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Population densities, population fluctuations, yield loss and disease incidence caused by Nacobbus aberrans on tomato (Lycopersicon esculentum) were studied, using an epidemiological approach, in a field experiment that included three different control regimes: an integrated control (IC) scheme, which included fertilisation, nematicide (ethoprop) and chicken manure; a technical control (TC) scheme, based on the best local practices of fertilisation and use of carbofuran for nematode control; and a check treatment (AC), with no application of fertilisers or nematicide. At least three generations of N. aberrans occurred through the cropping season and the numbers of galls/plant and females/g of root through the crop season were used to define the area under a disease progress curve (AUDPC). The variables b-1 (Weibull's apparent infection rate), AUDPC and Yf (final disease incidence) indicated less crop damage under the IC scheme than under the other two schemes (TC and AC). The IC scheme resulted in increased plant height (41-49%), foliage dry weight (37-53%) and stem diameter (31-41%) compared with the TC and AC schemes. Tomato yields in IC surpassed those from TC and AC by 34 and 83%, respectively, while TC exceeded AC by 73%. The yield loss attributed to N. aberrans was 12, 29 and 83% in IC, TC and AC, respectively. The IC scheme improved commercial production by 20 and 81% in comparison to the TC and AC schemes. This was largely due to effective control of the initial inoculum density, which affects the first generation of the nematode population; control of this generation is essential for avoidance of yield loss. The first generation is completed during the period 0-60 dat (days after transplanting), i.e., during the critical stages of flowering, fruit initiation and fruit set (40, 50 and 60 dat). Data on plant performance taken every 10 days were used to derive a multiple point model for calculation of production loss. [ABSTRACT FROM AUTHOR]

Populations of potato cyst nematode (PCN) were assembled from all of the potato growing regions of Portugal, either by direct sampling of fields or from cyst samples sent to the University of Coimbra for identification. When 30 or more cysts were available, isoelectric focusing of species-specific protein bands was used to identify which PCN species were present. PCN was present in 35% of a set of 226 soil samples. PCN was also identified in a larger set of 423 populations. Of the 423 populations, 83% were pure Globodera rostochiensis, 8% were pure G. pallida and 9% were mixtures of the two. PCN was found in all of the main potato growing areas but G. pallida was not detected in Coimbra, Setúbal or Viana do Castelo districts. [ABSTRACT FROM AUTHOR]

Twelve populations of Nacobbus aberrans from Mexico and South America were cultured in the glasshouse on tomato plants. Second stage juveniles, males, young females and mature females were recovered from the cultures and studied using light microscopy. Morphometric data were analysed using canonical variate analysis. Many of the characters previously used to establish species or subspecific ranks were shown to be variable and all variants occurred in all populations studied, even if at low frequencies. Etude morphometrique de douze populations de Nacobbus aberrans (Thorne, 1935) Thorne & Allen, 1944 (Nematoda: Pratylenchidae) du Mexique et d'Amerique du Sud - Douze populations de Nacobbus aberrans du Mexique et d'Amerique du Sud ont ete elevees en serre sur plants de tomate. Les juveniles de deuxieme stade, les males, les femelles jeunes et les femelles matures ont ete recoltes a partir de ces elevages et etudies en microscopie photonique. Les donnees morphometriques ont ete analysees par analyse canonique. De nombreux caracteres precedemment utilises aux niveaux specifique ou subspecifique sont apparus variables, tous les variants etant presents dans toutes les populations etudiees, a des frequences parfois faibles mais jamais nulles. [ABSTRACT FROM AUTHOR]

The article presents an obituary for plant nematologist Brian Kerry.