Investigating the timing of transmission of carrot viruses to improve management strategies

Summary: All crops, agricultural, horticultural and ornamental, are affected by virus-like diseases, although the causal agents of such diseases may not be known. Where disease does occur the level of economic damage may not be great enough to warrant investigation of treatment regimes. Plant viruses are transmitted by vectors including invertebrate, fungal or human.  Once a plant is infected with a virus it cannot be treated and will form a source of inoculum for other plants. Gaining an in-depth knowledge of the epidemiology of plant virus diseases is the key to effective disease management. With the decrease in availability of pesticides for the horticultural industry alternative approaches such as novel chemistries and cultural management can be expensive to apply prophylactically or may only be allowed with a limited number of applications. Therefore, the primary elements to understanding effective virus management become identification of key vectors and the timing of transmission to formulate management strategies. Work will be carried out in the carrot crop system to investigate the timing, sources, and key vectors of viruses known to cause economic crop losses.

Aim: The aim of the project is to provide an end to end approach to viral disease management. This will include identification, measurement of incidence and impact of viral pathogens, and methods to investigate the timing, sources and vectors of virus diseases in horticultural crops, leading to more effective approaches to virus management.

Objectives:

1) Vector management – assessing the relative importance of different vector species and the timing of transmission of the key viruses, Carrot red leaf virus (CtRLV) and Carrot yellow leaf virus (CYLV), into carrot crops.
2) Sources of virus – with a focus on CYLV carry out a limited population study on isolates of the virus to see if population phylogenetics can identify the source of infections in carrot crops.
3) Further development/refinement of aphid forecasting systems and improved interpretation of monitoring data.
4) Initial trialling of improved management strategies.