No abstract

The Colletotrichum musae and Fusarium semitectum Berk., Which often occur in banana after harvest were used as the targets. Three components with antibacterial activity extracted from the leaves of the plant were used as "fungicide". The antibacterial effect of the three component substances on the pathogens of anthracnose and shaft rot was studied. The results showed that the inhibitory rates of the components A, B and C at 2 mg / ml on the pathogens of banana anthracnose and shaft rot reached 82.53%, 79.91%, 78.30% and 82.2%, 78.69% and 81.17% respectively. The EC90 values of component A, B and C for banana anthracnose pathogens were 1.70, 1.85, and 1.69 mg / ml. Respectively, the EC90 values for banana shaft rot pathogens were 1.37, 1.38, and 1.64 mg / ml. The antibacterial effect of the three component substances on the pathogen of banana shaft rot was better than that of anthracnose. The three component substances have great potential for controlling post-harvest anthracnose and shaft rot of bananas.

Spirotetramat is a potential tetronic acid pesticide for controlling various pests with piercing–sucking mouthparts. To clarify its dietary risk on cabbage, we established an ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method and then investigated the residual levels of spirotetramat and its four metabolites in cabbage collected from field experiments under good agricultural practices (GAPs). The average recoveries of spirotetramat and its metabolites in cabbage were 74~110%, while the relative standard deviation (RSD) was 1~6%, and the limit of quantitation (LOQ) was 0.01 mg kg−1. The terminal residue of spirotetramat was in the range of <0.05~0.33 mg kg−1, the chronic dietary risk (RQc) was 17.56%, and the acute dietary risk (RQa) was 0.025~0.049%, which means an acceptable dietary intake risk. This study provides data to guide on the use of spirotetramat and to establish the maximum residue limits (MRLs) of spirotetramat on cabbage.