Status nematoda korijenovih kvržica roda Meloidogyne u Hrvatskoj, s posebnim osvrtom na karantenske vrste

Root-knot nematodes of the genus Meloidogyne belong to the most economically important group of plant-parasitic nematodes and also to the most important plant pests that can cause significant economic losses in crop production. They are poly phagous, highly adapted, obligate endoparasites of nearly all higher plant species, including the important agricultural crops. Within the genus Meloidogyne, about one hundred species have been described, of which the four species-that is, the Meloidogyne incognita, M. arenaria, M. javanica, and M. hapla-are the important plant pests and the most widespread species worldwide. As of 2010, twenty-three species have been confirmed in Europe, of which three non-quarantine species have been detected in Croatia. Many nematode species of the genus Meloidogyne can be considered dangerous invasive pests in agriculture, as they can spread rapidly due to the global trade, changing production technologies leading to a reduced use of pesticides, and climatic changes. To prevent or to limit the introduction and spread of the three species of root-knot nematodes, Meloidogyne chitwoodi, M. fallax, and M. enterolobii, respectively, were entered in the European list of quarantine nematodes. The species M. mali is incorporated in the EPPO A2 quarantine list, in addition to the three aforementioned species, while the M. ethiopica, M. luci, and M. graminicola are on the EPPO Alert List. It is expected that the tropical Meloidogyne species, for instance the M. enterolobii, M. ethiopica, and M. luci, as well as the M. incognita, M. arenaria, and M. javanica, will become the important pests in the temperate zones due to the new,) climatic conditions, more favorable for their development, which can pose a huge risk to the agricultural production. In Croatia, a wide distribution of nematode populations of the genus Meloidogyne spp. was con firmed, but a scientific knowledge about the species identification is very modest. Due to the variety of soil and climatic conditions present in Croatia, it is expected that more Meloidogyne species than those that are known so far will be detected in the future. This is one of the reasons for starting a more intensive monitoring of the Meloidogyne species in Croatia too.Nematode korijenovih kvržica iz roda Meloidogyne pripadaju ekonomski najvažnijoj skupini biljnoparazitskih nematoda i jedne su od najvažnijih biljnih štetnika koji mogu uzrokovati značajne ekonomske gubitke u biljnoj proizvodnji. Oni su polifagni, dobro prilagođeni, obligatni endoparaziti gotovo svih viših biljnih vrsta, uključujući i važne poljoprivredne kulture. Unutar roda Meloidogyne opisano je oko stotinu vrsta, od kojih su četiri vrste, Meloidogyne incognita, M. arenaria., M. javanica i M. hapla, važni štetnici u biljnoj proizvodnji i najrašireniji u svijetu. Od 2010. godine u Europi su potvrđene dvadeset tri vrste, od čega su u Hrvatskoj otkrivene tri nekarantenske vrste. Mnoge vrste nematoda iz roda Meloidogyne mogu se smatrati opasnim invazivnim štetnicima u poljoprivredi jer se mogu brzo širiti zbog globalne trgovine, promjena tehnologija u proizvodnji koje dovode do smanjene upotrebe pesticida i klimatskih promjena. Kako bi se spriječilo ili ograničilo unošenje i širenje triju vrsta nematoda korijenovih kvržica, Meloidogyne chitwoodi, M. fallax i M. enterolobii uvrštene su na europski popis karantenskih nematoda. Vrsta M. mali uvrštena je na karantensku listu EPPO A2, uz tri navedene vrste, dok su M. ethiopica, M. luci i M. graminicola na popisu upozorenja (to jest na listi EPPO Alert). Očekuje se da će tropske vrste roda Meloidogyne poput M. enterolobii, M. ethiopica i M. luci, kao i M. incognita, M. arenaria i M. javanica, postati važni štetnici u umjerenim zonama zbog novih, povoljnijih (toplijih) klimatskih uvjeta za njihov razvoj, što može predstavljati velik rizik za poljoprivrednu proizvodnju. U Hrvatskoj je potvrđena velika rasprostranjenost populacija nematoda roda Meloidogyne spp., ali su znanstvene spoznaje o identifikaciji vrsta vrlo skromne. Zbog raznolikosti tla i klimatskih uvjeta prisutnih u Hrvatskoj, očekujemo da ćemo u budućnosti pronaći više vrsta roda Meloidogyne negoli je dosada poznato. To je jedan od razloga za početak intenzivnijega praćenja vrsta roda Meloidogyne u Hrvatskoj

First report of nematodes Parasitylenchus bifurcatus Poinar & Steenberg, 2012 parasitizing multicolored Asian lady beetle Harmonia axyridis (Pallas, 1773) in Slovenia

In years 2015 and 2016 around 200 specimens of ladybird species Harmonia axyridis were collected in Slovenia. Ladybirds were dissected and checked under stereomicroscope for presence of nematodes. Nematodes were discovered in samples of ladybirds H. axyridis collected at Brdo pri Lukovici and Trboje. The incidence of parasitized ladybirds was around 30 %. Nematodes were analysed morphometrically and the characteristic features of Parasitylenchus bifurcatus nematodes were observed: straight stylet lacking basal thickenings, a bursa and a forked tail tip in the vermiform females and juvenile males. The identity was confirmed with 18S rDNA region sequence (acc. no. LT629306 and LT629307) which showed high similarity (&gt;99.9 % nucleotide identity) to the P. bifurcatus sequences in the public domain. This is a first report of P. bifurcatus nematode species found parasitizing ladybird Harmonia axyridis in Slovenia. The species compromises fecundity of its host and has therefore a potential to be used as a biological control agent to control high abundance of invasive H. axyridis ladybirds.</em

Discrimination between abiotic and biotic drought stress in tomatoes using hyperspectral imaging

Crop plants are subjected to various biotic and abiotic stresses. Both root-knot nematodes (biotic stress) and water deficiency (abiotic stress) lead to similar drought symptoms in the plant canopy. In this work, hyperspectral imaging was used for early detection of nematode infestation and water deficiency (drought) stress in tomato plants. Hyperspectral data in the range from 400 to 2500 nm of plants subjected to different watering regimes and nematode infestation levels were analysed by partial least squares – discriminant analysis (PLS-DA) and partial least squares – support vector machine (PLS-SVM) classification. PLS-SVM classification achieved up to 100% accuracy differentiating between well-watered and water-deficient plants, and between 90 and 100% when identifying nematode-infested plants. Grouping the data according to the time of imaging increased the accuracy of classification. Shortwave infrared spectral regions associated with the OH and CH stretches were most relevant for the identification of nematode infested plants and severity of infestation. This study demonstrates the capability of hyperspectral imaging to identify and discriminate between biotic and abiotic plant stresses

From Genome to Field—Observation of the Multimodal Nematicidal and Plant Growth-Promoting Effects of Bacillus firmus I-1582 on Tomatoes Using Hyperspectral Remote Sensing

Root-knot nematodes are considered the most important group of plant-parasitic nematodes due to their wide range of plant hosts and subsequent role in yield losses in agricultural production systems. Chemical nematicides are the primary control method, but ecotoxicity issues with some compounds has led to their phasing-out and consequential development of new control strategies, including biological control. We evaluated the nematicidal activity of Bacillus firmus I-1582 in pot and microplot experiments against Meloidogyne luci. I-1582 reduced nematode counts by 51% and 53% compared to the untreated control in pot and microplot experiments, respectively. I-1582 presence in the rhizosphere had concurrent nematicidal and plant growth-promoting effects, measured using plant morphology, relative chlorophyll content, elemental composition and hyperspectral imaging. Hyperspectral imaging in the 400&ndash;2500 nm spectral range and supervised classification using partial least squares support vector machines successfully differentiated B. firmus-treated and untreated plants, with 97.4% and 96.3% accuracy in pot and microplot experiments, respectively. Visible and shortwave infrared spectral regions associated with chlorophyll, N&ndash;H and C&ndash;N stretches in proteins were most relevant for treatment discrimination. This study shows the ability of hyperspectral imaging to rapidly assess the success of biological measures for pest control