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Abstract Background The nematode phylum includes many species key to soil food webs with trophic behaviours extending from feeding on microbes to macrofauna and plant roots. Among these, the plant parasitic cyst nematodes retain their eggs in protective cysts prolonging their survival under harsh conditions. These nematodes, including those from the genus Heterodera, cause significant economic losses in agricultural systems. Understanding of nematode diversity and ecology has expanded through application of genomic research, however, for Heterodera species there are very few available whole genome sequences. Sequencing and assembling Heterodera genomes is challenging due to various technical limitations imposed by the biology of Heterodera. Overcoming these limitations is essential for comprehensive insights into Heterodera parasitic interactions with plants, population studies, and for Australian biosecurity implications. Results We hereby present draft genomes of six species of which Heterodera australis, H. humuli, H. mani and H. trifolii are presently recorded in Australia and two species, H. avenae and H. filipjevi, currently absent from Australia. The draft genomes were sequenced from genomic DNA isolated from 50 cysts each using an Illumina NovaSeq short read sequencing platform. The data revealed disparity in sequencing yield between species. What was previously identified as H. avenae in Australia using morphological traits is now confirmed as H. australis and may have consequences for wheat breeding programs in Australia that are breeding for resistance to H. avenae. A multigene phylogeny placed the sequenced species into taxonomic phylogenetic perspective. Genomic comparisons within the Avenae species group revealed orthologous gene clusters within the species, emphasising the shared and unique features of the group. The data also revealed the presence of a Wolbachia species, a putative bacterial endosymbiont from Heterodera humuli short read sequencing data. Conclusion Genomic research holds immense significance for agriculture, for understanding pest species diversity and the development of effective management strategies. This study provides insight into Heterodera, cyst nematode genomics and the associated symbionts and this work will serve as a baseline for further genomic analyses in this economically important nematode group. more...

Cyst-forming nematodes have been known since the second half of the 19th century as one of the causes of "soil fatigue" and highly harmful agricultural pests. In Ukraine, the sugarbeet cyst nematode Heterodera schachtii Schmidt, 1871; cereal cyst nematode H. avenae Wollenweber, 1924; golden potato cyst nematode Globodera rostochiensis Wollenweber, 1923; clover cyst nematode H. trifolii Goffart, 1932; alfalfa cyst nematode H. medicaginis Kirjanova & Krall, 1971; hop cyst nematode H. humuli Filipev, 1934 are currently economically significant species. Their distribution mainly coincides with the traditional cultivation of sugar beets, grain cereals, potatoes, clover, alfalfa and hops. Long-term studies of the impact of abiotic, biotic, and anthropogenic factors on their populations made it possible to identify the dominant species and improve the set of protective measures. Anti-nematode crop rotations are the main limiting factor in preventing mass reproduction of cyst-forming nematodes, provided there is scientifically justified crop rotation. To prevent the mass accumulation of alfalfa and clover cyst-forming nematodes, the maximum share of perennial grasses in crop rotations should not exceed 30% (crops under cover of grain cereals + perennial legumes – one-two-year use); oat nematode – 40% of grain cereals; beet nematode – 20% of Chenopodioideae and cruciferous crops; golden potato nematode – 20% of potatoes (10% susceptible + 10% resistant varieties). The rational saturation of modern crop rotations with intermediate crops makes it possible to reduce the level of crop weediness caused by potential host plants of cyst-forming nematodes and to increase their anti-nematode effectiveness in general. The developed ecologically oriented system of phytosanitary control provides mandatory measures, which must be applied regardless of the level of initial population density, and additional measures specific to each culture and species of cyst-forming nematodes. Considering the current high specialization of crop production, the use of biological preparations in modern systems of integrated plant protection will contribute to the greening of agricultural output. Pre-planting treatment of tubers with metabolic biological preparations (Streptomyces avermitilis) of multifunctional action ensured the achievement of a higher (79.2–91.7%) efficiency of biological cleaning of the soil from the golden potato nematode, compared to the use of only potato-resistant varieties. A logical combination of various anti-nematode measures makes it possible to effectively keep the density of populations at an economically insignificant level and prevent crop yield losses. more...

The identification and phylogenetic relationships of potato cyst nematodes (PCN) were studied to assess the potential value of geographical distribution information for integrated pest management of potato production in Portugal. This research focused on PCN species, Globodera pallida and Globodera rostochiensis. From 2013 until 2019, 748 soil samples from the rhizosphere of different potato cultivars were surveyed in the Portuguese mainland to detect and identify both species and track their location. PCN are widespread invasive species throughout Portugal. In fact, during the survey period an incidence of 22.5% was estimated for the tested samples. The patterns of infestation vary among regions, increasing from south to north, where PCN were first detected. Currently, both species are present in all potato producing regions of the country, with a greater incidence of G. pallida. Phytosanitary control measures are influencing to the observed results. The use of potato cultivars resistant to G. rostochiensis led to a decrease of this species but had no influence on G. pallida detections, which continues its reproduction freely since there are no effective resistant cultivars for this species. The relationship between the presence, infestation rate, spread and geographical distribution of PCN is discussed in terms of behavioral responses of the potato cultivars and the implications for developing new integrated crop protection measures. more...

The species structure, morphological peculiarities and economic importance of the dominant cyst nematodes from cultural and natural phytocenosis of Ukraine are analyzed.

На Дальнем Востоке России отмечен 21 вид седентарных нематод из групп цистообразующих, галловых и тиленхулидных. 7 видов выявлено в агроценозах, 1 вид – в Ботаническом саду.

На Дальнем Востоке России отмечен 21 вид седентарных нематод из 2 надсемейств и 4 семейств – Heteroderidae, Melodogynidae, Tylenchulidae и Sphaeronematidae. Из группы цистообразующих нематод семейства Heteroderidae на Дальнем Востоке России известно 13 видов, из них 9 видов отмечено в естественных ценозах. В группе галловых нематод – 5 видов, из которых 2 вида встречаются в естественных ценозах. Два последних семейства включают в себя по 1 виду и на Дальнем Востоке отмечены только в естественных ценозах. more...

As nematodes cause great damage to Brazilian coffee production, effective methods to control these parasites are necessary. In a previous work Allium cepa L., Cajanus cajan (L.) Mill., Crotalaria juncea L., Ficus elastica Roxb., Ruta graveolens L., Stylosanthes guianensis Aubl., Leucaena leucocephala (Lam.) Dewit., Brachiaria decumbens Stapf., Catharanthus roseus G. Don, Tagetes minuta L., Ricinus communis L. and Coffea arabica L. produced active substances against Meloidogyne exigua Goeldi, a nematode widely disseminated through Brazilian coffee fields. Thus, aqueous extracts of such plants, collected in a different season from that of the previous work, as well as crude metabolites produced in liquid medium by Fusarium moniliforme Shelden and Cylindrocarpon magnusianum (Sacc.) Woll., were submitted to in vitro assays with M. exigua second-stage juveniles (J2). All plants and fungi produced active substances against J2. Therefore, their metabolites were applied to six-month-old coffee plants inoculated with M. exigua. After 90 days in a greenhouse, those samples obtained from A. cepa, L. leucocephala, R. graveolens and F. moniliforme inhibited the production of galls and eggs by M. exigua, demonstrating potential to control such parasite.Os nematóides acarretam grandes perdas aos produtores brasileiros de café, sendo necessário o desenvolvimento de métodos eficientes para o seu controle. Em trabalho anterior, Allium cepa L., Cajanus cajan (L.) Mill., Crotalaria juncea L., Ficus elastica Roxb., Ruta graveolens L., Stylosanthes guianensis Aubl., Leucaena leucocephala (Lam.) Dewit., Brachiaria decumbens Stapf., Catharanthus roseus G. Don, Tagetes minuta L., Ricinus communis L. e Coffea arabica L. produziram substâncias ativas contra o nematóide Meloidogyne exigua Goeldi, que é amplamente disseminado pelos cafezais brasileiros. Dando continuidade a esse trabalho, extratos aquosos das plantas mencionadas, coletadas em época diferente daquela mencionada no trabalho anterior, bem como metabólitos na forma bruta de Fusarium moniliforme Shelden e Cylindrocarpon magnusianum (Sacc.) Woll., produzidos em meio de cultura líquido, foram submetidos a testes in vitro com juvenis do segundo estádio (J2) de M. exigua. Todas as plantas e fungos produziram substâncias ativas contra J2. Portanto, seus metabólitos foram aplicados em mudas de café de seis meses de idade, inoculadas com M. exigua. Após 90 dias em casa de vegetação, verificou-se que os materiais oriundos de A. cepa, L. leucocephala, R. graveolens e F. moniliforme inibiram a produção de ovos e de galhas por M. exigua, demonstrando potencial para o controle de tal parasita. more...