Nematode Composition Research Articles

THE USE OF LARVAE BLACK SOLDIER FLY, HERMETIA ILLUCENS, FOR THE DISPOSAL OF POTATOES INFECTED WITH PLANT NEMATODES

Disposal of organic waste in many countries is an acute problem; on the other hand, waste should be considered as an excellent raw material resource. Insect larvae can serve as one of the tools for the processing of organic matter. With their use, you can simultaneously solve several problems: reducing waste, obtaining animal feed, biologically active substances, valuable fertilizer, etc. The paper proposes the use of Hermetia illucens larvae, for the disposal of potatoes infected with plant nematodes. In this work, we evaluated the bioconversion of potatoes by the larvae of the fly H. illucens, and also analyzed the nematode composition of the obtained substrate from potatoes infected with Ditylenchus destructor and Rhabditis spp. during the life of the larvae. H. illucens larvae are able to effectively use fruit and vegetable wastes of com-mercial networks as feed substrate, including those infected with phytopathogenic or saprobiotic nematodes. Analysis of the degree of conversion of the substrate by the larvae of Black soldier fly showed that 70% of the waste was bioconverted. The formed zoo compost did not contain nematodes, in case of infection of the potato used for the experiment with phytoparasitic and saprobiotic nematodes. The ability of H. illucens larvae to eliminate potato and saprobiotic nematodes in the affected root crop has been shown, which makes it possible to recommend this method for utilization of potatoes spoiled during storage.

New Insights Into Nematode DNA-metabarcoding as Revealed by the Characterization of Artificial and Spiked Nematode Communities

Nematodes are ideal biological indicators to monitor soil biodiversity and ecosystem functioning. For this reason, they have been receiving increasing attention from a broad range of scientists. The main method to characterize soil nematode communities until at least genus level is still based on microscopic observations of nematode morphology. Such an approach is time-consuming, labor-intensive, and requires specialized personnel. The first studies on the potential use of DNA-metabarcoding to characterize nematode communities showed some shortcomings: under- or overestimation of species richness caused by failure to detect a number of nematode species or caused by intraspecific sequence variants increasing the number of OTUs (operational taxonomic units) or ‘molecular’ species, and flaws in quantification. We set up experiments to optimize this metabarcoding approach. Our results provided new insights such as the drastic effect of different DNA-extraction methods on nematode species richness due to variation in lysis efficacy. Our newly designed primer set (18S rRNA gene, V4-V5 region) showed in silico an improved taxonomic coverage compared with a published primer set (18S rRNA gene, V6-V8 region). However, results of DNA-metabarcoding with the new primer set showed less taxonomic coverage, and more non-nematode reads. Thus, the new primer set might be more suitable for whole soil faunal analysis. Species-specific correction factors calculated from a mock community with equal amounts of different nematode species were applied on another mock community with different amounts of the same nematode species and on a biological sample spiked with four selected nematode species. Results showed an improved molecular quantification. In conclusion, DNA-metabarcoding of soil nematode communities is useful for monitoring shifts in nematode composition but the technique still needs further optimization to enhance its precision.

Response of Soil Nematode Community to Phosphorous Amendment in a Subalpine Spruce Plantation

An appropriate management practice is indispensable to the restoration of ecological functioning, particularly in ecologically vulnerable regions. The short‐term effects of phosphorous (P) amendment on community structure and function of soil micro‐food webs in a subalpine spruce (Picea asperata) plantation are examined. Experimental plots are established and treatments are performed with P addition at two levels: Low P (LP) input of 5 g m−2 per year and high P (HP) input 30 g m−2 per year as NaH2PO4 · 2 H2O, and in control plots (CK) without external P input. The abundance, diversity, functional indices, community composition, and metabolic footprints of soil nematodes in the experimental plots are monitored for two consecutive growing seasons during 2013–2014 following P addition. A high variation of abundance of nematodes is observed especially in HP treatment, with reduction in abundance of omnivores and predators. Similarly, maturity index of free‐living nematodes, plant parasitic index, enrichment index, structure index, and predator footprint are significantly reduced. However, basal index and channel index of soil nematodes are apparently increased in both years. Moreover, P addition considerably shifts soil nematode community composition, which correlates to soil pH, total P content, available P content, and molar C/P and N/P in soils. In summary, the results indicate that the impacts of P addition on soil nematode community in spruce plantation are mediated by changes in soil pH, P status, and C/N/P ecological stoichiometry.

Long-term changes (1979-2015) in the nematode fauna in Sivash Bay (Sea of Azov), Russia, worldwide the largest hypersaline lagoon, during salinity transformations

Summary Sivash Bay is the largest hypersaline lagoon in the world. In 1963-1975 the North Crimean Canal was constructed, with water from the River Dnieper and discharge of drainage water collected from agricultural lands into Sivash Bay. Salinity in Sivash Bay began to drop, resulting in a new brackish water ecosystem. The political decision to stop supplying water from the River Dnieper to the Canal was made in 2014, and the discharge of fresh water into the lagoon ended, resulting in an increase in salinity up to 60-75 g l−1. This study showed that the abundance of meiobenthos increased, with Nematoda dominating. The composition of nematode species in the lagoon has not previously been studied. Using samples from 1979, 2013 and 2015, 50 nematode species and forms were identified in 1979, 32 in 2013 and 21 in 2015. The species composition of nematodes at different periods was significantly different. The average abundance of nematodes was 134 198 ind. m−2 in 2013 and 606 660 ind. m−2 in 2015.

Community Composition of Parasitic Nematodes of Cyprinion Macrostomum from North and Mid West Regions In Iraq

Community Composition of Parasitic Nematodes of Cyprinion Macrostomum from North and Mid West Regions In Iraq

Biodiversity and distribution of meiofauna in the Gioia, Petrace and Dohrn Canyons (Tyrrhenian Sea)

Habitat heterogeneity is a major structuring agent of benthic assemblages promoting high turnover in species composition and ultimately contributing to overall higher diversity. Submarine canyons, a pervasive feature of the continental margins worldwide, increase habitat heterogeneity at multiple spatial scales. In the present study, we test the hypothesis that different topographic structures or/and food sources controlling the abundance, biomass and biodiversity (using meiofauna and nematodes as a model study) in canyon systems. To do so, we compared different topographic structures: canyon edge, thalweg and axis, and the upper shelf and open slope in the Gulf of Gioia (Gioia and Petrace Canyons) and in the Gulf of Naples (Dohrn Canyon) (Tyrrhenian Sea) at different depths. Our results suggest that meiofaunal abundance and biomass are generally higher in the canyon thalwegs than in the canyon edge or adjacent open slopes at regional scale. This pattern is not always confirmed for biodiversity and when thalwegs are compared to different topographic structures within the Gioia Canyon system. In our study, the role of food quantity and quality is preeminent to explain the spatial distribution of meiofaunal variables among different topographic structures at 200-m while habitat heterogeneity become relevant at 500-m and within the Dohrn Canyon. In Gioia and Petrace Canyons we observed a high food availability is associated to specific topographic structures (thalwegs) that influenced the meiofaunal abundance and diversity distribution and nematode diversity and species composition. Each topographic structure shows a high number of exclusive species that contributes to a high species turnover and high overall biodiversity in all canyon systems. Changes in nematode composition determine also differences in the functional diversity (trophic guilds composition) and life strategy of the nematode assemblages. Our findings reveal that the presence of different topographic structures influences the spatial distribution of food quality and quantity that determine the presence of exclusive taxa and species enhancing both local and regional diversity.

Исследования галловых нематод рода Meloidogyne (Goeldi, 1877) на территориях Болгарии и Российской Федерации

The purpose of the research is analysis of data on the species and racial composition of pathogenic nematodes of the genus Meloidogyne in Bulgaria and Russia. Materials and methods . The analysis of own and literary data on the distribution of root-knot nematodes on the territory of two countries was carried out. Results and discussion . Five species of Meloidogyne both under open-field and greenhouse conditions in Bulgaria were established (M. incognita, M. arenaria, M. javanica, M. hapla and M. thamesi). They successfully develop under greenhouse and open-field conditions and invade vegetables and ornamental plants. M. javanica predominantly develops under greenhouse conditions, but in South-Western part of Bulgaria it reproduces itself under open-field conditions and is one of the usual species of plant parasitic nematodes there. M. hapla is widespread both under greenhouse and open-field conditions. First in Bulgaria race 1 of M.arenaria was found. Investigations of M. hapla race composition found statistically reliable differences (length of stylet, length of J2, some differences of knobs morphology). On the territory of Russian Federation five species belonging to Meloidogyne were found (M. incognita, M. arenaria, M. javanica, M. hapla and M. ardenensis). The first three species develop only under greenhouse conditions and damage vegetables and ornamental plants. M. hapla is distributed from the most North-Western regions of Russia to the North Caucasus It successfully develops on the roots of all except cucumbers. At the time being Meloidogyne ardenensis has been found only on the roots of birch tree. M. hapla is distributed on the territories of the two countries with numerous hosts and which is very important – it damages potatoes. The results obtained investigations of M. hapla race composition are important for choice of the best methods for prevention and control.

Differential species characters of Baruscapillaria anseris and B. obsignata nematodes obtained from the domestic goose

The study presents species composition and abundance of nematodes of the family Capillariidae (Nematoda, Trichocephalida), parasitizing the domestic goose (Anser anser dom. Linnaeus, 1758) in Poltava region, Ukraine. Morphological specifics of adult specimens of collected helminths are examined and new data is obtained for species identification of Capillariidae considering their metric parameters. The pathogens of capillariasis in geese are represented by two species, Baruscapillaria anseris (Madsen, 1945) Moravec, 1982 and B. obsignata (Madsen, 1945) Moravec, 1982 with the former predominant. Prevalence of infection by B. anseris in domestic fowl was up to 46.8%, the abundance index reached 17.9 specimens. The proportion of geese infected with B. obsignata was 23.9%, and the abundance index was 3.8 specimens. Morphological study of the collected mature male and female nematodes revealed the significant similarity of both species in the general body structure and in identification characters: vulva and vagina structure in females, tail end, spicule and spicule sheath in males. Statistically significant differences were determined in the metric parameters of male and female B. anseris and B. obsignata nematodes. Those differences can be used to improve species identification. Males of B. anseris were larger than males of B. obsignata by 16 metric parameters including the length and width of body, spicule and spicule sheath, width of pseudobursa, and distance between the rays of pseudobursa. Females of B. anseris and B. obsignata were significantly different by seven metric parameters. By five parameters (length and width of various body regions) the B. anseris females were larger than B. obsignata. Metric parameters of the studied species are also of interest for taxonomic identification: the eggs of B. obsignata are longer and narrower than those of B. anseris.

Structure and function of nematode assemblages in contaminated sediments: what can we learn from the Mar Piccolo of Taranto (Ionian Sea)?

Free-living nematodes were investigated in the Mar Piccolo of Taranto (Ionian Sea), a semi-enclosed basin of strategic importance for its complex productive infrastructure but in need of remediation due to the alarming amounts of heavy metals and synthetic organic contaminants in the sediments. Abundance, genera composition, biodiversity and trophic traits of nematodes were related to the gradual transition from marine to more brackish conditions and to the varying levels of contaminants in different sub-areas of the basin. Nematodes were more abundant and diverse at the most marine site while low numbers and diversity characterized the most contaminated station. Going towards the innermost part of the basin, gradually increasing values of abundance and biodiversity were observed although the assemblage was susceptible to the organic enrichment caused by mussel farms. The use of nematodes as ecological indicators mirrored the response of the assemblage to the main patterns acting in the basin (High/Good scores at the most marine site and Poor/Bad scores at the most contaminated station), giving a clear indication of environmental quality to stakeholders/authority that can contribute to address remediation actions in contaminated sediments.

Nematodes in Meiobenthos and Periphyton of the Rybinsk Reservoir (Review)

This paper presents data on changes in the taxonomic composition and abundance of nematodes in meiobenthos and periphyton of the Rybinsk Reservoir in the long term. The species composition of roundworms in bottom communities is significantly richer and their number is manyfold higher than among fouling organisms. These differences are determined by the different habitat conditions at the bottom and hard substrate surfaces in the water column. In modern anthropogenically disturbed zones of various waterbodies, the biocenotic and functional roles of nematodes depend to a larger extent on food availability than on some other environmental factors limiting the development of worms. Roundworms, living under a wide range of ecological conditions, are one of the key groups of invertebrates critical for preserving aquatic life under anthropogenic stresses.

Comparative morphology and biology of nematodes of genus Heterakis (Nematoda, Heterakidae), parasites of the domestic goose (Anser anser) in Ukraine

The genus Heterakis Dujardin, 1845 is one of the most widely distributed genera of nematode parasites of domestic and wild birds. Geographically and ecologically predominant species include Heterakis gallinarum Schrank, 1788 and Heterakis dispar Schrank, 1790. Prevalence and occurrence of these nematodes in the domestic goose (Anser anser dom.) depend on their biological and morphological specifics which ensure the highest viability, fast growth and maximum fertility in the host. This study presents the abundance and species composition of nematodes of the genus Heterakis in the domestic goose in Ukraine. Comparative study of morphological and metrical characteristics of H. gallinarum and H. dispar adult females and males is presented. Additional morphometric characteristics are proposed for easier identification of the two species. Stages and periods of embryonic development of H. gallinarum and H. dispar nematodes obtained from domestic geese are established according to morphological and metrical characters. Of the two species, H. dispar is prevalent in domestic geese from Poltava, Kharkiv and Kyiv regions. Abundance index of this species is 9.8 specimens, and intensity of infection index is up to 62 specimens. H. gallinarum is rarer, its abundance index is 1.2 specimens and maximum intensity of infection is 30 specimens. Species-specific morphological differences are more distinct in male nematodes in the size and structure of the spicules, lateral wing-like protrusions of pseudobursas, numbers and position of tail papillae. Additional metrical characteristics differ between H. gallinarum and H. dispar nematodes, allowing us to identify not only adult specimens but also eggs. Embryonic development of both species occurs in four morphologically distinct stages: protoplast, blastomere cleavage, formation of first and second stage larvae. Eggs of H. gallinarum nematodes become infectious in eight days at 27 °С, eggs of H. dispar in four days, their viability in laboratory culture is 84.3 ± 0.58 and 91.3 ± 1.53% respectively.

Response of Soil Nematodes Under Different Pest Management Practices: A Field Experimental Approach in Tomato (Lycopersicon Esculentum L.) Growing Agro-Ecosystem

The need of eco-friendly pest management practice is important to maintain soil biodiversity and sustainable agriculture. Therefore rigorous investigation is needed for the environmentally friendly pest management techniques worldwide including Nepalese Tomato growing farms. We conducted field experiment to monitor the diversity and community structure of soil nematodes under different pest management practices in Tomato (Lycopersicon esculentum) growing farm. The study was conducted during summer and winter season in 2015 in Tokha area of Northern part of Kathmandu valley. The field was designed as Urine mixture plot (MP), Pesticides plot (PP), Botanicals plots (BP) and Control plot (CP). Our result indicated the variation of abundance and diversity of nemato-fauna with treatment plots and seasons. The generic diversity and community composition of nematodes in Urine mixture treating plots (MP) was increased significantly whereas decreased in pesticide applying plot (PP). The F/B ratio was significantly affected with treatment system rather than seasonality and found to be increased in pesticides applying plots. The abundance samples of nematodes genera were well separated in our discriminate ordination. We highlight the need of further exploration on the diversity and community dynamics of soil nematodes under different pest management practices in Tomato growing Nepalese agro-farms for sustainable soil ecosystem service. Journal of Institute of Science and Technology Volume 22, Issue 2, January 2018, Page: 45-55

Nematode indicators as integrative measures of soil condition during conversion from conventional to organic rice production in Italy: a case study

The Vercelli district is one of the most technologically advanced rice cultivation areas in the world, but the sector is causing serious environmental problems. This study aimed to acquire information on the ecological impact during conversion from conventional to organic farming, using the nematode community as an indicator of soil quality. An organic farming system managed with a 5-year crop rotation, based on rice (4-years) and soybean (1-year), was compared, during the fourth and fifth year after conversion, with conventional and integrated farming systems, both based on monoculture of rice. The relationship between soil biology and the type of farming system was explored by examining the nematode community, assessing maturity, plant parasitic, basal, enrichment, structure, channel indices and diversity-weighted abundance. No significant differences in total soil organic C, total N and C/N ratio were found between the management systems. Total nematode abundance was not strongly affected by the conversion, but the response of the nematodes to change varied with the trophic groups, year by year. The conversion from conventional to organic farming represented a disturbance factor. The introduction of the soybean crop determined a marked change in nematode composition; the persistent nematode population was only 20%, while the colonizer reached 80%. The indices showed that the nematode community varied between the farming system; in both years maturity index was lower in organic than in other management systems. Higher values of pH, C/N ratio and available P favoured basal and channel indices, while total N was negatively correlated.

Population Fluctuation of Soil Inhabiting Nematodes in Relation to soil Temperature and moisture at Guava orchard in West Bengal, India

Soil edaphic factors like temperature and moisture are important for the community composition of nematodes. Those were considered to assess their effects upon the population of soil nematodes. The present work was carried out in a guava (Psidium guajava L.) orchard at Shalipur (West), Baruipur block of South 24-Parganas for three consecutive years. The results revealed that the maximum populations of nematodes were observed during monsoon with a population of 4169/250gm of soil in the month of July. During monsoon low soil temperature (30.10C - 31.80C) and high soil moisture (20% - 26%) in the month of July were also observed. The minimum population (204/250gm of soil) of soil nematodes was observed during pre- and post-monsoon with a wide range of low to high soil temperature (180C - 340C) and low soil moisture (10% - 13%). This reveals a direct effect of these two climatic factors of soil on the population of soil nematodes which has been established by correlation and regression analysis.

Effect of organic amendment amount on soil nematode community structure and metabolic footprints in soybean phase of a soybean-maize rotation on Mollisols

It has been well documented that organic amendment affects soil nematode community structure. However, little is known about the effect of organic amendment amount on soil nematodes. To assess the effect of the amount of organic amendments on soil nematode community structure and metabolic activity, the community composition, abundance, and metabolic footprints of soil nematodes were determined in a long-term field experiment with various amounts of organic amendment in Northeast China. Fertilization treatments included an unfertilized control (CK), chemical fertilizer without manure amendment (OM0), manure applied at 7.5 Mg ha–1 plus chemical fertilizer (OM1), and manure applied at 22.5 Mg ha–1 plus chemical fertilizer (OM2). A total of 46 nematode genera were found. Treatments with the largest amount of organic amendment had the smallest number of plant parasite genera (5), but a largest number of dominant genera (7). Soil nematodes, bacterivores, and fungivores were the most abundant in OM2, followed by OM1, and the lowest in OM0 and CK. Organic amendment increased the enrichment index (EI), and the large amount of organic amendment increased the metabolic footprints of bacterivore (Baf) and fungivore (Fuf) and enrichment footprint (Ef). The relationships between Baf (or Fuf) and the increases in soil organic carbon (ΔSOC) and total nitrogen (ΔTN) were stronger than those of bacterivore (or fungivore) abundance with ΔSOC and ΔTN, except for the relationship between bacterivore abundance and ΔSOC. The EI and Ef were positively correlated with ΔSOC and ΔTN. These findings suggest that the amount of organic amendment affects soil nematode activity and function at entry levels in soil food web, and that metabolic footprints of soil nematodes may be better indicators than their abundances in assessing their relationships with soil nutrients.

Disentangling the root- and detritus-based food chain in the micro-food web of an arable soil by plant removal.

Soil food web structure and function is primarily determined by the major basal resources, which are living plant tissue, root exudates and dead organic matter. A field experiment was performed to disentangle the interlinkage of the root-and detritus-based soil food chains. An arable site was cropped either with maize, amended with maize shoot litter or remained bare soil, representing food webs depending on roots, aboveground litter and soil organic matter as predominant resource, respectively. The soil micro-food web, i.e. microorganisms and nematodes, was investigated in two successive years along a depth transect. The community composition of nematodes was used as model to determine the changes in the rhizosphere, detritusphere and bulk soil food web. In the first growing season the impact of treatments on the soil micro-food web was minor. In the second year plant-feeding nematodes increased under maize, whereas after harvest the Channel Index assigned promotion of the detritivore food chain, reflecting decomposition of root residues. The amendment with litter did not foster microorganisms, instead biomass of Gram-positive and Gram-negative bacteria as well as that of fungi declined in the rooted zone. Likely higher grazing pressure by nematodes reduced microbial standing crop as bacterial and fungal feeders increased. However, populations at higher trophic levels were not promoted, indicating limited flux of litter resources along the food chain. After two years of bare soil microbial biomass and nematode density remained stable, pointing to soil organic matter-based resources that allow bridging periods with deprivation. Nematode communities were dominated by opportunistic taxa that are competitive at moderate resource supply. In sum, removal of plants from the system had less severe effects than expected, suggesting considerable food web resilience to the disruption of both the root and detrital carbon channel, pointing to a legacy of organic matter resources in arable soils.

Spatial and temporal variation of intertidal nematodes in the northern Gulf of Mexico after the Deepwater Horizon oil spill

Nematodes are an abundant and diverse interstitial component of sedimentary habitats that have been reported to serve as important bioindicators. Though the 2010 Deepwater Horizon (DWH) disaster occurred 60 km offshore in the Gulf of Mexico (GOM) at a depth of 1525 m, oil rose to the surface and washed ashore, subjecting large segments of coastline in the northern GOM to contamination. Previous metabarcoding work shows intertidal nematode communities were negatively affected by the oil spill. Here we examine the subsequent recovery of nematode community structure at five sites along the Alabama coast over a two-year period. The latter part of the study (July 2011–July 2012) also included an examination of nematode vertical distribution in intertidal sediments. Results showed nematode composition within this region was more influenced by sample locality than time and depth. The five sampling sites were characterized by distinct nematode assemblages that varied by sampling dates. Nematode diversity decreased four months after the oil spill but increased after one year, returning to previous levels at all sites except Bayfront Park (BP). There was no significant difference among nematode assemblages in reference to vertical distribution. Although the composition of nematode assemblages changed, the feeding guilds they represented were not significantly different even though some variation was noted. Data from morphological observations integrated with metabarcoding data indicated similar spatial variation in nematode distribution patterns, indicating the potential of using these faster approaches to examine overall disturbance impact trends within communities. Heterogeneity of microhabitats in the intertidal zone indicates that future sampling and fine-scale studies of nematodes are needed to examine such anthropogenic effects.

Interannual patterns of the large free-living nematode assemblages in the Mexican Exclusive Economic Zone, NW Gulf of Mexico after the Deepwater Horizon oil spill

The presence and abundance of particular nematode genera in marine sediments are bioindicators of environmental disturbance. They can even reveal the existence of specific toxicants, such as trace-metals and hydrocarbons derived from fossil fuels. We studied this important infaunal component during a three-year monitoring program in Mexico’s Exclusive Economic Zone (EEZ) in the aftermath of a major oil spill in the northern Gulf of Mexico caused by the sinking of the Deepwater Horizon platform (DWH) in April of 2010. A closer look at the nematode composition and density values throughout and after the DWH oil spill revealed considerable changes. Continental shelf and upper slope sediments sampled in the summer of 2010 included 48 genera and a density of 44.45 ind/10cm−2. Eight months later in the winter of 2011, there was a critical decrement in genera number (23) and density (25.22 ind/10cm−2). However, in 2012, the nematode community showed signs of recovery: genus diversity was 58 with a density of 91.45 ind/10cm−2. Significant differences were recorded between the first and the last sampling periods, driven by a remarkable turn-over in genera composition, and by an increase in density of the genera Sabatieria, Dorylaimopsis, and Cheironchus. Similarly, significant spatial differences between the nematofauna of the inner-middle shelf and the deepest zone (>2000m) were detected. Correlation analyses confirmed the tolerant behavior of the above genera to Ni and Co, and their proliferation when hydrocarbon compounds presumably derived from the DWH oil spill increased throughout the study. The Maturity Index (MI) estimated for each survey ranged from 2.35 to 2.6. Environmental Quality Status conditions in the summer of 2010 were good while in the winter of 2011 were poor, and moderate towards the winter of 2012. Index of Trophic Diversity (ITD) values for each survey were high: 0.70, 0.68, and 0.74, respectively. A high predominance of feeding guilds 1B and 2B was recorded throughout the study.The estimated Index of Trophic Diversity (ITD) values resulted high (Table 5). These values apparently indicated that the four feeding types were proportionally distributed in the nematode assemblage. This fact was better reflected during the winter of 2012. Nonetheless, these results are not congruent with the high predominance of feeding guilds 1B and 2B observed throughout the study.

Gut Helminth Composition in Newly Comigrating Light Geese (Lesser Snow GooseChen caerulescens caerulescensand Ross’ GooseChen rossii)

Light geese (Chen caerulescens caerulescens and Chen rossii) have recently come into contact along a shared migration route. Parasite burdens were compared by examining the digestive tracts of 48 newly comigrating light geese (38 lesser snow geese and 10 Ross’ geese) collected from 4 February to 3 March, 2012 during spring migration through central Illinois. Eight helminth taxa, including four species of Nematoda (Amidostomum sp., Epomidiostomum sp., Heterakis dispar, Trichostrongylus tenuis), two species of Trematoda (Echinostoma revolutum, Zygocotyle lunata), and two species of Cestoda (Cestoda sp. A, Cestoda sp. B), were recovered. Five of the eight helminth taxa were common in both species of host while Cestoda sp. B, Z. lunata, and E. revolutum were only found in lesser snow geese. Nematodes dominated assemblages, and all had a direct life cycle. Prevalences ranged from 22% (Amidostomum sp., C. rossii) to 100% (Epomidiostomum sp., C. c. caerulescens, T. tenuis, and C. rossii). Trematodes, which use an indirect life cycle, were relatively rare with a prevalence less than 10%. Host species and age showed significant effects on nematode composition whereas host sex had no effect. The prevalence of H. dispar was higher in adults than in juveniles for both species. Prevalence and mean intensity of T. tenuis was higher in Ross’ geese than in lesser snow geese, and mean intensity was higher in juvenile than in adult Ross’ geese. Patterns generally followed historic records, but infection levels were lower than previous reports from wintering and breeding ground surveys. While comigrating Ross’ geese and lesser snow geese share similar parasite assemblages overall, multivariate analysis showed clear discrimination between species and with age, indicating that the recent shift in migration patterns has not resulted in a homogenization of their parasite communities.

Концептуальные основы интегрированной защиты основных сельскохозяйственных культур от цистообразующих нематод

Objective of research. To elaborate a framework for integrated protection of agricultural crops from oat, sugar beet, Golden potato, alfalfa and clover nematodes.
 Materials and methods. The effectiveness of different anti-nematode measures was studied in 1991-2016 in Vinnyza, Kiev, Sumy, Chernigov and other regions of Ukraine. As research material served samples of soil, plants; eggs, larvae, imago; beet, oat, Golden potato, alfalfa and clover cyst nematodes. Preparation of temporary and permanent slides, determination of the species composition of cyst nematodes were carried out by standard methods [3, 6].
 Results and discussion. The framework of integrated protection of agricultural crops from oat, sugar beet, Golden potato, alfalfa and clover nematodes has been elaborated. To prevent mass reproduction of cyst-forming nematodes, the saturation of crop rotations with host plants must not exceed 40% — with cereal grains; 20% — beet and oilseed Brassica (canola, radish, and mustard); 15% — potatoes; 20% — perennial legumes. Involvement of crops and green manure in the by-products cycle has a positive effect on the level of soil fertility and activation of life activity of natural antagonists of Heteroderidae