Interactions of Pratylenchus penetrans and Meloidogyne incognita as Coinhabitants in Tomato.

Greenhouse experiments on the interactions of Pratylenchus penetrans and Meloidogyne incognita showed that the population densities of both nematode species were depressed whenthey coinhabited tomato roots. Fifty days after inoculation, the population level of a P. penetrans monoculture was about four times higher than when M. incognita was present. Conversely, M. incognita reproduced twice as fast alone as in combination. There were no significant differences in the numbers of P. penetrans when they were inoculated either 10 days prior to or after introduction of M. incognita. Root entry by P. penetrans was significantly inhibited by the presence of M. incognita. Split-root experiments showed that the inhibitory effects of M. incognita upon reproduction of P. penetrans involved factors other than the availability of feeding sites. On the other hand, the inhibitory effects of P. penetrans on M. incognita appeared to be primarily due to the quantity of available roots.