Different Aspergillus niger Strains and Inoculum Levels Affect the Nutritional Composition of Olive Leaves in Solid-state Fermentation

This study was conducted to investigate the effects of Aspergillus niger strain and inoculum level on the nutritional composition of olive leaves. The experiment had a 2×3 factorial arrangement of treatments with two A. niger strains (ATCC 200345 [A] and ATCC 9142 [B]) and three inoculum levels (104, 106, and 108). Olive leaves were milled to 2 mm and fermented in solid-state by two different A. niger strains and analysed for nutritional composition. Crude protein (CP) was increased linearly as the inoculum level increased. Ether extract (EE) and crude fiber (CF) were decreased linearly in A strain or quadratically in B strain with increased inoculum levels. Crude ash and nitrogen-free extract content did not differ among groups. Strain A increased neutral detergent fiber (NDF) at higher inoculum level, whereas NDF was decreased as inoculum level increased in B strain. The lowest acid detergent fiber (ADF) was obtained from the B strain or 106 inoculum level. The results showed that the effect of two strains on CP and ADF changed similarly with increased inoculum levels. However, two strains affected EE, CF, and NDF content differently with increased inoculum levels. The optimal situations were 108 inoculum level for higher CP, A104 or B104 for higher EE, B106 for lower CF, B106 or B108 for lower NDF, 106 inoculum level or B strain for lower ADF. B strain at 106 inoculation level can be preferred to obtain an average CP and EE content and lower CF, NDF, and ADF content.

Efficiency of detecting resting spores of Synchytrium endobioticum (potato wart disease) in infested sites of Ukraine and Georgia

Aim. To determine the occurrence and persistence of Synchytrium endobioticum, resting spore contamination in a small survey of (known infested) potato plots in Ukraine and Georgia; to compare the detection efficiency for resting spores (winter sporangia) of S. endobioticum using an extraction method, routinely applied in Ukraine, based on the use of sodium iodide (NaI) and an extraction method largely based on EPPO Standard PM 7/28(2) (2017), using kaolin and calcium chloride (CaCl2) for extraction. Methods. The examination of fields, aimed at detecting of S. endobioticum in 22 infested plots in Georgia, was conducted following the standard European Plant Protection Organisation (EPPO) phytosanitary procedure PM 3/59(3) (2017), and in Ukraine in 11 plots according to the Ukrainian Standard ‘Methodological recommendations on sampling during quarantine inspection and evaluation’ (Omeluta V P et al, 1996). Resting spores were extracted using kaolin and CaCl2 (following largely EPPO Standard PM 7/28(2) 2017), and floatation in a solution of NaI (Zelya et al, 2005), respectively. The content of soil organic matter (SOM), collected in potato wart infested plots in Ukraine and Georgia, was determined according to the ‘Method of laboratory determination of the content of organic matter’, largely following the method of Tyurin to determine total soil organic carbon (Jankauskas B et al, 2006). The persistence or decline of potato wart in infested plots was evaluated, based on our own observations and the data of the national phytosanitary services (https://dpss.gov.ua; http://agr.georgia.gov). The results of the study were subjected to statistical analysis, using Statistica 5 software. Results. It was found that under a low up to high level of organic matter in soil samples (2.0–2.7 and 3.1–3.9 %, respectively) and a moderate to high level of inoculum in soil (3–15 up to 41–65 resting spores/g soil, respectively) there were no significant differences in the efficiency of two extraction methods under consideration: the floatation in a solution of NaI and the application of kaolin and CaCl2. However, at a low number of resting spores present in soil (1–2 resting spores/g soil), the efficiency of the method using NaI decreased statistically significant by 20–30 % as opposed to the method using kaolin/CaCl2. A relatively high level of soil contamination with resting spores was found in 11 investigated plots of 4 Ukrainian regions: 41–46 resting spores/g soil in the Ivano-Frankivsk Region, 49 in the Lviv Region, 40–65 in the Zakarpattia and 52–65 Chernivtsi Regions. The majority of the 22 investigated Georgian plots showed a low inoculum level (1–7 resting spores/g soil) and only in one village their level amounted to 15 resting spores/g soil (Uchguli village, Mestia municipality). Conclusions. The method applying sodium iodide was found to be comparable to the method applying kaolin and CaCl2 under conditions of moderate to high inoculum levels (15–65 resting spores/g soil) but the latter method was more efficient under conditions of high content of organic matter and very low inoculum level (

Inoculum Level and Inoculation Method Influences on the Pathogenic Activities of Meloidogyne incognita in Studied Model Plant Okra (Abelmoschus esculentus L. Moench)

Agricultural activities such as watering crops with nematode-infested water from wells and boreholes, and using infected plant debris as manure or mulch increase root-knot nematode infection. So, this study aims at assessing the influence of the inoculation method and inoculum level of Meloidogyne incognita on the development of root galls on okra plants. Two M. incognita inoculation methods (suspension of individuals and galled root explants) and six inoculum levels (0, 10, 100, 500, 1000 and 2000 second-stage larvae/plant) were studied. The gall index, total numbers and reproductive factor of M. incognita were used to assess the effect of treatments on root gall development. Unlike the reproductive factor, gall index and the total numbers of M. incognita increased with their inoculum level. The pathogenic activities of M. incognita were most significant when crop soils were infested with galled root explants. However, an inverse relationship was found between the inoculum levels of M. incognita and the okra plant’s development. It is reflected by negative correlation coefficients ranging from -0.90 to -0.62. It is therefore important to burn roots infected with root-knot nematodes left in fields so that they do not act as an inoculum for crops.

Effects of Incubation Time and Inoculation Level on the Stabilities of Bacteriostatic and Bactericidal Antibiotics against Salmonella Typhimurium

This study was designed to evaluate the stability of chloramphenicol, erythromycin, tetracycline, cephalothin, ciprofloxacin, and tobramycin against antibiotic-sensitive Salmonella Typhimurium (ASST) and antibiotic-resistant S. Typhimurium (ARST) during the broth microdilution assay. The antimicrobial activity in association with antibiotic stability was measured by using antibiotic susceptibility, time-delayed inoculation, time-extended incubation, and inoculum effect assays. The loss of the antimicrobial activity of cephalothin against ASST exposed to 1 MIC was observed for the 10 h delayed inoculation. The antimicrobial activities of tetracycline and ciprofloxacin against ASST and ARST exposed to ½ MIC were significantly decreased after the 10 h delayed inoculation. All antibiotics used in this study, except for ciprofloxacin, showed the considerable losses of antimicrobial activities against ASST and ARST after 40 h of incubation at 37 °C when compared to the 20 h of incubation during AST. Compared to the standard inoculum level (6 log CFU/mL), the MIC0.1 values of bactericidal antibiotics, ciprofloxacin and tobramycin against ASST were increased by more than 4-fold at the high inoculum level of 9 log CFU/mL. This would provide practical information for better understanding the clinical efficacy of the currently used antibiotics by considering the antibiotic stability during incubation time at different inoculum levels.

​A Non-chemical Approach to the Management of Root Rot Disease Complex of Tomato Concomitantly Caused by Rhizoctonia solani and Meloidogyne javanica

Background: Tomato (Solanum lycopersicum L.) is an important vegetable crop not only for its economic importance but also for its nutritional value. It remained prone to various diseases and amongst them, root rot disease complex caused by concomitant occurrence of R. solani and M. javanica has been key problem in Haryana resultantly reduces yield and production to great extent. Methods: Present study was carried out with the aim to evaluate the effect of organic amendments and biocontrol agents on root rot disease complex in tomato cv. Hisar Arun (Selection 7). Tomato seeds were sown @ 10 seeds/pot filled with sterilized sandy loam soil having 1000 mg/kg soil (Rhizoctonia solani inoculum level) and 1000 J2/kg soil (M. javanica inoculum level). Result: The minimum mortality of 33.3 and 36.6 per cent was observed when the soils were incorporated with mustard cake @ 2g/kg soil followed by cotton cake @ 2g/kg soil in comparison to total mortality of 63.3 per cent in control pots and the soil application of mustard cake protected 47.4 per cent plants from mortality. The application of Glomus mosseae (VAM) at 200, 150, 100 sporocarps/kg soil managed disease to the extent of 36.8% 21.0% and 10.4% respectively. Incorporation of T. harzianum@ 5g/kg soil and 10g/kg soil managed the disease to the extent of 21% and 42% respectively. The minimum mortality of 33.3% was recorded when seeds were dressed with Carbendazim 50WP whereas 36.6 per cent with Carboxin 37.5WP + Thiram 37.5WP in comparison to 63.3 per cent in control pots. Systemic approach to manage the root-rot disease complex with the help of organic amendments, bioagents and fungicides can prevent the losses caused to the crop.

Production of L-glutaminase From Agro-industrial Waste by Halomonas Elongata MM-5 Under Solid State Fermentation

In this study L-glutaminase production by extremely halotolerant Halomonas elongata MM-5 using solid-state fermentation was investigated. Screening of a variety of agro-industrial byproducts such as rice husk, green gram husk, bengal gram husk, red gram husk, safflower oil cake, groundnut oil cake, black gram husk, groundnut skin and wheat bran was carried out individually and in different combinations. Optimization of various physicochemical parameters namely incubation time, pH, temperature, initial moisture content, carbon sources, nitrogen sources, L-glutamine concentration and inoculum level was carried out. Among the various substrates screened individually red gram husk supported the maximum production of enzyme 79.03±0.49 IU/gds. In the mixture of substrates screened red gram husk and bengal gram husk in the ratio (60:40) showed maximum 92.06±1.42 IU/gds enzyme production. The L-glutaminase production was maximum after 4 days of incubation period, pH 8, temperature 40°C and 80 percent moisture content. The lactose and malt extract used as carbon and nitrogen sources respectively supported the maximum yield of L-glutaminase. After screening and optimization of various parameters, the yield of L-glutaminase increased from 79.03 to 159.12 IU/gds.

A field evaluation of jalapeño and non-jalapeño chile pepper resistance to Phytophthora blight caused by Phytophthora capsici

Phytophthora capsici is a destructive soilborne pathogen, which causes Phytophthora blight in many vegetable crops including chile pepper (Capsicum sp.). Our research was aimed at evaluating the resistance of jalapeño cultivars in field conditions and identifying the factors associated with reduction of Phytophthora blight caused by P. capsici. Six jalapeño (NuMex Orange Spice, NuMex Pumpkin Spice, NuMex Jalmundo, TAM Jalapeño, Early Jalapeño, and NuMex Vaquero) and two non-jalapeño (CM-334 and NM 6-4) cultivars were inoculated with P. capsici at the fruiting stage. Disease severity index (DSI), disease incidence (DI), and area under the disease progress curve (AUDPC) for each cultivar were measured. The most susceptible jalapeño cultivars with the highest DSI, DI, and AUDPC were NuMex Orange Spice, NuMex Jalmundo and NuMex Pumpkin Spice, whereas the least susceptible jalapeño cultivars were Early Jalapeño, TAM Jalapeño, and NuMex Vaquero, with the lowest DSI, DI, and AUDPC. The identified jalapeños with reduced susceptibility to Phytophthora blight can be planted in infested fields, combined with other control methods which may help in soil disinfestation by reducing the inoculum level in soil over time.

Effects of moisture and temperature on Salmonella survivability in beef tallow, white grease and chicken rendered fat

High moisture levels introduced to fats after the rendering process can lead to Salmonella presence and growth. Limited research on strategies to eliminate pathogens in these environments are available. Rendered fat characteristics, such as water activity and fatty acids composition, may contribute to Salmonella survivability. The purpose of this research was to evaluate the effects of moisture levels (0%, 0.5%, 1%, and 3%), storage temperatures (48˚C and 76˚C), and fat characteristics on the growth and survival of Salmonella in beef tallow, white grease and poultry fat samples. Samples were inoculated with a high (~10⁸ CFU/mL) and a low (~10⁵ CFU/mL) Salmonella cocktail (S. Sentfenberg, S. Newport, S. Thompson and S. Infantis). Samples were stored for up to 5 days at 48 and 76 ºC. Remaining population was evaluated daily with and without enrichment step. Death rates were calculated using Weibull model for each temperature and moisture level. Only temperature had an effect (P < 0.05) on Salmonella inactivation, while no effect between moisture and/or inoculum level were observed. When all products were challenged at 76 ˚C, counts were below detectable limits after 6 hours. At 48˚C a progressive decline in Salmonella population was observed within 3 days for both beef tallow and white grease when high inoculum was used for the challenge study. Salmonella was below detectable limit within 4 days for both fat types when a low inoculum was instead applied. This research identified the effect of moisture and temperature in rendered fat samples contaminated with Salmonella and underlined the need to use time-moisture-temperature data to minimize microbial growth during transportation and storage.

Optimizing inoculum production methods for infesting soil with Phytophthora species

Inoculum production is an important part of conducting research with soilborne Phytophthora species. One common method is to incubate Phytophthora cultures in nutrient-amended vermiculite. However, inoculum levels often vary among batches of inoculum even when production methods remain the same, and incubation typically takes ≥ 6 weeks, increasing risks for delayed experiments if the resulting inoculum level is too low. A more reliable and rapid method is needed for future studies. Experiments were conducted to: (1) determine inoculum levels of P. cinnamomi and P. plurivora after incubation in V8 juice-amended vermiculite (standard method); (2) evaluate how inoculum viability was affected by air drying; (3) develop a modified method that takes less time to produce a vermiculite-based inoculum; and (4) evaluate the effect of storage on inoculum viability. Results showed that the standard method produced inoculum levels from 716 to 1808 colony forming units/g and that drying to < 78% moisture content significantly reduced viability. The modified method used 2-week-old Phytophthora cultures to infest vermiculite at 80% moisture content and produced inoculum levels from 214 to 525 CFU/g. Storage for >1 day generally reduced inoculum viability. Although inoculum levels from the modified method were lower than the standard method, inoculum levels for each isolate were more consistent between trials and the modified method was 6 to 8 weeks faster. Production with the modified method can also be easily scaled up by infesting a greater volume of vermiculite with additional cultures of Phytophthora. These results are important because they help explain variability in soilborne Phytophthora inoculum production and storage, and provide a new method for producing inoculum more quickly.