Isolation and Control of Post-Harvest Apple Rot Pathogens Using Ginger (Zingiber officinale Roscoe.) Extracts in Mubi, Nigeria

Abstract

A survey for the rot of apple fruits sold in two markets of Mubi North Local Government, Adamawa State (Mubi Main Markets and Mubi New Markets) was conducted between June and September 2023. Also, the in vitro effect of ginger (Zingiber officinale) aqueous and ethanolic root extracts on rot control was carried out. Five fungal pathogens viz; Aspergillus niger, Ulocladium botrytis, Rhizopus stolonifer, Rhizopus microsporus, and Mucor hiemalis were identified and proven through pathogenicity test to be pathogenic. Out of the total sample size of 32 fruits (16 per market), R.stolonifer had the highest percentage incidence in both markets with 37.50 % in the main market and 31.25 % in the new market while the least was M. hiemalis (6.25 %) in the main market and   U. botrytis (6.25 %) Newmarket. Virulence of pathogens showed that R. stolonifer had very high, A. niger and R. microsporus had high while U. botrytis and M. hiemalis had moderate. Control trails on the pathogenic organisms (invitro) show that both extracts were able to inhibit the growth of pathogen with the ethanolic extract having high inhibition diameter of 0.70 cm in A. niger, 0.93 cm in U. botrytis and 0.49 cm in R. stolonifer. In comparison, aqueous had a higher mean zone of inhibition in M. hiemalis (0.63 cm) and R. microsporus (0.33 cm). There was a statistically significant difference between all the extract concentrations and the control at P≤ 0.005  It was recommended that the active components of both extracts be identified and isolated so that they can be incorporated to form fungicides that can be used commercially to control pre- and post-harvest fruit rot.