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The impact of increasing temperatures on the population dynamics of the soil‐dwelling nematode Globodera pallida, a persistent and economically important pest of potatoes, was investigated. The reproductive factor (final population⁄initial population) and length of life cycle were found to be temperature sensitive. Pot experiments performed over 4 months allowed comparison of the effect on development of G. pallida of two temperature regimes: an average temperature comparable to current field conditions (14.3 °C) and an average temperature above current field conditions (17.3 °C). A larger second generation of juveniles was observed at 17.3 °C compared to 14.3 °C. Multiplication of G. pallida at field sites in Shropshire and East Lothian (average soil temperatures of 15.5 and 14.1 °C, respectively, during potato cropping) was also examined. A quantitative PCR assay and visual examination of roots were used to monitor the dynamics of the G. pallida populations in both field sites at 4‐weekly intervals. Four cultivars, Desirée, Cara, Maris Piper and Estima, were grown with and without nematicide treatments. Nematicide treatments suppressed population increases at both sites. Females were observed on the roots of cvs Cara and Desirée at the end of the growing season in Shropshire, but not at East Lothian, and are likely to represent a second generation. [ABSTRACT FROM AUTHOR]

A system to grow tomato plants infected by Meloidogyne javanica under constant temperatures of 18, 21, 24, 27 and 30 °C was developed and used to assess how temperature and the application of the biological control bacterium Pasteuria penetrans affected plant growth, the nematode population and endospore production. Each plant was inoculated with 300 second‐stage juveniles (J2) with four or five spores of P. penetrans attached to their cuticles or with 300 nematodes without P. penetrans. Increasing soil temperature increased tomato growth, the number of endospores per female, and the number of galls of M. javanica at the end of 38 days. Increasing temperatures up to 27 °C also increased the number of egg masses produced by M. javanica. Presence of P. penetrans reduced the numbers of galls and egg masses at all temperatures by up to 52.2% and 61.4% at 27 and 30 °C, respectively. Pasteuria penetrans reduced the M. javanica population even at soil temperatures of 18 and 21 °C. However, temperatures of 27 and 30 °C enhanced nematode control and the production of P. penetrans endospores is faster. The system developed in this work is simple and efficient for growing plants under constant temperatures and can be used for different purposes. [ABSTRACT FROM AUTHOR]

Dagger and needle nematodes included in the family Longidoridae (viz. Longidorus, Paralongidorus, and Xiphinema) are highly polyphagous plant-parasitic nematodes in wild and cultivated plants and some of them are plant-virus vectors (nepovirus). The mitochondrial (mt) genomes of the dagger and needle nematodes, Xiphinema rivesi, Xiphinema pachtaicum, Longidorus vineacola and Paralongidorus litoralis were sequenced in this study. The four circular mt genomes have an estimated size of 12.6, 12.5, 13.5 and 12.7 kb, respectively. Up to date, the mt genome of X. pachtaicum is the smallest genome found in Nematoda. The four mt genomes contain 12 protein-coding genes (viz. cox1-3, nad1-6, nad4L, atp6 and cob) and two ribosomal RNA genes (rrnL and rrnS), but the atp8 gene was not detected. These mt genomes showed a gene arrangement very different within the Longidoridae species sequenced, with the exception of very closely related species (X. americanum and X. rivesi). The sizes of non-coding regions in the Longidoridae nematodes were very small and were present in a few places in the mt genome. Phylogenetic analysis of all coding genes showed a closer relationship between Longidorus and Paralongidorus and different phylogenetic possibilities for the three Xiphinema species. [ABSTRACT FROM AUTHOR]