[Differences of bacterial and fungal communities in the tree and rhizosphere of the healthy and twig blight-diseased bayberry]. / å¥åº·ä¸Žå‡‹èŽç— æ¨æ¢ æ ‘ä½“åŠæ ¹å›´èŒç¾¤çš„å·®å¼‚.

Twig blight is a serious disease of bayberry, which limits bayberry production. In order to prevent and manage the disease, we used high-throughput sequencing technology to analyze bacterial and fungal community richness and diversity in various organs of the tree, bulk and rhizosphere soil of healthy and diseased bayberry. The results showed significant differences in richness and diversity of bacteria and fungi in bulk soil, rhizosphere soil, roots, trunks, barks, and leaves between twig blight diseased trees and healthy trees. In bulk soil, the richness and diversity of bacteria significantly decreased, while that of fungi significantly increased. In barks of diseased trees, the richness and diversity of bacteria significantly increased, and those of fungi significantly decreased. The relative abundance of dominant bacteria and fungi in various organs, bulk soil, and root surface soil changed significantly at phylum, class, and genus levels in the diseased trees. The relative abundance of Pseudomonas sp. on the trunks, roots, and root surface soils of diseased trees significantly decreased, and Fusarium sp. of the diseased root surface and bulk soils also significantly decreased, while the relative abundance of Penicillium sp. on the diseased root surface and bulk soils significantly increased. Pestalotiopsis sp., from the same genus as the twig blight pathogen, was less abundant in the roots but more abundant in the leaves, trunks, barks as well as root surface soils and bulk soils of the diseased bayberry trees than those of the health trees. The relative abundance of Pestalotiopsis sp. was positively correlated with those of most of the fungi. Our results might provide useful theoretical basis for the development of ecological improvement and healthy-tree cultivation technology, and biological control of bayberry twig blight disease.

Residual behavior and risk assessment of prochloraz in bayberries and bayberry wine for the Chinese population.

The bayberry is an important economic fruit as well as a minor crop in China, and few pesticide products are registered for bayberry. Prochloraz is a widely used fungicide with a high detection rate on bayberry. This study evaluated the potential dietary risk of prochloraz for different populations in China based on field trial data and market surveillance. The results indicate that one-time applications at dosages of 1000 and 1500 mg/kg with a recommended preharvest interval of 20 days do not pose a chronic or acute dietary risk. However, applying the above dosages twice will cause a potential short-term dietary risk. Risk assessment results conducted on surveillance samples indicated acceptable long-term risks for the general population, with a hazard quotient < 0.82. Furthermore, simulated washing and wine production processes were performed to mimic household practices to investigate residue transfer and distribution. We found that rinsing with tap water for 1 min was an effective way to remove residue, and the processing factors of prochloraz for both bayberry and wine were < 1, indicating that wine production could reduce residue levels. Prochloraz had a strong capacity to transfer to wine due to its high log Kow value, with transfer percentages up to 43%. This study supports the recommendation on good agricultural practices for prochloraz application and provides a guide for safe consumption.