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Summary

Many strains of Plant Growth Promoting Rhizobacteria (PGPR) have the ability to induce the systemic resistance in several pathosystems. This study investigates the protective effect of four strains belonging to Bacillus subtilis (Bs168, Bs2500, Bs2504 and Bs2508) on grapevine roots of the sensitive local grapevine cultivar “Helwani” against phylloxera. Fresh roots were immersed in bacterial suspensions 0, 3, 5 and 15 hours before infesting with phylloxera eggs. Results of biometric measurements showed significant differences in the life cycle of phylloxera between treated and untreated roots. Bacillus strains negatively affected phylloxera development and reproduction. The efficiency of treatment increased when root immersion time in the bacterial suspension increased. On the other hand, there were significant differences between strains in terms of their protective effect against phylloxera, but Bs2508 strain was the most effective especially when the roots were immersed for 15 hours. This study supports previous studies in order to employing PGPR strains as biocontrol agents against pests.

Summary

Understanding pathogen-agrosystem interaction is particularly essential when applying a control method to minimize pathogen prevalence prior to plant infection. To meet this requirement, frequency of major root rot pathogens isolated from bean root and seed, and their soil populations were examined in farmers’ fields. Multivariate analyses evidenced more frequent isolations of Fusarium solani and Rhizoctonia solani from root and seed compared to Macrophomina phaseolina and Fusarium oxysporum. Two Fusarium species had denser soil populations than R. solani and M. phaseolina. More frequent isolations of pathogens were detected in root and seed collected from Abhar and Khodabandeh compared to Kheirabad region. Agronomic and soil variables corresponded less closely to root infections compared to soil infestation and seed infections. Bean market class, herbicide application, and planting depth were linked to root, seed and soil infestations. Such information provides a basis for increased confidence in choosing appropriate control strategies for a pathogen and region in sustainable agriculture.

Summary

The sugarcane whitefly, Neomaskellia andropogonis Corbett (Homoptera: Aleyrodidae), is one of the important pests of sugarcane in Iran. The use of selective chemical insecticides helps to suppress whitefly infestations. Although several insecticides from various groups have been registered to control whiteflies, this is the first study to test the efficacy of deltamethrin, dinotefuran and spiromesifen insecticides against eggs, second instar nymphs and pupae of the sugarcane whitefly on CP69-1062 sugarcane cultivar. Five concentrations of the tested insecticides were applied in a leaf dipping bioassay under laboratory conditions. Probit analysis indicated that deltamethrin and dinotefuran with LC50 values of 50.1 and 49.5 ppm were the most toxic insecticides against eggs of N. andropogonis. Deltamethrin controlled nymphal and pupal stages more effective than the other two tested insecticides and the LC50 values were 49.7 and 5.44 ppm on nymphs and pupae, respectively. The LC50 values of dinotefuran on second instar nymphs and pupae were 564.7 and 78.7 ppm and the values were 270.9 and 18.3 ppm for spiromesifen, respectively. The results support the use of the insecticides in rotation according to their different mode of action in integrated pest management programs of the sugarcane whitefly N. andropogonis.

Summary

A total of 688 bacterial endophytes were isolated from both greenhouse and field-grown tomatoes in the Tehran and Alborz provinces, Iran in order to obtain effective bacterial endophytes against the fungus Verticillium dahliae. 128 bacterial isolates, with respect to their different phenotypic characteristics were further analysed. All bacteria with positive hypersensitivity reaction on tobacco and geranium leaves and potato soft rot were eliminated, and totally 39 isolates were selected for in vitro antagonism and greenhouse tests. The potential biocontrol isolates were evaluated using seed treatment and soil drench methods on two tomato cultivars. The results indicated that seven bacterial isolates had a high potential for the control of the fungus and reduced the severity disease to 95-98%. This reduction was coincided with an increase in some growth factors like plant dry weight, root dry weight, plant height, root length, root fresh weight and plant fresh weight ranged between 92-98%. The seven antagonists’ preliminary identification was confirmed using 16SrRNA gene sequencing analysis. The BLAST analysis was performed, and the bacteria were also identified as Bacillus pumilus (two isolates), Bacillus subtilis, Bacillus safensis, Enterobacter ludwigi, Serratia marcesens and Pseudomonas beatica. Biocontrol mechanisms examination indicated that protease production was positive for all isolates and differentiated isolates E. ludwigii and P. beatica as higher producers with protease levels up to 65%. The three bacteriocins producing isolates inhibited the phytopathogenic mycelium up to 70% in dual culture assay. Also, five of the isolates produced siderophores and P. baetica, S. marcesens and E. ludwigii produced remarkable amount of auxin hormone.

Summary

The cowpea beetle, Callosobruchus maculatus (Fabricius), is recognized as a common insect pest of cowpea worldwide. The present study aimed to evaluate the insecticidal activity of ozone gas against all life stages (egg, larva, pupa and adult) of C. maculatus at a concentration of 600 ppm (1.2 g/ m3) after 6 exposure times of 0.5, 1, 2, 3, 4 and 5 h under laboratory conditions. The mortality percentages of all life stages were significantly increased with increasing exposure time. Similarly, longer exposure time to ozone caused higher reduction of adult emergence from eggs, larvae and pupae. Treatment with ozone for 5 h caused egg mortality of 72.3%. Total mortality of adults was observed 5 days after treatment with ozone for 0.5 h. Moreover, treatment with ozone for 5 h resulted in 75, 100 and 94.1% reductions in adult emergence from eggs, larvae and pupae, respectively. The results also indicated that the larvae and adults were more susceptible to ozone gas than the eggs and pupae. Based on the findings, ozone showed promising insecticidal activity against all stages of C. maculatus and could be used as potential fumigant for management of this insect.

Abstract

This study aimed to evaluate yield parameters, antioxidant activity (AOA), total polyphenol content (TPC) and total soluble solids (TSS) in beetroot cultivars with different flesh colours. Field experiments were established at the Slovak University of Agriculture in Nitra in 2016 and 2017. Within the study, 16 beetroot cultivars were tested, including 11 red-fleshed (‘Boltardy’, ‘Boro’ F1, ‘Crosby Egyptian’, ‘Cylindra’, ‘Detroit Globe’, ‘Detroit 2’, ‘Egyptian Turnip Rooted’, ‘Opolski’, ‘Pablo’ F1, ‘Renova’ and ‘Taunus’ F1), 2 yellow-fleshed (‘Boldor’ F1 and ‘Golden’), 2 white-flesh cultivars (‘Albino’ and ‘White Detroit’) and 1 red-white fleshed cultivar (‘Chioggia’). All beetroot cultivars with red flesh colour showed higher AOA and TPC than different-coloured beetroot cultivars. The highest root yield was found in the white-fleshed beetroot cultivar ‘Albino’ (37.80–41.91 t · ha−1). The highest root weight was found in the white-fleshed beetroot cultivar ‘White Detroit’ (362.4–412.1 g). The highest AOA (819.19–972.50 mg TEAC · kg−1 d.w.) and TPC (2,387.70–2,731.00 mg · kg−1 d.w.) were found in the red-fleshed beetroot cultivar ‘Pablo’ F1. Different-coloured cultivars of beetroot were characterised by a lower content of TSS (6.4–8.8 ºBRIX) than cultivars with typical, red flesh colour (7.8–10.8 ºBRIX). Results clearly indicate that cultivar, or flesh colour, is showed as a significant factor influencing the quality of beetroot. Knowing of yield potential and quality of beetroot cultivars is important for growers as well as consumers. Results of this study indicate that white-fleshed cultivars of beetroot are characterised by high yield potential but lower quality, including lower AOA, TPC and TSS.

Abstract

The aim of this study was to determine the phytochemical content of Moroccan Jujube Honey and to establish the principal components of this staple Moroccan food, which contributes health benefit for the local population. Total phytochemical compounds as determined by analytical HPLC-ESI-MS in the honey extracts were 29.39±5.21 mg/kg (range 16.64–42.16) wet weight. The individual phytochemical compounds definitively identified by HPLC-DAD-ESI-MS in the Jujube honeys were the alkaloids: (I) 4-hydroxyquinoline glucoside, (II) 4-hydroxyquinoline and (V) kynurenic acid (17.66±0.87 mg/kg), and the phenolic compounds: (III) p-hydroxybenzoic acid, (IV) caffeic acid and (VI) methyl syringate (11.73±0.50 mg/kg). The structures were confirmed by GC-EI-MS apart from 4-hydroxyquinoline-glucoside. The major components were methyl syringate (8.34±2.49 mg/kg), 4-hydroxyquinoline (6.61±3.23 mg/kg) and kynurenic acid (6.56±0.97 mg/kg). The mean content of polyphenolic compounds (11.73±0.50 mg/kg) of Moroccan Jujube honeys compared favorably with those described for six Chinese Jujube honeys (2.49 mg/kg), five commercial Jujube honeys from different countries (0.92 mg/kg) and twelve Jujube honeys from Yemen (25.71 mg/kg). Reference studies did not identify alkaloids as components of Jujube honey, and therefore the phytochemical profile of Moroccan Jujube honey appears to be unique.

Abstract

The research enabled the optimal parameters of reed stalks Phragmites australis (Cav.) Trin. ex Steud, to be determined and then be used for rearing red mason bees (Osmia rufa L.). During research conducted in 2015 and 2016, 3,293 reed stalks were occupied by red mason bees, and 19,461 nest cells were counted in the stalks, of which there were 16,222 non-parasitized larvae. The mean weight of one cocoon was 0.085 g. The mean length of the reed stalk occupied by the red mason bee was 169.45 mm, its mean diameter was 6.11 mm and the mean number of cells in the reed was 5.47. The mean length of the first cell, the vestibulum, was 38.38 mm. The mean degree of parasitism was 0.16. The length of the reed stalk positively correlated with the number of cells in the reed nest (r=0.543), vestibulum length (r=0.392) and cocoon mass (r=0.362) The diameter of the reed positively correlated with the mass of the cocoon (r=0.536), the number of cells in the reed (r=0.406) and vestibulum length (r=0.254). Correlation between degree of parasitatism and length, and diameter of the reed was insignificant. Reed stalks with a length of 150 to 200 mm and a diameter of 5–7 mm are recommended for the choice of red mason bee nesting material.

Abstract

The bacterium Melissococcus plutonius is the etiologic agent of the European foulbrood (EFB), one of the most harmful bacterial diseases that causes the larvae of bees to have an intestinal infection. Although EFB has been known for more than a century and is practically present in all countries where beekeeping is practiced, the disease has been little studied compared to American foulbrood. Recently, great advances have been made to understand the disease and the interaction between the pathogen and its host. This review summarizes the research and advances to understand the disease. First, the morphological characteristics of M. plutonius, the infection process and bacterial development in the gut of the larva are described. Also, the epidemiological distribution of EFB and factors that favor the development of the disease as well as the classification of M. plutonius according its genomic and phenotype characteristics are reported. Finally, the new molecular tools for the study of M. plutonius, possible virulence factors in its genome, the issue of current EFB control measures and possible alternatives to the use of antibiotics are addressed.