Aphelenchoides Composticola Research Articles

TROPHIC DIVERSITY OF LITTER NEMATODE COMMUNITIES OF FORESTS IN THE MEZIN NATIONAL NATURE PARK

Introduction. Nematodes are one of the most abundant groups of the soil and litter fauna in forest ecosystems. The faunal composition may mirror the activity of decomposition pathways and give indications of nutrient status and fertility of soil. Nematodes play an important role in regulating microbial communities and affect the speed and direction of mineralization and humification of plant precipitation.
 Aim. Trophic structure of nematode communities from litter in forests of the Mezin National Nature Park was studied.
 Materials and methods. Samples litter were collected from June to July 2010 and 2014 in 21 forest ecosystems. Nematodes were extracted by a modified Baermann’s method from the 5-g sample. The exposition time was 48 h. Extracted nematodes were fixed in the triethanolamine–formalin (TAF, 2 % triethanolamine, 7 % formaldehyde solution, 91% water), and mounted on the temporary hydroglyceric slides. Nematode abundance was expressed as specimens per 100 g of dry substrate.
 Results. The 46 identified nematode species were divided into five trophic groups: saprobionts, mycohelminths, omnivores, predators and phytohelminths. Saprobionts were both the most diverse and the most numerous. 26 species (56,52% of all species collected) belonged to the this trophic group, proportion in the community was 63,97%. Plectus cirratus, Plectus parietinus, Panagrolaimus rigidus were the most numerous (proportion in the community 24,13%, 9,65% and 8,18% of the total, respectively). P. rigidus occurred in 95,2% of all samples. Aphelenchoides composticola dominated among 10 species of mycohelminths (frequency was 85,7%, proportion in the community 8,99%). Mesodorylaimus bastiani was common аmong the three species of omnivorous nematodes (frequency was 90,48%, proportion in the community 13,74%). Predatory nematodes (5 species) were in 57,1% of samples, proportion in the community together was 3,17%. Only two species phytohelminths (Gracilacus audriellus, Paratylenchus nanus) were found in the analyzed litter samples. They were rare; their frequency was 9,52% and 4,76% respectively. Moreover they were not very abundant (0,12% and 0,08% of total number respectively).
 Conclusions. The mycohelminths and saprobionts make an important component of the litter decomposer community of all forest ecosystems in the Mezin National Nature Park. The ratio of mycohelminths to saprobionts (М/S) shows a constant preponderance of saprobionts and was 0,27. Twenty five species (54,35% of all species collected) were high colonization ability, high reproduction rate and high tolerance to disturbances. The trophic diversity index was 2,16. The maturity index was 2,27. These indexes show stability of habitat in the forest litter.

Taxonomic Structure of Nematode Communities of Epiphytic Mosses in Green Plantations of Chernihiv, Ukraine

Abstract In the city of Chernihiv, nematodes of epiphytic mosses were studied for the fi rst time. 40 nematode species belonging to 30 genera, 20 families and 8 orders were revealed. Most of the identifi ed species belonged to the order Rhabditida: 12 species or 30 % of total number. Nematodes of the order Plectida were the most abundant in the studied communities, they composed 61.21 % of total specimens collected. Nine species: Plectus parietinus (Bastian, 1865) Paramonov, 1964, Mesodorylaimus bastiani (Butschli, 1873), Geomonhystera villosa Butschli, 1837, Tylocephalus auriculatus (Butschli, 1873) Anderson, 1966, Aphelenchoides composticola Franklin, 1957, Panagrolaimus rigidus (Schneider, 1866) Thorne, 1937, Eudorylaimus circulifera Loof 1961, Plectus parvus (Bastian, 1865) Paramonov, 1964, Laimaphelenchus penardi (Steiner, 1914) Filipjev et Sch. Stek., 1941 constituted the core of nematode communities in epiphytic mosses.

Effect of transgenic insect-resistant maize to the community structure of soil nematodes in two field trials

Summary The aim of this study was to determine the effects of Bt maize hybrid cultivation on soil nematode communities in two field trials, as well as to analyse other factors (fertilisation and moisture) responsible for the community structure of soil nematodes. Nematode communities were studied in maize plots at the locality of Borovce in western Slovakia. During 2012 and 2013, hybrids DK440 and DKC3871 (conventional) or DKC4442YG and DKC3872YG (Bt maize, event MON810) were sown in 10 repetitions each. Nematodes were extracted from soil samples collected at the maize flowering (July 11, 2012 and July 30, 2013). Altogether, 39 nematode species belonged to 35 genera were identified in two maize variants. The dominant taxa in both variants were Acrobeloides nanus, Ce-phalobus persegnis, Aphelenchoides composticola, Aphelenchus avenae, Eudorylaimus carteri and Filenchus vulgaris. Calculation of the maturity index, plant parasitic index, enrichment index and structure index did not confirm any clear influence of year or hybrid type on soil nematode communities. The proportional representation of cp-1, cp-2 and cp-3-5 groups of nematode fauna indicated conditions of low stability and high stress. Faunal profiles representing the structure and enrichment conditions of the soil food web showed an environment with a high C:N ratio and high levels of fungal feeders. Based on the calculation of the metabolic footprint of nematodes in the soil food web, a difference between the isoline maize variant and Bt maize variant in 2012 was found, but this difference was not readily apparent in 2013. The occurrence of nematodes, their abundance, proportion of feeding types and selected ecological indices did not depend on the type of maize hybrid (Bt or non-Bt). Thus, the cultivation of genetically modified maize did not directly influence nematode populations. The application of fertiliser at certain periods does not influence the nematode community. The observed significant higher abundance of nematodes was correlated with soil moisture.

Nematodes (Nematoda) in Polish Forests. I. Species Inhabiting Soils of Nurseries

The paper presents the results of the analysis of 472 soil samples collected in the 1986-1987 time period, from 209 forest nurseries located in different regions of Poland. In total, 119 species of nematodes belonging to 56 genera were found: 64 species considered as plant feeders - parasites of higher plants, 34 species classified as fungal, epidermal cell and plant root hair feeders, 12 species of predatory nematodes, 2 species of omnivorous and 6 species of bacterial feeders. The most frequent species was Aphelenchus avenae which occurred in 45% of samples, followed by Paratylenchus projectus 22%, A. saprophilus 21%, A. bicaudatus 20%, P. pachydermus 20%, Trichodorus sparsus 20%, Aphelenchoides composticola 18%, A. parietinus 18%, Pratylenchus crenatus 17%, Bitylenchus dubius 14%, and P. penetrans 11%. Several species were very abundant e.g. maximal population density (number of specimens in 200 cm 3 of soil) of Cephalenchus hexalin- eatus was 3,180 individuals, of A. saprophilus 2,500 individuals, of Filenchus nemorosus 2,450 specimens, of Ditylenchus anchilisposomus 850 individuals, of Meloidogyne hapla 800 individuals, of Coslenchus costatus 560 individuals, of B. dubius 410 specimens, and of Roty- lenchus robustus 400 specimens. Nematode communities very poor in omnivorous and predatory species indicated that soil quality in the forest nurseries was very low. Such a finding means that seedlings could be less resistant to parasites and pathogens. The obtained results indicated that P. penetrans, R. robustus and species belonging to the family Trichodoridae could inhibit the growth of seedlings in nurseries.

Fatty acid composition and dynamics of selected fungal-feeding nematodes and fungi

Fatty acid profiles of fungal-feeding nematodes, Aphelenchus avenae and Aphelenchoides composticola, and selected fungi were determined in microcosm cultures of agar, broth, or sand amended with organic matter. Fatty acids of A. avenae and A. composticola included 16:0 18:0, 18:1ω7, 18:1ω9, 18:2, 20:0, 20:1, 20:2, 20:3 and 20:4 phospholipid fatty acids (PLFAs) and neutral lipid fatty acids (NLFAs). The nematodes differed in relative amounts of saturated and C 18 fatty acids. Similar C 16 and C 18 PLFAs and whole-cell fatty acids were found in Rhizoctonia solani, Fusarium oxysporum and Trichoderma sp. with 18:2ω6 as the major component. The C 20 fatty acids were not found in these fungi. Although only present in the nematodes, C 20 PLFAs were only detected when nematode population levels were ≥22 per gram of sand, suggesting that there is a detection threshold that might limit their use as biomarkers in the soil community. After removal of nematodes from a food source, the relative amount of C 20 PLFAs (structural components of nematode cell membranes) decreased more slowly than the C 16 and C 18 PLFAs, which may have reflected ingested fungal cytoplasm in the nematode intestine. In the early stage of organic matter decomposition, total and fungal PLFAs were lower in the presence of A. composticola then in its absence at C:N ratios ≥30:1.

Effect of temperature on growth and nitrogen mineralization of fungi and fungal-feeding nematodes

Dish and column microcosms containing alfalfa-sand medium were established to determine effect of temperature on growth and N mineralization ability of two fungi (Rhizoctonia solani and Botrytis cinerea) and two nematodes (Aphelenchus avenae and Aphelenchoides composticola). The microcosms were incubated at 15, 20, 25 and 29 ◦ C for 21 days. In the dish microcosms, hyphal growth rates of both fungal species increased with temperature in the range of 15–25 ◦ C. Above that temperature range, the growth rate of R. solani remained almost constant while that of B. cinerea decrease considerably. The population growth rate of A. avenae increased with temperature between 15 and 29 ◦ C on colonies of R. solani and B. cinerea in dish microcosms. The growth rate of A. composticola also increased in the range of 15–25 ◦ C but decreased greatly beyond that temperature range independent of the fungal species as food source. Inorganic N (NH4 + +N O 3 − ) was collected from each column microcosm by leaching every 3 days. In the columns containing R. solani, there was a significant effect of temperature on the amount of N detected in the fungus+A avenae or A. composticola but not in the fungus alone columns. The total amount of N was greatest at 29 ◦ Cf orA. avenae and at 20 ◦ Cf orA. composticola columns, concurrent with the population growth rates of the nematodes. In the columns containing B. cinerea, the effect of temperature on the amount of inorganic N was not significant in either the fungus alone or fungus+nematode columns, although the population growth rates of the both nematode species were highest at 20 ◦ C. For B. cinerea, the N amount across temperatures was the same or larger for the fungus alone as for the fungus+nematode columns. In general, the contribution of fungal-feeding nematodes to N mineralization was small in any combinations of fungus and nematode species at any temperature. Similarity in C/N ratio of the fungal and nematode biomass, organic substrate C/N ratios too low for measurable increase in net mineralization by the nematodes and small reproduction of the nematodes in the column microcosms were probable contributory factors.

Effects of leaf‐matter incorporation on Aphelenchoides composticola (Nematoda), mycofloral composition, mushroom compost quality and yield of Agaricus bisporus

SummaryIncorporation of dried leaves of Azadirachta indica, Cannabis sativa, Eucalyptus tereticornis and Ricinus communis at 3 kg per 100 kg of dry wheat straw prior to composting had several effects. When compared with controls, treated composts exhibited a higher temperature during composting, a higher nitrogen content and a neutral pH. The treatments resulted in enhanced populations of thermophilic fungi and mesophilic antibiotic‐producing fungi, but reduced numbers of mesophilic competitor/pathogenic moulds. Populations of the mycophagous nematode, Aphelenchoides composticola were reduced below economic injury level in dried leaf treated composts.Compost obtained from C. sativa and R. communis treatments were more rapidly colonised by the mushroom mycelium (Agaricus bisporus) than that from any other treatment. When compared with compost treated with carbofuran R. communis, C. sativa and A. indica treatments significantly increased mushroom yield by 19.4, 8.1 and 6.5% and by 108.5, 88.7 and 85.9% when compared with the control. Yield from the E. tereticornis treatment was also higher than the control but lower than that of the nematicide treatment.

Control of Aphelenchoides composticola in mushroom compost with nematicides

SUMMARYMushroom compost was treated with nematicides and infested with Aphelenchoides composticola at the time of filling into growing containers. Yields of mushrooms from infested untreated control composts were reduced to 40–60% of yields from uninfested control compost. Yields from infested compost treated with fenamiphos emulsifiable concentrate (e.c.) at 10 or 20 mg a.i./kg, thiabendazole wettable powder at 40 or 60 mg a.i./kg or oxamyl granules at 20 mg a.i./kg were as high as from uninfested controls. Compost treated with granules of AC 64,475 up to 20 mg a.i./kg or ethoprophos or thionazin up to 80 mg a.i./kg gave yields significantly lower than uninfested controls.Numbers of nematodes rose to about 106/20 g of compost in untreated compost and then fell, and a similar peak occurred in treatments in which yields were substantially reduced by nematode damage. Treatments which yielded as well as the uninfested controls held maximum nematode numbers down to about 10V20 g of compost but populations stayed at this level or tended to rise while numbers in untreated compost fell. Incorporation of fenamiphos in casing or its application to the surface of beds 3 wk after cropping began gave lower yields than the uninfested control but mushrooms were being produced late in the cropping cycle.Fenamiphos e.c. at 20 mg ai./kg incorporated in compost is considered a practical preventive measure for control of A. composticola.

Sexual anomalies in a female intersex of a species of Aphelenchoides (Nematoda: Aphelenchoididae)

A sterile intersex of a mycophagus species of terrestrial nematodes, identified as Aphelenchoides composticola, is described and the phenotypic characteristics illustrated. The body, tail, and reproductive system are female in character. The only male sexual structures evident are well-developed, paired spicula. The intersex differs from all other female intersexes in having an underdeveloped gonad, gonoduct, and postuterine sac and may represent a further transition in intersexuality. Characteristics of the germ cells of the intersex, compared with those in females, indicate that maturation had been arrested. Analogies are proposed for other female intersexes of the Tylenchida and Dorylaimida.

Suppression of Aphelenchoides Composticola and Ditylenchus Myceliophagus On Agaricus Bisporus By Thiabendazole and Benomyl

The effectiveness of thiabendazole and benomyl for control of Aphelenchoides composticola and Ditylenchus myceliophagus on Agaricus bisporus was investigated in vitro. Thiabendazole at 2.5, 5, 10 and 20 ppm and benomyl at 5, 10 and 20 ppm inhibited multiplication of the nematodes over 3 weeks and prevented degeneration of the mycelium. Thiabendazole at concentrations up to 20 ppm did not significantly reduce growth of A. bisporus but benomyl at 10 and 20 ppm reduced colony diameter significantly. Nematodes were not killed by direct contact with or direct uptake of the chemicals. It is suggested that either the nematodes acquire a toxic dose or toxic derivatives from the host or the chemicals act by suppressing reproduction and development at concentrations which do not kill.

Carbon Dioxide and the Hatch of Eggs and Development of Larvae of Aphelenchoides Composticola and Ditylenchus Myceliophagus

The minimum oxygen concentration for the optimum hatch of eggs of Aphelenchoides composticola was 1.5 % and for Ditylenchus myceliophugus, 2 %. This result probably reflects the difference in the size of eggs of each nematode rather than a difference in the affinity for oxygen of the enzymes at the sites of terminal oxidation in each species. The maximum rate of development of both nematodes occurred at concentrations of oxygen greater than 5 %. The ecological implications of the higher requirement for oxygen for development of larvae than for hatch of eggs are obscure. The increased demand for oxygen during development may occur because of the greater energy requirements of the larvae and adults. Evidence from this study supports a hypothesis that a cytochrome system is involved in the respiration of these nematodes. Results also indicate that concentrations of oxygen sufficiently low to prevent hatch of eggs or subsequent development of larvae will occur only in scattered, localised sites in most arable soils.

Oxygen and the Hatch of Eggs and Development of Larvae of Aphelenchoides Composticola and Ditylenchus Myceliophagus

Oxygen and the Hatch of Eggs and Development of Larvae of Aphelenchoides Composticola and Ditylenchus Myceliophagus

Gametogenese Et Determinisme Du Sexe Chez Le Nematode Mycophage Aphelenchoides Composticola

The cytological study of Aphelenchoides composticola gametogenesis shows that the diploid chromosome number is 4 A XX in females and 4 A XO in males. Hence, in this mycophagous gonochoristic nematode, the chromosomal sex determination is a Protenor type one. Irregularities in the duplication of one heteropycnotic chromosome, in some nuclei, during premeiotic stages of spermatogenesis, can explain the quantitative difference found in the adults and the fact that the females outnumber the males (tertiary sex ratio 0,7). These irregularities tend to produce a majority of spermatozoa with 3 chromosomes (2 AX) which will give only females, after amphimixis with ootids having a constant number of 2 AX chromosomes.

Some effects of the nematodes Ditylenchus myceliophagus and Aphelenchoides composticola on the yield of the cultivated mushroom

SUMMARYThe addition of one, ten and fifty Aphelenchoides composticola per ioo g compost at spawning reduced the total yield of sporophores by 26%, 30% and 42% respectively (P= 0·01), demonstrating a significant regression (P= 0·05) of yield on inoculum concentration.In pots inoculated at spawning with ten and fifty A. composticola per 100 g compost, cropping ceased after 12 weeks. The addition of twenty, 100 and 300 Ditylenchus myceliophagus at casing reduced the total yield of sporophores by 50%, 68% and 75 % respectively (P= 0·01). Cropping did not occur in pots inoculated at spawning, but continued for 9 weeks in pots inoculated at casing. The yield from pots inoculated at casing with either nematode was significantly greater (P= 0·05) than that from pots inoculated at spawning.When inoculated at spawning, peak populations of D. myceliophagus and A. composticola were reached 7 and 13 weeks, respectively, after spawning. Then the numbers present were unrelated to the number in the inocula.

The effect of some microphagous saprobic nematodes on mushroom culture

SUMMARYWhen added to spawned mushroom compost the microphagous saprobic nematodes Pelodera cylindrica, Mesorhabditis spiculigera and Acrobeloides bütschlii did not affect mycelial growth or compost pH. The eelworms multiplied at first but their numbers declined as the mycelium colonized the compost. In contrast, the fungal‐feeding Aphelenchoides composticola increased rapidly and destroyed the mycelium. Excess water, and the presence of the fungal competitor of mushroom, Chaetomium olivaceum, allowed some increase of the microphagous forms. Different numbers of Mesorhabditis spiculigera added to the ‘casing’ had no effect on mushroom yield but the mushroom ‘flushes’ seemed less pronounced. Reasons for the failure of the saprobic eelworms to affect mushroom, and the possibility of synergistic pathogenicity by these eelworms and bacteria, are discussed.

Some Effects of Ditylenchus Myceliophagus and Aphelenchoides Composticola On the Growth On Agar Plates of the Cultivated Mushroom, Agaricus Bisporus

Mycelium of Agaricus bisporus grew more rapidly on malt peptone agar at 25° C than at either 15°, 20° or 30° C. Similarly at 25° C, Aphelenchoides composticola reproduced more rapidly than at either 15°, 20° or 30° C. The rate at which mycelium was destroyed was similar for A. composticola and Ditylenchus mycellophagus but varied with the inoculum level of the nematode. About 1,000 A. composticola or 4,000 D. myceliophagus per plate was critical, and when these levels were exceeded rapid degeneration of the mycelium occurred. Regardless of the inoculum level, the number of A. composticola present in cultures after 28 days was the same and this also applied to cultures inoculated with D. myceliophagus. About five times as many D. myceliophagus as A. composticola were present on plates after 28 days. This difference is probably accounted for by differences in the number of eggs produced by the females.

Occurrence of Aphelenchoides Composticola Franklin in Mushroom Compost From New South Wales

Aphelenchoides composticola was found in mushroom compost from three places in New South Wales in association each time with reduced cropping. Measurements of the nematodes are given and a within-population variation in tail tip is illustrated. Specimens from two populations fed and reproduced rapidly on mushroom mycelium growing on agar in petri dishes.

OBSERVATIONS ON THE EFFECTS OF THE PARASITIC NEMATODES DITYLENCHUS MYCELIOPHAGUS, APHELENCHOIDES COMPOSTICOLA AND PARAPHELENCHUS MYCELIOPHTHORUS ON THE GROWTH AND CROPPING OF MUSHROOMS

The parasitic nematodes Ditylenchus myceliophagus, Aphelenchoides composticola and Paraphelenchus myceliophthorus severely damage mushroom mycelium and, in great numbers, reduce or even prevent cropping. The relationships between fluctuation of nematode population, state of the mycelium, duration of cropping and the yield of mushrooms are illustrated in a series of figures.