Efficacy of Bioagents Against Fusarium Wilt of Guava

摘要

Eight isolates of bioagents, comprising Aspergillus niger (AN1, AN6 and AN9), Trichoderma spp. (T. virens, T. harzianum and T. viride) and Penicillium citrinum (P1 and P2), their culture filtrates and volatile compounds were tested against five isolates each of Fusarium oxysporum f. sp. psidii and F. solani that caused guava wilt. All bioagents significantly checked the growth of F. oxysporum f. sp. psidii and F. solani. The inhibition was high with the direct use of Trichoderma spp. in dual cultureagainst F. oxysporum f. sp. psidii (61-69%) and F. solani (58-68%). A. niger also expressed a moderate efficacy (39-60%) against both pathogens. However, P. citrinum isolate showed less control. Overall, T. virens and T. viride were superior in inhibiting the growth of both species of Fusarium. But, Fusarium isolates showed intra-species variability. Based on in vitro performance, isolates of Trichoderma (Tvd-P) and Aspergillus (AN9) were evaluated in fields. During the three years tested, guava wilt disease was low in incidence (5%) while the two bioagents completely suppressed wilt. However, bioagents showed plant growth promoting effect on guava plants.