INFLUENCE OF THE PREVIOUS CROP ON THE ANHYDROBIOTIC ABILITY OF PRATYLENCHUS THORNEI AND MERLINIUS BREVIDENS

Abstract

The influence of the previous crop on the anhydrobiotic survival of Pratylenchus thornei and Merlinius brevidens was investigated in a pot experiment with three different cultivars of wheat, sunflower, opium poppy and dwarf chickling as host crops. Nematodes were extracted from the soil after six months of plant growth and three months later, after a slow dehydration of soil and storage in dry conditions. A clear influence of the previous crop on the ability to survive the dry season was observed for both nematode species, since survival was significantly greater when nematodes were cultured previously on a good host crop, such as wheat cvs Yecora and Cajeme for P. thornei and wheat cvs Yecora, Cajeme and Donpedro or sunflower for M. brevidens. Densities of anhydrobiotic nematodes were also monitored in the field, for seven consecutive fortnights, after harvest of wheat cv. Yecora. Percentages of anhydrobiotic nematodes were always greater for P. thornei than for M. brevidens at every fortnight sampling and under the same soil conditions, indicating a greater anhydrobiotic ability of P. thornei.