Occurrence of the Root-Knot Nematode Meloidogyne hapla in the Czech Republic

Meloidogyne hapla was detected in several commercial vegetable fields in the Province of Central Bohemia in the Czech Republic. Crops grown in the area of infestation include leek, onion, cauliflower, early potatoes, and carrot. During the past 2 to 3 years, growers have observed typical symptoms of Meloidogyne infection as stunting and galls on roots of carrot. Identification of the causal organism was based on microscopic observation of the perineal patterns of females obtained from root galls and polymerase chain reaction (1,2). Known isolates of M. chitwoodi, M. arenaria, M. javanica, M. incognita, and M. fallax from M. Phillips (SCRI, Dundee) and C. Zijlstra (PRI, Wageningen), and M. hapla from M. Liskova (PI, Kosice) were used as controls. M. hapla was identified in galled roots using both methods. Several fields with carrots were inspected in the area during vegetation in 2000 and 2001. In most fields, only isolated and limited outbreaks occurred, but recently, we observed a widespread and fairly homogeneous occurrence of root knot attributed to M. hapla in a 2-ha field. This nematode may become a more widespread and damaging pest, especially of carrot, in the Czech Republic. Other than carrot, vegetable crops grown in the area and tested in the greenhouse and field in soil highly infested by our isolates of M. hapla had no visible symptoms of infection. Therefore, exclusion of carrot cultivation or a longer crop rotation is recommended to minimize economic losses to growers. To our knowledge, this is the first report of the occurrence of M. hapla in the Czech Republic. References: (1) T. S. Harris et al. J. Nematol. 22:518, 1990. (2) C. Zijlstra et al. Genetics 85:1231, 1995.