Title : Epidemiology and control of emerging viruses in protected horticulture
Abstract:
he cultivation of solanaceous and cucurbits crops is of great economic importance in Spain, and most of the production is located in in the south-east part of the country. Tomato leaf curl New Delhi virus (ToLCNDV) is an important bipartite begomovirus that affects crops belonging to the family of Cucurbitaceae (melon, watermelon, squash, and cucumber) and Solanaceae (tomato and pepper), it was first described in India in 1995 but gradually also in other parts of Asia. It is transmitted by the whitefly Bemisia tabaci and produces puckering, distortion, curling, vein clearing and yellow green mosaic in leaves. In Spain, a new strain of ToLCNDV was detected during the summer of 2013, causing an outbreak especially in commercial squash fields and afterwards in other cucurbit crops such as melon and cucumber. In Solanaceae crops such as tomato, the virus caused mild symptoms but its presence has to be considered as a source of inoculum. Cucumber green mottle mosaic virus (CGMMV) belongs to the genus Tobamovirus, family Virgaviridae. It is transmitted by contact and causes systemic mottle and mosaic symptoms on leaves and fruits of cucumber, melon and watermelon. CGMMV was first described infecting cucumber in England in 1935. In Spain, it was first detected in the 1990´s in cucumber crops in the province of Almeria but its incidence has increased during the last five years, being responsible for small outbreaks in cucumber and watermelon crops. CGMMV isolates are grouped in two clusters based on biological differences and genome sequences: a first cluster constitutes the European strain, and a second one is formed by isolates from Asian countries. Spain is actually the first country where both strains are present, co-infecting the same crops and in the same region. Until now, no commercial plants with effective resistance to ToLCNDV and CGMMV are available by the growers. To control the ToLCNDV disease, measures were directed to control the virus vector. Today, the control of CGMMV disease depends on the correct management crops that includes the correct disinfection of working tools, which can transmit the virus during the crop cutting and pruning, as well as protocols that determine the movements of ordinary and specialized workers. This work was supported by project AVA2019.015 from IFAPA and FEDER.
