黄瓜绿斑驳花叶病毒随病残体在土壤中越冬越夏后的致病性OA

Cucumber green mottle mosaic virus(CGMMV)is an important agricultural quarantine pathogen in China.Infection by CGMMV poses potential soil health risks due to virus persistence in plant debris.To determine the survival duration of CGMMV in soil,clarify whether the virus can overwinter and oversummer with infected plant debris under natural conditions in different regions,and assess its potential as a primary inoculum source for subsequent crop,soil extracts containing diseased plant debris were prepared.The pathogenicity of residual virus under different debris-to-soil mass ratios(1.3％,3％,and 6％)was evaluated using mechanical inoculation assays and soil transmission experiments.Under non-overwintering conditions,mechanical inoculation of watermelon with soil extracts at a debris-to-soil ratio of 1.3％resulted in a maximum disease incidence of 86.7％,whereas a ratio of 6％consistently caused 100％disease incidence.Correspondingly,soil transmission rates at debris-to-soil ratios of 1.3％,3％,and 6％were 0,1.5％,and 10.7％,respectively,indicating that virus accumulation in soil must reach a threshold level to enable transmission.In Nanning,Urumqi,and Zhengzhou,soil samples containing 6％diseased plant debris exhibited disease incidence rates of 26.67％,35.33％,and 26.67％,respectively,in watermelon following mechanical inoculation with soil extracts,with soil transmission rates of 2.00％,1.33％,and 1.67％.After overwintering and oversummering,disease incidence decreased to 4.00％,2.00％,and 2.67％,respectively,and soil transmission capacity was almost completely lost.These results indicate that CGMMV can overwinter and oversummer with infected plant debris in cucurbit-producing regions across different latitudes in China and can serve as a primary inoculum source for subsequent cucurbit crops.However,the pathogenicity of residual virus in soil gradually decreases over time.