Two formulations containing culture filtrates and conidial suspensions of the endophytic fungus Cladosporium oxysporum Berk. & M.A. Curtis, isolated previously from stems of Euphorbia bupleuroides subsp. luteola (Kralik) Maire, were experimentally tested for their aphicid activity against the black bean aphid Aphis fabae Scop. found in Algeria. It was shown that invert emulsions are more effective against aphids, than using aqueous suspensions. This was especially true for formulations containing culture filtrates. The relatively insignificant mortalities obtained by formulations containing conidial suspensions indicated a low infectious potential towards the aphids. The proteolytic activity seemed to be more important than the chitinolytic activity of the fungus against the black bean aphid A. faba
Wheat is one of the main staple cereal crops worldwide. However, drought-induced stress is one of the factors limiting wheat productivity, especially in arid and semi-arid regions. The present study aims to investigate the influence of arbuscular mycorrhizal fungi (AMF) on wheat plant growth under water-deficit conditions. Three Algerian durum wheat varieties—Mohamed Ben Bachir (MBB), Boussellem (BS) and Waha (W)—were grown with (+AMF) or without (−AMF) under water-deficit and non-stress conditions. Morphological, physiological, and biochemical responses to AMF inoculation under water deficit were quantified. The results showed improved morphological parameters (height of the aerial part (HAP), internode length (LIN), aerial part dry weight (APDW), root dry weight (RDW), length of the ear (LE)), and chlorophyll content in AMF-inoculated plants under water-deficit conditions compared to control plants (−AMF). Moreover, soluble protein content (SPC) and membrane stability index (MSI) significantly increased with AMF inoculation under water deficit by 18% and 10%, respectively, while the proline content decreased after AMF inoculation. In addition, the water deficit significantly increases peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT), but +AMF decreases them considerably in all studied varieties. The results suggest that AMF inoculation can lead to optimized durum wheat production under arid and semi-arid conditions and provide a basis for further studies on its effects under field conditions.
The potato is a staple food crop worldwide and the need for this product has increased due to the burgeoning population. However, potato production is highly constrained by biotic stress interference, such as Myzus persicae Sulzer, which causes serious yield losses and thus minimizing production income. The current study aims to investigate the effect of different formulations prepared as an invert emulsion with different concentrations of fungal culture filtrates derived from three endophytic fungi (genus Cladosporium) against Myzus persicae. All formulations have demonstrated an aphicidal activity, which increases with the increasing concentration of fungal filtrates. Furthermore, it has been noted that chitinolytic activity recorded for 12 days is important in Cladosporium sp. BEL21 isolated from dwarf mistletoe Arceuthobium oxycedri. The study of demographic and embryonic parameters of aphids settled on potato plants previously treated with formulations revealed a significant reduction in the numbers of colonizing aphids and a relative increase in the numbers of winged adults, especially in plants treated with BEL21-derived emulsion. The pre-treatment of plants may interfere with and negatively influence embryonic development and early maturity of the embryo and thus affect the fertility of parthenogenetic aphids. BEL21-derived emulsion can ensure effective and an inexpensive control of M. persicae for potato spring cropping systems. The current results open real opportunities concerning the implementation of ecofriendly and potent potato protection systems.
The present study aims to investigate the effectiveness of bioformulations based on endophytic fungi to control apple scab and Valsa canker disease in two orchards in the Aurès region (Algeria). In both orchards, the results showed that the treatment of senescent apple leaves by invert emulsions containing Trichoderma longibrachiatum and Chaetomium globosum harmed the ascogenesis of winter forms of Venturia inaequalis by reducing the number of ascospore-ejecting asci, the number of morphologically mature asci, and a considerable increase in the immature asci number. This antifungal activity was more essential in soil-incorporated leaves, showing the importance of the combination of treatments with cultural practices to efficiently control the apple scab disease. Furthermore, the disease incidence decreased by 52.63% and 50.68% in R’haouat and Bouhmama orchards, respectively. Moreover, the treatment of Valsa ceratosperma cankers with a biogel containing the endophytic yeast Metschnikowia sp. led to wound healing varying from 43.52% and 87.97% after 120 days but remained more considerable than conventional treatment with Folicur (tebuconazol). The current results open real opportunities concerning the implementation of eco-friendly and potent apple protection systems.
Broad bean is one of the most important leguminous crops worldwide. However, its productivity is greatly affected by the infestation of Aphis fabae and Aphis craccivora (Hemiptera: Aphididae). The main objective of the current study was to identify the most susceptible phenological stages of the broad bean variety (Histal) against black aphids’ herbivory. This had been achieved through an evaluation of plant resistance mechanisms such as antixenosis and antibiosis. The results regarding an antixenosis test revealed that the four tested phenological stages of V. faba did not have a significant effect on the preference of A. craccivora and A. fabae towards the crop plant. Overall, a slightly higher number of adults settled on the three and four unfolded leaves’ stage of the crop plant. Similarly, the highest number of developed embryos were found in the four leaves’ stage of the crop, and the lowest in the second leaf stage. The adult body size of A. craccivora was slightly larger in the case of the three unfolded leaves. Furthermore, the maximum body size of A. fabae adults was recorded in the case of the first unfolded leaf stage crop. Linear correlations between the biological parameters for both species revealed only one significant relationship between developed and total embryos for A. craccivora. The results of the current study highlight the need to protect broad bean crops against infestations of black aphids, i.e., A. craccivora and A. fabae. This is essential for reducing direct damage and preventing the transmission of phytoviruses. However, future studies should aim to evaluate the susceptibility of all developmental phenological stages of the crop against black aphids to mitigate potential crop losses.