Identification and control of associated mycoflora of sweet orange (Citrus sinensis) fruit rots in Ibadan, Oyo state Nigeria

Abstract

A laboratory trial was conducted to identify pathogens associated with sweet orange (Citrus sinensis) fruit rots and to test the efficacies of some fungicides against the isolated organisms in vitro and on infected fruits. Five fungal species; Botryodiplodiathreobroma, Alternariaalternata, Fusarium spp, Aspergillusniger and A.flavus were isolated in this study as rot pathogens of sweet orange. All isolates except Fusarium spp. were capable of inducing rot in artificially inoculated fruits. The extent of rot induced by B. threobroma and A. jlavus were severe with more than 75% of the fruits damaged. Alternariaalternata and Aspergilusniger induced rot ranging between 25-50%. Carbendazin had total inhibitory effect (100%) on mycelia growth of A. flavus, A. niger, B. theobroma and A. alternata in vitro while mancozeb had percentage mycelial inhibition of 84.29, 90.8, 90.8, and 55.9 % on B. theobroma, A. alternata, A. jlavus and A. niger respectively. However, there were no significant differences in mycelia inhibition induced by maneb on all the pathogens except on B. threobroma where it showed less activity. While carbendazin effectively control the rot induced by all the pathogens tested mancozeb did not provide total control on rots induced by A. niger and A. jlavus with rot diameters of 13.33 and 25.00mm. Results of this study showed that carbendazin had the highest inhibitory effects on all the rot pathogens in vitro and in vivo and can therefore be effectively used in the control of sweet orange fruit rots.