Identification and characterization of Ditylenchus spp. populations from garlic in New York State, USA

Abstract

Ditylenchus dipsaci is an important pathogen of onion and garlic and causes reductions in bulb quality. Between 2012 and 2014, 345 garlic bulb samples were tested for Ditylenchus spp. The average incidence of Ditylenchus spp. was 14.1 %. Twenty-five individuals from 31 Ditylenchus spp. populations were selected for identification by morphology, species-specific PCR, and sequencing of the ITS1-5.8S-ITS2 region. Thirty populations were identified by morphology and species-specific PCR as D. dipsaci. Sequencing of the ITS1-5.8S-ITS2 region of the ribosomal DNA found the populations were 99.7 to 100 % similar to each other, and 99.3 to 100 % similar to other D. dipsaci reference isolates from France, and California, USA. One population was identified as Ditylenchus sp. and was 97 % similar within the ITS1-5.8S-ITS2 region to D. destructor. This information will be useful for the monitoring of future pest outbreaks in garlic in New York State, USA, and the effectiveness of management recommendations.