Verkapselung von bakteriellen Antagonisten und eines nematophagen Pilzes

Data and results are presented from a project on the development and application of hydrogel capsules for the delivery of two biological control agents, namely bacterial antagonists to control phytopathogenic fungi and a nematophagous fungus to control plant-parasitic nematodes. The focus is on encapsulation on lab and technical scales, drying and storage of the formulations, application to the greenhouse and field, and technology transfer to a biocontrol company.     

The Seasonal Variation in Bioactive Compounds Content in Juice from Organic and Non-organic Tomatoes

A specific objective of this paper was to evaluate seasonal changes in bioactive compounds level (carotenoids and polyphenols) in juice prepared from organic and non-organic tomatoes in Poland. In the examined tomato juice, the content of dry matter, vitamin C, carotenoids as well as polyphenols (by HPLC method) has been measured. The presented results indicate the impact of the growing system and the year of production on the composition of tomato juice. The organic tomato juice contained significantly more beta-carotene, chlorogenic acid, rutin as well as more total phenolic acids, gallic acid, p-coumaric acid, total flavonoids, quercetin-3-O-glucoside and quercetin in comparison with the non-organic. The tomato juice from 2008 contained significantly more carotenoids and some flavonoids compared to the one produced in 2009, which contained significantly more dry matter, vitamin C, as well as quercetin and it derivatives.     

Nematicidal potential of aqueous and ethanol extracts gained from Datura stramonium,D. innoxia and D. tatula on Meloidogyne incognita

Journal of Plant Diseases and Protection - The nematicidal effect of aqueous and ethanol extracts from leaves, roots and mixed plant parts...     

Damage thresholds and population dynamics of <Emphasis Type="Italic">Pratylenchus penetrans</Emphasis> on carrot (<Emphasis Type="Italic">Daucus carota</Emphasis> L. cv. Nerac) at three different seed densities

Yield and quality loss of carrot (Daucus carota L. cv. Nerac) caused by Pratylenchus penetrans and the population dynamics of this nematode were studied in a climate controlled glasshouse. A range of 12 nematode densities was used at three different seed densities of carrot; 2, 4 and 18 seeds pot^?1. Seinhorst’s yield loss model; y?=?m?+?(1 - m) 0.95 ^Pi/T-1 for Pi?>?T; y?=?1 for Pi?≤?T for Tylenchina was fitted to the yield and quality loss data. Seinhorst’s model for population dynamics of migratory nematodes with multiple generations; \( Pf=M* Pi/\left( Pi+M/a\right) \) was fitted to the data of the final population densities (Pf). P. penetrans had a significant impact on carrot taproot yield and its quality. The tolerance limits for the relative carrot taproot yield (T _y) were 1.51, 1.88, and 1.37 and those of quality yields (T _q) were 0.67, 0.18, and 0.40 P. penetrans (g dry soil)^?1 at 2, 4 and 18 seeds pot^?1, respectively. Both the minimum yield (0.20, 0.29, and 0.60) and the minimum quality yield (0.05, 0.07, and 0.20), expressed as a proportion, increased with seed density at 2, 4 and 18 seeds pot^?1, respectively. The model for population dynamics fitted well to the Pf data obtained. The maximum multiplication rates (a) were 19.58, 9.99, and 17.54, while the maximum population densities (M) were 49.86, 43.21, and 60.37 P. penetrans (g dry soil)^?1 at 2, 4, and 18 seeds pot^?1, respectively. Carrot cv. Nerac can be considered a good host for P. penetrans.     

Air sacculitis in poultry--human relevance of E. coli-isolates from the body cavity of turkeys unfit for human consumption

Air sacculitis is a common lesion found in herds during poultry meat inspection. To support the decision during inspection, 101 carcasses from turkey herds with frequently occurring air sacculitis (unfit for human consumption because of air sacculitis) were examined and 96 E. coil-isolates were collected. The isolates were tested for EHEC/STEC, i.e. gene sequences encoding Shigatoxin 1 and 2, EHEC-hemolysin (hlyEHEC) and intimin (eae). Moreover, the minimal inhibitory concentration (MIC) of the isolates to 13 antimicrobial substances was tested. Factors determining EHEC or STEC were not identified. MIC to several substances were higher, related to the reference strain. Regarding the farm units, some of the respective strains had more frequently higher MIC. Based on these results, in case of air sacculitis, the decision should depend on macroscopic lesions exclusively.     

Report on the 42nd joint meeting of the DPG-working group Nematology and the working group “free living nematodes”

Journal of Plant Diseases and Protection -     

Virulence of Meloidogyne incognita populations and Meloidogyne enterolobii on resistant cucurbitaceous and solanaceous plant genotypes

Journal of Plant Diseases and Protection - Root-knot nematodes (Meloidogyne spp.) cause extensive damage to tomato and cucurbit crops in protected cultivation systems. An environmentally benign...     

Toxicity of fungal endophyte secondary metabolites to plant parasitic nematodes and soil-borne plant pathogenic fungi

Fungi isolated from the cortical tissue of surface sterilized tomato roots collected from field plots produced secondary metabolites in nutrition broth that were highly toxic toMeloidogyne incognita. Especially strains ofFusarium oxysporum were highly active with 13 of 15 strains producing culture filtrates toxic to nematodes. The mechanism of action of the toxic metabolites produced by the non-pathogenicF. oxysporum strain 162 with proven biological control ofM. incognita in pot experiments was investigated. These metabolites reducedM. incognita mobility within 10 min of exposure. After 60 min, 98% of juveniles were inactivated. Juveniles were initially inactivated within a few minutes of exposure, but with exposure of 5 h 50% of the juveniles were dead and 24 h exposure resulted in 100% mortality. In a bioassay with lettuce seedlings metabolite concentrations > 100 mg/l reduced the number ofM. incognita juveniles on the roots comparing to the water control. TheF. oxysporum toxins were highly effective towards sedentary parasites and less effective towards migratory endoparasites. Nonparasitic nematodes were not influenced at all. Metabolites of strain 162 also reduced significantly the growth ofPhytophthora cactorum, Pythium ultimum andRhizoctonia solani in vitro. Secondary metabolites of endophytic fungi on plant-parasitic nematodes and soil-borne fungi should be considered for control of plant parasitic nematodes and plant pathogenic fungi. The results also show the need for proper selection of target nematodes inin vitro bioassays.