B was a type of infection (P. infestans zoosporangia and zoospores, A. alternata conidia, mixture of P. infestans zoospores and zoosporangia with A. alternata conidia); factor С was infection load (the initial concentration (A. alternata – 20,000 conidia/mL, P. infestans – 10,000 zoosporangia/mL), its dilutions 2, 4, 8, 16 times). The influence of all factors was significant; factor C was the most influential. The variants had insufficient differences in the degree of injury. Tuber slices of Zhukovsky Ranny and Avrora varieties were stronger affected with A. alternate; Udacha and Red Scarlett varieties were injured by both A. alternata and P. infestans. The greatest CAI (0.267) was observed at inoculation of tuber slices of Avrora cultivar with A. alternate in the highest concentration. The greatest CAI (0.141) for P. infestans was observed for Red Scarlett variety in the case of 2 times zoosporangia dilution. The decrease of CAI was observed at a dilution of inoculum. CAI on the mixture of pathogens was lower than that of the separate pathogens. This is the evidence of competition between P. infestans and A. alternata on host plant tissues. Synergism was manifested only at minimal inoculum on Udacha and Red Scarlett cultivars: CAI of the pathogen mixture was higher (up to 0.042) than CAI of separate pathogens (up to 0.012).
Keywords: Phytophthora infestans; Alternaria alternata; potato late blight; potato early blight; aggressiveness; short-termed viability of potato pathogens.
Author Details: V. V. Vasilchenko, post graduate student (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.); T. S. Bibik, Cand. Sc. (Agr.), head of division; A. N. Smirnov, prof. (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.).
For citation: Vasilchenko V. V., Bibik T. S., Smirnov A. N. Comparison of Aggressiveness of Phytophthora infestans and Alternaria alternata at Tuber Discs of Different Potato Cultivars . Dostizheniya nauki i tekhniki APK. 2018. Vol. 32. No. 10. Pp. 24–27 (in Russ.). DOI: 10.24411/0235-2451-2018-11005.