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Powdery mildew by Podosphaera xanthii (Castagne) is a major disease of greenhouse cucurbitaceous crops worldwide. Honey by honeybees has been reported as an antimicrobial for diseases in humans, animals, and plants. The aim of this study was to assess Apis mellifera honey against P. xanthii in cucumber plants. During nine consecutive weeks, four different honey concentrations (2.0%, 2.5%, 3.0% and 3.5%), a chemical control (Azoxystrobin) and an untreated check (water) were evaluated. Except for honey at 2%, every concentration was significantly different from the untreated check. Honey concentrations at 3% and 3.5% were found to be the most effective, and their area under disease progress curve (AUDP) was statistically comparable to that of Azoxystrobin with 1048.3, 642.3 and 575.8 AUDP, representing 72.4%, 83.1% and 84.8% of efficiency compared to the untreated check, respectively. These results provide preliminary information on the potential use of honey in managing strategies of the disease under greenhouse conditions., (Copyright © 2024 The Authors. Publicado por Elsevier España, S.L.U. All rights reserved.)

A potential alternative to the use of chemical products with oomyceticidal action for the control of Phytophthora capsici in vegetables is the use of antimicrobial metabolites, biosynthesized in Bacillus species. The objective of this study was to induce the biosynthesis of lipopeptides in Bacillus amyloliquefaciens KX953161.1 by using glutamic acid, iron, cellulose, chitin, or inactive Colletotrichum spp. cells. The in vitro oomyceticidal effect of the bacterial lipopeptides on zoospores of Phytophthora capsici was evaluated. The lipopeptides identified and quantified in the crude extracts by high performance thin layer chromatography (HPTLC) were fengycin and surfactin. The bacterial culture with inactive fungal cells yielded the greatest biosynthesis of lipopeptides, at 1847.02± 11.8 and 2563.45± 18.4 μg/ml of fengycin and surfactin, respectively and the treatments that obtained lower production of these lipopeptides, were those to which iron and cellulose were added with 608.05 ± 22.6 and 903.74± 22.1; 563.31± 11.9 and 936.96± 41.1 μg/ml for fengicin and surfactin, respectively. The lipopeptide extracted showed 100% germination inhibition on zoospores of P. capsici, revealing encystment, malformations in the germ tube and cellular degradation. Lipopeptides have the potential to control P. capsici; however, the biosynthesis of these lipopeptides requires further study to determine their biological mode of action and optimize lipopeptide performance and profile., (Copyright © 2022 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)