The Influence of Some Environmental and Cultural Conditions On Rearing Populations of Xiphinema and Longidorus1)

Trials were carried out with hand-picked populations of Xiphinema spp. and Longidorus spp. to determine the effect of different environmental and cultural conditions on the nematode multiplication rate. Using Longidorus africanus as a test organism, a four-fold population increase within 5 months was recorded in polyethylene bottles as compared with that in clay pots; population build-up of L. africanus, Xiphinema brevicolle, X. diversicaudatum, X. index, and X. italiae in polyethylene bottles was quicker in a heavy than in a light soil. The increased multiplication rates were attributed to the smaller moisture fluctuations in the polyethylene containers and the heavier soil. Population build-up of X. brevicolle, X. index, X. italiae and L. brevicaudatus was quicker, and the duration of their life cycles was shorter, with increasing temperature levels between 16 and 28°C. Soil drenches with a nutrient solution at a normally recommended concentration were found to suppress drastically populations of L. africanus, while foliar sprays with a number of pesticides had no adverse effect. Attempts to introduce a single plant variety as a standard host in cultures of Xiphinema and Longidorus spp. were unsuccessful. Among the nematodes successfully cultured to date, the Longidorus spp. appear to have a shorter life cycle than the Xiphinema spp. X. mediterraneum and all the bisexual species of the two genera tested so far, have failed to thrive well in artificial cultures.