Fusarium species, zearalenone and deoxynivalenol content in preharvest scabby wheat heads from Poland

Abstract

High incidence of Fusarium head blight occurred in Northern and Southern Poland in the 2009 season. Head samples from 106 wheat fields were collected before harvest from Northern, Central and Southern Poland in August 2009. Fusarium species were identified in 1,311 heads with visible scab symptoms and the collected material was subjected to mycotoxin analyses. Fusarium graminearum was identified as the most frequently occurring species on wheat, present in 48% of all samples examined. This species prevailed in Northern and Southern Poland, with the frequencies of 53% and 55%, respectively, and its frequency has increased over five-fold after two decades. In the central part of the country, Fusarium culmorum was the major pathogen of wheat, with a frequency of 43%, although in this region the incidence of infected heads in wheat fields was lower than 1%. Several other species, including Fusarium avenaceum, Fusarium cerealis and Microdochium nivale, occurred with lower frequencies. Microscopic identification of species was confirmed using species-specific markers in DNA extracted directly from sporodochia. For the first time, glucosylated deoxynivalenol was identified in Polish cereals, in amounts of 1.6 to 7.4 mg/kg. Deoxynivalenol (DON) content was estimated between 1.7 and 11.9 mg/kg for the healthy looking kernels (HLK) fraction, while the Fusarium-damaged kernels (FDK) were contaminated with high amounts of DON, from 57.3 to 312.3 mg/kg, and zearalenone, from 0.035 to 4.48 mg/kg. The HLK fractions contained about 20 times less DON and zearalenone (ZEA) than the FDK fractions. ZEA accumulated in both FDK kernels and chaff fractions at a similar level. DON was accumulated in the chaff fraction in much lower amounts than in the FDK fraction.