Population density of Heterodera trifolii Goffart in Southern Chile pastures

Abstract

Presence of Heterodera trifolii was surveyed in 18 permanent pastures at the IX and X regions of Chile to evaluate its population. The nematode cysts were extracted with a Fenwick can extraction equipment; later they were processed using a maceration technique to examine its content of eggs and juveniles. Clover cyst nematodes were recorded in all sampled sites, the average number was 47,6 cyst per 100 cc of soil, the predominant form being collapsed and broken cysts. The average number of eggs and juveniles varied between 31 and 320, with at least 50% viable propagules. The naturalized condition of this pest was confirmed considering its wide distribution in permanent pastures of both regions.