Suppression of Stem-End Rot on Avocado Fruit Using Trichoderma spp. in the Central Highlands of Kenya

View/ Open
Date
2021-03-05Author
Wanjiku, E. K.
Waceke, J. W.
Mbaka, J. N.
Metadata
Show full item recordAbstract
Demand for organic avocado fruits, together with stringent food safety standards in the global market, has made producers to use
alternative, safe, and consumer-friendly strategies of controlling the postharvest fungal disease of avocado fruits. +is study
assessed the in vitro efficacy of Trichoderma spp. (T. atroviride, T. virens, T. asperellum, and T. harzianum) against isolated
avocado stem-end rot (SER) fungal pathogens (Lasiodiplodia theobromae, Neofusicoccum parvum, Nectria pseudotrichia, and
Fusarium solani) using a dual culture technique. +e Trichoderma spp. were also evaluated singly on postharvest “Hass” avocado
fruits. Spore suspension at 5 ×104 conidial/ml of the Trichoderma spp. was applied on the avocado fruits at three time points,
twenty-four hours before the fungal pathogen (preinoculation), at the same time as the fungal pathogen (concurrent inoculation),
and 24 hours after the fungal pathogen (postinoculation). In the in vitro study, T. atroviride showed the highest mycelial growth
inhibition against N. parvum (48%), N. pseudotrichia (55%), and F. solani (32.95%), while T. harzianum had the highest mycelial
growth inhibition against L. theobromae. Trichoderma asperellum was the least effective in inhibiting the mycelial growth of all the
pathogens. Similarly, T. virens showed the highest mycelial growth inhibition against N. pseudotrichia at 45% inhibition. On
postharvest “Hass” fruits, T. atroviride showed the highest efficacy against N. parvum, N. pseudotrichia, and F. solani in all the
applications. Trichoderma virens and T. harzianum were most effective against all the pathogens during postinoculation, while
Lasiodiplodia theobromae was best controlled by T. virens, T. harzianum, and T. asperellum during postinoculation. Both
T. atroviride and T. harzianum present a potential alternative to synthetic fungicides against postharvest diseases of avocado fruits,
and further tests under field conditions to be done to validate their efficacy. +e possibility of using Trichoderma spp. in the
management of SER on avocado fruits at a commercial level should also be explored.