This work investigates an experimental study for using low-cost and eco-friendly oils to increase the shelf life of strawberry fruit. Three natural oils were used: (i) Eucalyptus camaldulensis var obtuse, (ii) Mentha piperita green aerial parts essential oils (EOs), and (iii) Moringa oleifera seeds n-hexane fixed oil (FO). Furthermore, a mixture of EOs from E. camaldulensis var obtusa and M. piperita (1/1 v/v) was used. The treated fruits were stored at 5 °C and 90% relative humidity (RH) for 18 days. HPLC was used to analyse the changes in phenolic compounds during the storage periods. The effects of biofumigation through a slow-release diffuser of EOs (E. camaldulensis var obtusa and M. piperita), or by coating with M. oleifera FO, were evaluated in terms of control of post-harvest visual and chemical quality of strawberry fruits. The post-harvest resistance of strawberry fruits to Botrytis cinerea fungal infection was also evaluated. As a result, the EO treatments significantly reduced the change in visual and chemical quality of strawberry fruit. Additionally, changes in the titratable acidity of moringa FO-coated strawberry fruits were delayed. EO treatments improved total soluble solids, total phenols, ascorbic acid, antioxidants and peroxidase. E. camaldulensis var obtusa and M. piperita (1/1 v/v) EO-vapour fruit exhibited a slower rate of deterioration, compared to other treatments in all tested, in two experiments. The lowest colour change (ΔE) was observed inthe fruit treated with E. camaldulensis var obtusa EO and M. oleifera FO. HPLC showed changes in phenolic compounds’ concentration, where p-coumaric acid, caffeic acid, gallic acid, ferulic acid and ellagic acid were mostly identified in the fruits treated with the oils. SEM examination confirmed the potential decrease in fungal growth as the fruits were treated with EOs. In conclusion, the treatment of EOs during different storage periods showed promising characterisations for strawberry fruit quality.

In the present study, growth and productivity of hot pepper planted in the two successive summer seasons of 2017 and 2018 were evaluated under the effect of foliar spray of variable doses of potassium silicate (PS), and clove water extract (CWE) with different rates of nitrogen (N) fertilization application. The post-harvest resistance of hot pepper fruits to Alternaria alternata fungal infection, was also evaluated. Maximum plant height was achieved with the application of the highest rates of N, PS and CWE, while the intermediate rates were sufficient to reach the maximum number of branches, the highest leaf dry matter and chlorophyll accumulation. Fruit yield progressively increased with increasing the applied N rate. The foliar application of PS and CWE exerted a limited, yet positive effect on fruit yield. Generally, the least amount of fruit yield, amounting to 18.84 and 18.00 t ha⁻¹, resulted from the application of the lowest N rate (144 kg ha⁻¹) in the absence of PS and CWE. The highest significant fruit yield, amounting to 31.71 and 31.22 t ha⁻¹, for 2017 and 2018, respectively, accompanied the application of the maximum levels of the three factors. The application of high N rates increased the post-harvest Alternaria fruit rot severity. The positive effect of CWE application in counterbalancing the negative effects associated with the high rates of N and PS may be related to the presence of phenolic and flavonoid compounds ellagic acid, benzoic acid, catechol gallic acid, rutin, myricetin, quercetin, apigenin and kaempferol as identified by High Performance Liquid Chromatography (HPLC).

The antifungal effect of Chlorella vulgaris extract (CVE) against potato pathogen, Rhizoctonia solani was evaluated in vitro and in the greenhouse. Methanolic extract of C. vulgaris exerted significant effects on the growth of the pathogenic fungi, either by inhibiting fungal mycelia growth in solid and liquid media or the formation of infection cushion, that was observed by light microscope. The inhibitory effect on the fungal growth increased as the concentration of algal extract increased. Disease resistance was assessed in the greenhouse against Rhizoctonia black scurf using drench application of CVE. The application of CVE significantly reduced disease severity and improved the quality and quantity of potato tubers yield. The chemical composition of the methanolic crude extract of C. vulgaris was analyzed by GC-MS. Palmitic and oleic acids, glycine and phenol were among the major compounds found in the methanolic crude extract which exhibited variable efficiency against the pathogen in vitro. The microalgae C. vulgaris extract demonstrated great potential to be commercialized as a natural product against R. solani on potato crops.

Les objectifs de cette étude étaient de déterminer la production qualitative des enzymes extracellulaires de dix champignons endophytes et d’étudier le potentiel antimicrobien de leurs filtrats sur certains champignons phyto-pathogènes. Les dosages enzymatiques ont démontré qu’il y avait une variation dans la production de différentes enzymes extracellulaires parmi les champignons endophytes testés. Tous les champignons endophytes étaient capables de produire des protéases et de la cellulase avec des niveaux différents sauf Alternaria alternata. Pourtant, les espèces Fusarium, Alternaria, Nigrospora et Phoma étaient capables de produire l’amylase. Aucun des champignons endophytes testés n’a produit de laccase. Les filtrats de champignons endophytes ont révélé des activités antifongiques variables contre les champignons phytopathogènes testés, dont le plus efficace était le filtrat de Curvularia lunata. Ce filtrat a induit une inhibition de croissance de 48 % et 80 % de Botrytis cinerea et Rhizoctonia solani respectivement. L’analyse phytochimique de l’extrait brut de champignons endophytes a révélé la présence d’alcaloïdes et de terpénoïdes. Les observations morphologiques au microscope optique ont montré une déformation hypale et un élargissement des vacuoles cytoplasmiques de R. solani lorsqu’il est traité avec du filtrat de C. lunata. De plus, C. lunata (suspension d’hypales et filtrat) a été examiné pour lutter contre la pourriture des racines causée par R. solani sur des plants de fèves in vivo. Les deux traitements antagonistes ont considérablement réduit la gravité de la pourriture des racines.

Resistance Marker Detection in Ten Date Palm Cultivars to the Wilt Pathogen, Fusarium oxysporum