Integrated application programmes for jujube black spot management: Effects on defence-related enzyme activities and fruit quality

Jujube black spot disease, mainly associated with Alternaria alternata , threatens fruit marketability and quality in major production areas of Xinjiang, China. This study evaluated whether stage-specific integration of resistance inducers, biocontrol agents, and fungicides could improve disease suppression while maintaining fruit quality. Individual and mixed treatments were screened in a randomised complete block experiment, and selected programmes were applied at flowering, fruit expansion, white-ripe, and full-ripe stages. Field efficacy, defence-enzyme activity, estimated yield, fruit quality, and pesticide input cost were assessed. Resistance inducers and mixtures produced distinct temporal defence responses; disease control and estimated yield did not always vary in parallel. Among individual treatments, amino-oligosaccharide combined disease suppression, estimated yield, and defence activation. The stage-specific A-MPT programme—two early amino-oligosaccharide applications followed by two applications of polyoxin plus tebuconazole—maintained disease control and produced a favourable sugar–acid profile. Entropy-weighted technique for order preference by similarity to ideal solution (TOPSIS) analysis ranked A-MPT as the most balanced programme across disease-control, quality, estimated-yield, and pesticide-cost indicators. These findings support stage-specific integration of resistance induction and later direct pathogen suppression as a promising strategy for jujube black spot management. Multi-season and multi-site validation, direct measurement of marketable yield, and full cost–benefit analysis are needed before broad commercial recommendation.