Keywords: Pseudomonas savastanoi pv. savastanoi, olive knot disease, biological control, antagonistic bacteria, Bacillus subtilis 1240, Shimadzu) at 600 nm (El-kinany et al., 2017). Antagonistic strainsAll antagonistic strains belong to the collection of laboratory of plant bacteriology and Biological Control at the National Institute of Agronomic Research (Meknes, Morocco). Theirs origins, isolation dates, and references are described in Tab 1.Olive knot disease caused by Pseudomonas savastanoi pv. savastanoi (PSS) is considered as the main bacterial disease of olive tree in Morocco. However, sole prophylactic measures are available. The main aim of this work was to evaluate the effects of eighteen antagonistic bacteria, as an alternative approach, to control in vitro and in planta the pathogens strains previously isolated from olive trees in Morocco. In vitro experiments revealed that many bacterial strains such as Rahnella aquatilis, Enterobacter ludwiqii, Paenibacillus brasiliensis, and Bacillus subtilis selected from collection of Regional Center of Agronomic Research, were efficient on solid media against pathogen strains. Their inhibition zones ranged from 8 to 23 mm with a higher inhibition rates found by B. subtilis strains. Enzymatic activities of antagonistic strains were assessed (cellulase, protease and amylase) as well as some plant growth promotion traits (phosphorus solubilisation and indole acetic acid production) for performance screening. B. subtilis 2515-1 was selected for pots experiment using olive trees (cv. Arbequina). This bacterium significantly reduced number and weight of knots against two pathogens strains (PSS 2064-8 and PSS 2102-4). The most reduction rates of weight and knot number were respectively 95.60% and 50%. This study suggested an alternative approach to assess the efficiency of selected bacterium in field conditions. ARTICLE INFO

Stored grains are threatened by several insects, leading to losses in quality and quantity. Several studies have revealed the risks of using chemicals that can cause serious health problems for humans. It is in this perspective that the objective of our work should be seen: It was to assess the effect of the essential oil and leaf powder of Mentha pulegium against Sitophilus oryzae and Tribolium castaneum adults attacking post-harvest cereals. The insecticidal activity of the essential oil against these two insects was evaluated by three methods: contact, inhalation and ingestion. The ingestion method was used in the case of the leaf powder. The essential oil and leaf powder of Mentha pulegium exhibited insecticidal activity against Sitophilus oryzae and Tribolium castaneum adults (Mentha pulegium essential oil caused up to 100% mortality of both insects). Both insects were influenced affected by the dose, exposure time and the method by which the insecticidal activity of the essential oil was demonstrated. Adults of Sitophilus oryzae were more sensitive to different concentrations of essential oil and leaf powder than those of Tribolium castaneum. The essential oil has no effect on the germination rate of soft wheat grains (Triticum aestivum). On the contrary, it acts positively by reducing the damage caused by these major stock pests. The data from this study could present an alternative solution for replacing synthetic insecticides for the protection of stored commodities.

This research was conducted to evaluate the components of the Mentha pulegium (L) and Glycyrrhiza foetida (Desf) that were extracted by hydro distillation and analyzed using GC-MS methods. They are spontaneous plants widespread in Gharb of Morocco. The aim of the study is to investigate the antibacterial activity of the essential oils and leaf methanolic extracts of these two medicinal plants against five phytopathogenic bacteria. The evaluation of the antimicrobial activity of the two species by estimating the diameter of the inhibition zone has shown that the essential oil of M. pulegium exhibited a higher antimicrobial activity than G. foetida which varied according to the sensitivity of the phytopathogenic strains. The results obtained revealed different degrees of sensitivity toward methnolic extract. However, the methanolic extract and the essential oil of M. pulegium are more active based on the Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC). The antimicrobial activities of leaf extracts from the two plants highlighted in this study could justify their therapeutic use. These results should be strongly recommended as an alternative to a chemical compound that still represents the problem of toxic residues.

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