青风藤叶枯病病原菌的分离鉴定及防治药剂的筛选

2021年春季，从湖南省怀化市中方县正清制药青风藤基地和湖南农业大学试验基地分别采集青风藤叶枯病病叶，利用组织分离法获得病原菌，并进行柯赫氏法则验证。借助形态学鉴定和分子系统学分析，明确青风藤叶枯病病原为交链隔孢(Alternaria alternata)。利用菌丝生长速率法对5种药剂(95%苯醚甲环唑、98%咪鲜胺、96%己唑醇、96.5%丙硫菌唑、98%嘧菌酯)进行筛选，结果显示95%苯醚甲环唑抑菌效果最好，EC₅₀为0.043 6 mg/L;98%嘧菌酯抑菌效果最差，EC₅₀值为8.447 3 mg/L。     

Improved management of mango fruit though orchard and packinghouse treatments to reduce lenticel discoloration and prevent decay

Mango fruit are exposed to complex postharvest handling management, intended to improve postharvest quality retention during export shipment. Susceptibility to lenticel discoloration and to Alternaria side rots and Phomopsis stem-end rot under current handling conditions led us to re-evaluate and modify the chain of postharvest treatments, from the orchard to the packinghouse. The previously developed hot-water brushing (HWB) treatment was found effective in reducing incidence of Alternaria and stem-end rots, but it significantly induced development of red lenticels. Two factors were key to improving fruit quality, by simultaneously reducing lenticel discoloration and decay development: (a) postharvest water and/or NaOH washes in the orchard, and (b) hot-water spray (HWS) applied over rollers without brushes in the packinghouse. The present results indicate that optimal management involves combinations of water washes in the orchard with packinghouse HWS treatment; this significantly reduced the severity of lenticel discoloration by 50–60%, and the incidence and extent of postharvest side rots caused by Alternaria by 60% or more. These results indicate that appropriate handling of fruit can appreciably improve their quality during prolonged storage and shipment.