Pea yellow top virus disease: pea yellow top disease caused by pea yellow top virus, the top leaves of the diseased plant yellowing, shrinking, wrinkled and curled, brittle leaves, plant shrinking, not flowering and fruiting, and finally formed a bush branch, the plant died. Transmission method: aphid persistent transmission. Sap, soil and seeds are not transmitted. Transmission mediator: bean aphid Aphis. craccivora. persistent transmission, minimum feeding time 3h, cycle period 7h, minimum inoculation time 15min, can not be transmitted to the offspring. The transmission rate of single-head aphids can reach 66% to 68%.