Effect of Mixed Infections of Potato Plants by Different Fusarium Species on Fusarium wilt Severity Plant Growth, and Tuber Yield

Objectives Fusarium wilt of potato has become increasingly widespread in many potato-growing regions and was caused by F. sambucinum , F. oxysporum , F. solani and F. graminearum . This fungal complex can occur within the same potato plant. Cultivar’s reaction to different mixtures can give additional information on their relative aggressiveness. This study may lead to a better understanding of how interactions between the four Fusarium species may affect disease incidence and severity. Methods interactions between these Fusarium species was evaluated using single and mixed infection (15 Fusraium inoula) onto two local potato cultivars (Spunta and Oceania). The different mixtures of Fusarium species were tested on potato plants to evaluate their Necrosis and Vascular browning severity and their effect on potato growth and production parameters compared to individually inoculated species. Result data indicated that the necrosis severity noted 75 days post-planting induced by C2-1 ( F. sambucinum + F. solani ) and C2-2 ( F. solani + F. oxysporum ) and C3-3 ( F. sambuinum+F. oxysporum +F. graminearum ) were found to be the highly aggressive inoculation treatments. Overall, all mixed inoculums including F. sambucinum showed increased aggressiveness levels. The two cultivars exhibited differential response to the different Fusarium mixtures tested. Both tested cultivars behaved in the majority as sensitive to moderately sensitive to C1-1, C1- 4, C2-1, C2-2, C2-3, C2-4, C2-5, C2-6, C3-1, C3-3, C3-4 and C4 infections. Conclusion this study clearly indicate that that disease development and severity of Fusarium wilt is expected to be more augmented when more than one Fusarium species were present. The relative predominance of F. sambucinum may reflect their competitive potential in mixture and their relative involvement in potato Fusarium wilt severity.