The importance of tropical root-knot nematodes (Meloidogyne spp.) and factors affecting the utility of Pasteuria penetrans as a biocontrol agent Trudgill, D.L. Bala, G. Blok, V.C. Daudi, A. Davies, K.G. Gowen, S.R. /Fargette, Mireille Madulu, J.D. /Mateille, Thierry Mwageni, W. /Netscher, Caspar Phillips, M.S. Sawadogo, A. Trivino, C.G. Voyoukallou, E. NEMATODE PHYTOPARASITE CULTURE MARAICHERE INFESTATION METHODE DE LUTTE LUTTE BIOLOGIQUE BACTERIE SOL PROPRIETE PHYSICOCHIMIQUE SYSTEME DE CULTURE RELATION HOTE PARASITE ETUDE COMPARATIVE The conclusions of a collaborative study of the occurrence and importance of root-knot nematodes (RKN, Meloidogyne spp.) and of their control agent, Pasteuria penetrans, in parts of Europe, Africa, South America and the Caribbean are presented. Root-knot nematodes were estimated to reduce the yields of a wide range of horticultural crops by greater than 25% in Ecuador, Malawi and Tanzania, and by ca 10% in Trinidad and Tobago. The greatest proportion of infected crops were observed in Ecuador (205 of 207) and the least in Trinidad and Tobago (70 of 174). The mean gall index was greatest in Ecuador (5.5). Levels of galling were least in Senegal (1.6), even though 89% of crops were infested and virulent M. mayaguensis was widespread. In all countries, M. incognita and M. javanica were the most abundant species, but M. hispanica occurred widely in Burkina Faso, even in newly cultivated areas in the Sahile. Several new esterase phenotypes were detected, especially in Ecuador and Malawi. Juveniles (J2) collected from the soil during the surveys were examined for attached spores of P. penetrans. It was widespread (20 to 60% of RKN populations), except in Malawi and Tanzania (less than 10% were infected), and was found for the first time in Crete (Greece). Generally, less than 50% of the J2 carried spores. The occurrence of P. penetrans was sometimes correlated with soil type e.g., in Senegal it was least frequent in sandy soils. Laboratory assays of the binding of spores of isolates of P. penetrans to populations of RKN were sometimes almost as great as those between species. In microplot trials in which an "exotic" isolate of P. penetrans was introduced (ca 10(sup 3) spores per g soil), its incidence was not increased by increasing the frequency or intensity of the growing of RKN-susceptible crops... (D'après résumé d'auteur) 2000 text https://www.documentation.ird.fr/hor/fdi:010024957 fdi:010024957 Trudgill D.L., Bala G., Blok V.C., Daudi A., Davies K.G., Gowen S.R., Fargette Mireille, Madulu J.D., Mateille Thierry, Mwageni W., Netscher Caspar, Phillips M.S., Sawadogo A., Trivino C.G., Voyoukallou E.. The importance of tropical root-knot nematodes (Meloidogyne spp.) and factors affecting the utility of Pasteuria penetrans as a biocontrol agent. 2000, 2 (8), 823-845 EN EUROPE AFRIQUE AMERIQUE DU SUD CARAIBE SENEGAL BURKINA FASO EQUATEUR MALAWI TANZANIE TRINITE ET TOBAGO