Jolanta Kowalska

Pesticide residues determination in Polish organic crops in 2007-2010 applying gas chromatography-tandem quadrupole mass spectrometry.

A sensitive, accurate and reliable multiresidue method based on the application of gas chromatography-tandem quadrupole mass spectrometry (GC-QqQ-MS/MS) has been established for screening, identification and quantification of a large number of pesticide residues in produce. The method was accredited in compliance with PN-EN ISO/IEC 17025:2005 standard and it was operated under flexible scope as PB-11 method. The flexible scope of accreditation allowed for minor modifications and extension of the analytical scope while using the same analytical technique. During the years 2007-2010, the method was used for the purpose of verification of organic crop production by multiresidue analysis for the presence of pesticides. A total of 528 samples of differing matrices such as fruits, vegetables, cereals, plant leaves and other green parts were analysed, of which 4.4% samples contained pesticide residues above the threshold value of 0.01 mg/kg. A total of 20 different pesticide residues were determined in the samples.

Evaluation of yeast-like fungi to protect Virginia mallow (Sida hermaphrodita) against Sclerotinia sclerotiorum

Abstract Virginia mallow is a plant from the central and eastern states of North America. A large amount of high quality biomass obtained from V. mallow led to interest in this plant for bioenergy purposes. Unfortunately, high incidence of white rot disease caused by Sclerotinia sclerotiorum destroyed plantations of this plant. In previous attempts, various control strategies were not successful and all treatments failed (including the use of Coniothurium minitans). The aim of the study was to find and evaluate yeast-like fungi for biocontrol of S. sclerotiorum, evaluate the optimal thermal condition for biocontrol efficacy, and describe possible modes of action of potential biocontrol organisms. In dual bioassay test with 19 strains of yeast-like fungi with S. sclerotiorum, antagonistic potential were obtained. At different temperatures variations in antagonistic activity of yeast-like fungi were observed. At all tested temperatures (i.e., 4, 12, and 23°C), positive results were obtained. Extracellular enzymes were produced by the majority of antagonistic yeast, such as: amylases (the most frequent), chitinases, proteases, pectinases and xylanases. In this research, reduction in white rot symptoms on V. mallow stems was significant (P < 0.05). The highest inhibition of disease was observed after treatment with strains (114/64) Candida albidus and (117/10) Pichia anomala.