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The generation time and reproduction of Meloidogyne incognita was studied under five soil temperatures. The life cycle was completed on tomato between average soil temperatures of 16.2°C and 30.0°C but not at 35.4°C. On the marigold(Tagetes hybrid) variety Polynema the life cycle was completed only at 30.0°C. Estimates for the base temperature (Tb) and the required heat sum (S) were 10.1°C and 400°C. day respectively. The thermal time relationship for completion of the life cycle of M. incognita is discussed in relation to those of other Meloidogyne species. Influence de la temperature sur la duree du cycle biologique d'une population de Meloidogyne incognita - La duree du cycle et la reproduction de Meloidogyne incognita ont ete etudiees a cinq temperatures. Sur tomate, le cycle peut s'accomplir a des temperatures moyennes du sol s'etageant de 16,2 a 30,0°C, mais non a 35,4°C. Sur oeillet d'Inde (hybride de Tagetes de la variete Polynema), le cycle ne s'accomplit qu'a 30,0°C. La temperature de base (Tb) et la demande thermique (S) sont estimees a, respectivement, 10,1°C et 400°C/jours. La relation temperature/temps relative a l'accomplissement du cycle biologique est discutee et comparee au cas des autres especes du genre.

SummaryVirus transmission bait tests with single trichodorid nematodes from England, the Netherlands, Scotland or Sweden showed that a substantial degree of specificity occurs between trichodorid vector species and tobravirus serotypes. This specificity was more apparent with associations between Paratrichodorus vector species and tobravirus serotypes than with those between Trichodorus species and tobravirus serotypes. P. pachydermus transmitted PRN‐serotype tobacco rattle virus (TRV) isolates, P. teres ORE‐serotype isolates and P. anemones TRV isolates which did not react with any of the antisera used, but which could be distinguished from all other isolates by their symptomatology in Chenopodium test plants. T. viruliferus, T. primitivus and T. cylindricus transmitted RQ‐serotype isolates and the latter species also transmitted TRV isolates reacting with TCB2 and pea early‐browning SP5‐antisera. Several TRV isolates transmitted by T. cylindricus failed to react with any of the antisera used.

Scutellonema spp. are widely distributed across tropical and subtropical regions of the world and are associated with numerous agricultural and horticultural crops. Identification of many Scutellonema species is not always reliable, in part because many species share very similar diagnostic characters. In this study, we provide morphological and molecular characterisation of S. brachyurus from the USA and South Africa, S. bradys from Nigeria and three unidentified species from California, USA, New Zealand and Burkina Faso. Morphological descriptions, measurements, light and scanning electron microscopic photos and drawings are given for S. brachyurus. Females of S. brachyurus from the USA (type A) and South Africa (type B) showed a significant variation in the number of sectors and blocks on the lip annuli, ranging from about 4-12 and from 8-20, respectively. Molecular analysis using the D2-D3 of 28S rRNA, ITS rRNA and the COI mtDNA gene sequences revealed two distinct genotypes within S. brachyurus samples: type A (samples from USA, Italy, Korea, Taiwan) and type B (South Africa). Multivariate analyses determined that S. brachyurus from the USA and Taiwan (type A) differed from that from South Africa (type B) mainly in body, tail and DGO lengths, and ratios b′, c′, c and V. Phylogenetic relationships within Scutellonema are given as inferred from the analyses of the D2-D3 of 28S rRNA, ITS rRNA and the COI mtDNA gene sequences. PCR-RFLP diagnostic profiles and PCR with species-specific primers are developed for the studied Scutellonema species.