Abstract:

Effect of p-hydroxybenzoic acid esters on black spot and soft rot diseases of postharvest apricot fruits was studied
using in vitro and in vivo tests. The results of in vitro test showed that p-hydroxybenzoic acid esters significantly inhibited the
colony growth of Rhizopus stolonifer and Alternaria alternata. Ethyl 4-hydroxy benzoate and butyl paraben had better effect
in a concentration-dependent manner. Butyl paraben, when use at a dose of 100 μL/L, was more effective against the two
pathogens with antifungal rates of 23.70% and 62.48%, respectively. The inhibitory effect of p-hydroxybenzoic acid esters
on Rhizopus stolonifer was better. In vivo test showed that p-hydroxybenzoic acid esters could effectively control black spot
and soft rot diseases of apricot fruits inoculated with R. stolonifer and A. alternata. p-Hydroxyl benzoate was more effective
against soft rot disease, and the development of black spot disease was significantly reduced by ethyl 4-hydroxybenzoate
treatment at a dose of 240 μL/L. The optimum treatment conditions for postharvest disease control of apricot fruits were
determined through orthogonal array design as 32 μL/L propyl p-hydroxyl benzoate combined with soaking in 50 ℃ water
for 7 min. Verification results showed that the inhibition rates of the optimal treatment against black spot and soft rot disease
reached 32.22% and 51.84%, respectively.

Key words: p-hydroxyl benzoate, apricot fruit, Alternaria alternata, Rhizopus stolonifer, disease control