Isolation and Characterization of Contaminant Mycoflora from Stored Red Peppers

Red pepper is a spice vulnerable to fungal growth and mycotoxin contamination while in the field and post-harvest during storage. Storage fungi are omnipresent and colonize fast when moisture levels go up, ultimately leading to mycotoxin production. Stored samples of the whole, crushed and ground red pepper in the Southern Indian States and Maharashtra, India were examined to isolate and characterize the prevalent contaminant fungal species. The average moisture content was below 10% for all the red pepper samples and the average total fungal load was less than 1×104 CFU/g. Crushed red pepper showed higher fungal counts than ground and whole red pepper. The identified contaminant mycoflora belonged to the group; Aspergillus, Eurotium sp., Cladosporium sp., Eupenicillium sp., Penicillium sp., Miscellaneous fungi, Neosartorya sp., Curvularia sp., and Hyphopichia sp. Aflatoxigenic Aspergillus flavus was present only in 8.3% of the crushed and 2.54% of whole red pepper samples stored for more than two months.

Effect of Eggplant Root Extracts on the Growth of Storage Fungi of Wheat Grains and Their Ability for Aflatoxin Production in Babylon Silos in Iraq

Kadhim, I.J., F.H. Kareem and S.H. Segar. 2021. Effect of Eggplant Root Extracts on the Growth of Storage Fungi of Wheat Grains and Their Ability for Aflatoxin Production in Babylon Silos in Iraq. Arab Journal of Plant Protection, 39(1): 29-38. Seed-borne fungi adversely affect seed germination and seedling vigor and results in economic loss to farmers. In the present study, the antifungal activity of aqueous and alcohol extracts from eggplant (Solanum melongena L.) roots against fungi isolated from local wheat grains stored in the old Hilla silo and the new Hilla silo in Babylon, Iraq were investigated during the growing season 2017-2018 by using the poisoned food technique. The ability of the isolated fungal species for aflatoxins production was assayed. The results obtained showed that the aqueous extract contained flavonoids, whereas the alcohol extract contained flavonoids and alkaloids. Three fungal species associated with stored wheat grains were isolated, namely: Aspergillus niger, Penicillium notatum and Fusarium oxysporum. It was found that the extracts had a significant inhibitory effect on the growth of these fungi grown on potato dextrose agar medium compared with the control at P=0.05. At a concentration 36 مجلة وقاية النبات العربية، مجلد 39 ،عدد 1( 2021 ) of 10 mg/ml, the alcohol extract had a significantly higher inhibition rate which reached 91.11, 88.88 and 91.11%, on the three fungi, respectively, as compared to 86.66, 86.66 and 83.33% for the aqueous extract, respectively. The results also showed that Aspergillus niger and Penicillium notatum were able to produce aflatoxins. Keywords: Aflatoxins, alcohol extract, aqueous extract, flavonoids.

Effect of chemical treatment on the physiological and sanitary quality of stored coffee seeds

Maintaining the health of coffee seeds is especially important during storage, as soil fungi and storage fungi can considerably reduce seed quality. Thus, chemical treatments for protection of seeds in storage becomes important in agricultural production. It is necessary to evaluate the effects of these treatments on seedling development and the protection they provide against storage fungi, aiming at seed longevity and preventing rapid deterioration. The aim of this study was to evaluate the effect of chemical treatment on the physiological and sanitary quality of stored coffee seeds. Seeds of five Coffea arabica cultivars were pre-dried, treated with Vitavax®-Thiram, and placed in cold storage at 10 °C for nine months. Seed physiological quality was evaluated every three months by the germination test and by determination of root emergence percentage, seedlings with expanded cotyledonary leaves, and seedling dry matter. Seed health quality was assessed by the health test. The chemical treatment with Vitavax-Thiram does not affect the physiological quality of stored Coffea arabica seeds. Seed treatment before storage is effective in reducing the inoculum potential of Fusarium spp. and Phoma spp. in coffee seeds.

Application of the Best Techniques to Reduce the Percentage of Storage Fungi in Peanut Seeds Arachis hypogaea

This study was conducted during the season 2019-2020 with the aim of testing the efficiency of some techniques to eliminate or reduce the frequency of storage fungi, namely Aspergillus flavus, A. niger, and Penicillium italicum naturally contaminating peanuts seeds. The seed sample was treated by soaking in hot water (50˚c, 60˚c, 70˚c), soaking in salt water at concentrations 10%, 15%, 20%, roasting in an ordinary oven at 150˚c for 10, 20 and 30 min, and roasting in a microwave oven at 100˚c for 1, 3, 5 and 7 min. The frequency of fungi occurrence percentage was estimated in seeds after treatments and incubation on the nutrient medium Potato Sucrose Agar (PSA). The results indicated the efficiency of all the techniques used in reducing the frequency of fungi in the treated seeds, as the fungus P. italicum was the most sensitive fungus under all techniques, and the study proved the superiority of the treatment by microwave roasting over the rest of the techniques, as it eliminated all the fungi carried in the seed by 100% when the duration of time used is 5 minutes.

Vapour-phase efficacy of selected essential oils individually and in combination against Aspergillus flavus, A. niger, Fusarium proliferatum, and Curvularia lunata

Grain storage plays a crucial role in ensuring food security to Thai farmers so sustainable protection methods against deleterious microorganisms, such as fungi, are necessary. Essential oils (EOs) have demonstrated broad-spectrum fumigant antifungal activity against most storage fungi that are problematic in Thailand. Four storage fungi (Aspergillus flavus, A. niger, Curvularia lunata and Fusarium proliferatum) were isolated from dried rice and corn grains (stored for at least six months). EOs were extracted by hydrodistillation from clove buds (Syzygium aromaticum), fruit peel and leaves of makrut lime (Citrus hystrix), eucalyptus leaves (Eucalyptus sp.) and lemongrass stems (Cymbopogon citratus). The fungi inoculated on PDA in plastic cups were exposed to each EO vapour originating from paper disc attached in the lids in an inverted position. The minimum inhibitory concentration (MIC) for each EO was determined. Selected MICs were combined in a binary manner and similarly tested against the fungi. Fractional inhibitory concentration indices (FICI) were determined for each combination. Lemongrass and makrut lime leaf EOs were the most effective with MICs of 0.09 µL/mL against Curvularia lunata and 0.19-0.28 µL/mL against A. flavus, A. niger and F. proliferatum. Eucalyptus oil produced the least effective vapour (MIC 0.56-0.74 µL/mL) against all tested pathogens. A combination of lemongrass and makrut lime leaf EOs was partially synergistic against A. niger (FICI=0.75) but was fully synergistic against the other three fungi tested (FICI=0.5). The EOs from lemongrass and makrut lime leaf have potential to suppress the growth of the four grain-storage fungi tested.

Phytosanitary Quality of Genotypes of Wheat Seeds Used Northern Paraná State

Wheat seeds can be infested and/or infected by microorganisms that might cause deterioration of this propagation structure. The aim of this study was to evaluate the health quality of sixteen wheat genotypes grown in northern Paraná. Therefore, seeds of each genotype were submitted to the blotter test with 16 repetitions, 400 seeds per sample, for phytosanitary quality evaluation. The identification of the fungi was performed based on their morphological characteristics and quantified data. The results revealed variations in incidence, with 20 fungi genera in the analyzed samples. The fungi Rhizopus sp., Aspergillus sp., Penicillium sp. and Bipolaris sp. were found in 100% of the analyzed samples, while Mucor sp. and Alternaria sp. were in 89% and 78% of the samples, respectively. The main pathogens that cause diseases in the aerial part of wheat were not found, or were low incidence in all materials analyzed. The pathogens with the highest incidence associated with wheat seeds were groups of storage fungi and known to produce mycotoxins.

Study of the Control of Fungus Occurring in Schizolobium amazonicum Seeds with the Use of Pyroligneous Extract

Fungi are the main microorganisms present in seeds, constituting the main cause of deterioration and production losses. Among the health testing methodologies for detecting fungi in seeds, incubation tests under controlled conditions facilitate fungal growth and sporulation. Therefore, this work aimed to evaluate the efficiency of pyroligneous extract in the control of phytopathogenic fungi occurring in Schizolobium amazonicum seeds. Treatments consisted of exposure of seeds to pyroligneous extract for a period of five minutes at concentrations (0%, 1%, 2.5%, 5%, 7%, 10% and 12.5%). The treated seeds were placed in Petri dishes, lined with two sheets of filter paper, moistened with sterile distilled water. The experimental design was completely randomized, consisting of 7 treatments, with 9 seeds per plate and 10 replications per treatment, totaling 630 seeds arranged in 7 Petri dishes. The evaluation was performed 8 days later, with the aid of stereoscopic and light microscopy, where the fungal growth in each seed in the plates was verified for the incidence calculation and then the identification of these. Pyroligneous extract was found to be efficient in reducing the fungal incidence of the genera Fusarium sp. and Rhizoctonia sp., fungi considered important plant pathogens that could compromise seed quality and seedling establishment in the field. It also reduced the incidence of storage fungi capable of causing seed deterioration and consequent loss of vigor, such as Aspergillus spp. occurring in seed samples of S. amazonicum. However, Penicillium sp was not controlled by treatment of S. amazonicum seeds with pyroligneous extract up to 12.5% concentration.