Sensitivity of Venturia carpophila from China to Five Fungicides and Characterization of Carbendazim-Resistant Isolates.

Peach scab is a fungal disease caused by Venturia carpophila that can significantly reduce peach yield and quality. Fungicide application is the main control measure for peach scab worldwide. To better understand the fungicide-resistance status and devise suitable management strategies, the sensitivity of 135 single-spore V. carpophila isolates to the commonly used fungicides carbendazim, iprodione, propiconazole, azoxystrobin, and boscalid were determined using a microtiter plate test method. Results showed that the mean effective concentrations to cause inhibitions by 50% (EC50) of tested isolates to iprodione, propiconazole, azoxystrobin, and boscalid were 16.287, 0.165, 0.570, and 0.136 µg/ml, respectively. The EC50 values of V. carpophila isolates to four fungicides displayed unimodal frequency distributions, indicating no resistance occurred to these fungicides. On the contrary, bimodal frequency distribution was observed for carbendazim, indicating that V. carpophila developed resistance to carbendazim. Resistance was widely detected from all 14 provinces studied. Molecular analysis showed that the point mutation E198K of the TUB2 gene determined high resistance, whereas E198G conferred moderate resistance. Moderate and high resistances were stable, and the resistant isolates did not show significant fitness penalties. On the contrary, some resistant isolates showed better competitiveness under certain stresses. This is the first report to detect the sensitivity of V. carpophila to fungicides, which enables future monitoring of fungicide resistance and provides basic information to allow the design of suitable peach scab management strategies.

[Impact of low-frequencies noise on the ability of thinking and judgment].

Three typical low frequency noise samples which were collected from some associated facilities in urban residential areas and white noise which was produced by acoustic apparatus were selected to compare the competence of brainwork index (AYP) and error rate in noisy environment with those in quiet environment, using dosage exercise method. The result indicates that AYP is lower in noisy environment and the error rate is higher than that in quiet environment, and there are significant differences between them. The changes of most testees in groups that use three different low frequency noise samples respectively are more obvious than the group that uses white noise, and the AYP difference attains significant level. It indicates that low frequency components are the main frequency elements to affect the ability of thinking and judgment. By paired samples t-test and frequency spectrums analysis, the results show that the impact degree of air condition outdoor unit noise is highest, and noise samples which have a peak frequency between 50-300 Hz have a more negative impact on the ability of thinking and judgment than other environmental noise.