Search

Background: Spodoptera littoralis is an important agricultural pest; thus, knowledge about the effect of latex serum and latex-synthesized nanoparticles of Calotropis procera on this species can assist in its management.. Nanotechnology is currently taking root in the agriculture economy as a substitute for pest management that is targeted, safe, and effective. The repellent and antifeedant efficacy of C. procera latex serum and its nanoparticles against S. littoralis fourth instar larvae was investigated in this work. Methods: The process of synthesizing silver nanoparticles has been carried out, followed by their subsequent characterization. The objective of this study was to assess the antifeedant properties of the latex serum and its nanoparticles against the 4th instar larvae of S. littoralis through the implementation of a bioassay. Results: With rising latex serum content, the proportion of repellency and hunger rose. In comparison to insects injected with latex serum, utilizing nanoparticles of LAgNPs with this larva via injection resulted in much increased mortality. Conclusion: According to the findings of this study, insects injected with LAgNPs died at a substantially higher rate than insects injected with latex serum. LAgNPs was efficient against S. littoralis larvae and can thus be utilized to specifically control the pest. [ABSTRACT FROM AUTHOR]

The fungal biodiversity in 30 samples, 10 of each of peanut seeds, corn and wheat grains were estimated on two isolation media (AFPA and DRBC). The aflatoxigenic ability of isolates related to Aspergillus section Flavi using CAM agar plates was also assessed. The results indicated that the mean moisture content was relatively low in peanut (8.05%) while it was relatively high in corn samples (10.45%). A limited number of peanut seeds but a large number of corn grains were fungi-free on both media. On AFPA, the aflatoxigenic species contaminated 9, 5 and 7 of peanut, corn and wheat samples respectively. On AFPA and DRBC, the total number of genera and species recorded on wheat were higher than those on corn and peanut and only three genera, Aspergillus, Penicillium and Fusarium were isolated from the three substrates. Aspergillus possessed more propagules on peanut than on corn and wheat, whereas Fusarium and Penicillium had more propagules on corn than on peanut and wheat. The aflatoxigenic species A. flavus, and A. niger were isolated from the three substrates. These two species showed higher propagules on peanut and corn than on wheat. P. chrysogenum, P. duclauxii and F. verticillioides were recorded from corn and wheat grains, P. aurantiogriseum and F. chalamydosporum from corn and P. brevicompactum, P. funiculosum from wheat and P. pinophilum and F. oxysporum from peanut only. Flourescence at 365 nm of 43 A. flavus and other 4 fungal strains recovered from the analyzed substrates and grown on CAM agar plates revealed that all A. flavus strains showed blue color with different intensities indicating aflatoxin B production, while the other 4 non-A. flavus strains showed negative results. [ABSTRACT FROM AUTHOR]

Chemical profile of Monascus ruber strains has been studied using gas chromatography--mass spectrometry (GC/MS) analysis. The colour intensity of the red pigment and secondary metabolic products of two M. ruber strains (AUMC 4066 and AUMC 5705) cultivated on ten different media were also studied. Metabolic products can be classified into four categories: anticholesterol, anticancer, food colouring, and essential fatty acids necessary for human health. Using GC/MS, the following 88 metabolic products were detected: butyric acid and its derivatives (25 products), other fatty acids and their derivatives (19 products), pyran and its derivatives (22 products) and other metabolites (22 products). Among these, 32 metabolites were specific for AUMC 4066 strain and 34 for AUMC 5705 strain, whereas 22 metabolites were produced by both strains on different tested substrates. Production of some metabolites depended on the substrate used. High number of metabolites was recorded in the red pigment extract obtained by both strains grown on malt broth and malt agar. Also, 42 aroma compounds were recorded (4 alcohols, 2 benzaldehydes, 27 esters, 3 lactones, 1 phenol, 1 terpenoid, 3 thiol compounds and acetate-3-mercapto butyric acid). Thin layer chromatography and GC/MS analyses revealed no mycotoxin citrinin in any media used for the growth of the two M. ruber strains. [ABSTRACT FROM AUTHOR]

A total of 34 species belonging to 21 genera of fungi were recorded on passion fruits of both pure and hybrid origin in Uganda, however, the pure type exhibited wider spectrum (28 species and 16 genera) than the hybrid type (21 & 15). Also, yeasts (unidentified and Rhodotorula mucilaginosa) were also encountered in high numbers. Moreover, the mean count of all mycobiota obtained from the pure type was higher than that of hybrid, despite the bigger size of the later. Members of yeasts and Cladosporium followed by Phoma, Penicillium, Fusarium and Alternaria species dominated on passion fruits of pure origin, while only C. cladosporioides, F. solani and yeasts dominated on the hybrid type. Treatment with Na-hypochlorite exhibited inhibitory effects on the total mycobiotic propagules as well as the dominant species from fruits of both types. The current results, therefore, suggest the use of Na-hypochlorite to control the post-harvest mycobiota associated with passion fruits. Regarding the mycobiota contaminating passion juice, yeasts were found to be the major contaminants with Candida parapsilosis being the most common. Moulds constituted only a minor proportion with Acremonium strictum followed by Fusarium chlamydosporum, F. moniliforme, F. acuminatum and F. solani as the most dominant species. In the heat-treated juice samples, the counts of the most commonly encountered mycobiota (both yeasts and molds) were significantly inhibited or completely eliminated. Some unidentified Bacillus species were also recovered from the juice, however, their counts in the heated samples were increased but insignificantly.