- 期刊
- OpenAccess
Sensitivity of Progeny of Phytophthora infestans to Fungicides
並列摘要
This study investigated fungicide sensitivity of progeny of Phytophthora infestans at the University of Wales, Bangor. Sexual progeny were derived from an A2 parent that was Metalaxyl Sensitive (MS) with three A1 parents that were: MS, MS and MR (metalaxyl resistant). Sporangial and zoosporangial progeny from the parent and from some sexual progeny were also assessed. The different isolates were grown on Rye B Agar amended with different concentrations of one of five different fungicides: Metalaxyl, Propamocarb hydrochloride, Cymoxanil, Fluazinam and Azoxystrobin. The results indicated that in metalaxyl, the sensitivity of sporangial progeny was similar to that of the parent isolates, however that of zoosporangial progeny ranged from being Intermediate (MI) to being Resistant (MR) if the parents were Resistant (MR) or from Sensitive (MS) to being Intermediate (MI) if the parents were Sensitive (MS). No resistance was observed among progeny that were exposed to Azoxystrobin. With the other fungicides, there was a variation in the sensitivity of sporangial and zoosporangial progeny e.g. some sensitive sporangia gave rise to highly resistant zoospores. The results showed that resistance to the most commonly used fungicides against late blight is possible. Although no resistance to the new fungicide azoxystrobin was observed, the appearance of resistance to it among other fungal pathogens has been reported. Therefore, breeders are faced with a challenge of coming up with cultivars with reduced susceptibility to late blight and plant pathologists are to come up with a wide range of fungicides so that their use can be rotated to avoid build-up of resistance isolates.