The aim of this project is to quantify the yield risk associated with planting CMV infected lentil seed in the Southern region. To do this, field experiments were conducted in key lentil growing areas over 2 years. This was done by:

• determining the impact of sowing different levels of CMV-infected seed on:
  • Disease progress throughout the season
  • Grain yield
  • Subsequent incidence of virus level in harvested seed for all treatments.
• Assessing the rate of CMV transmission via seed for different lentil cultivars, and
• Investigating lentil varietal susceptibility to CMV infection

The long-term outcome of this project is to reduce the levels of plant viruses such as CMV and minimise yield losses resulting from these plant pathogens in cropping systems in south-eastern Australia.

Following are some generalisations that can be used by growers based on the risk matrix:

1.       An effective control strategy for growers is to plant lentil cultivars that are resistant to CMV infection.

2.       An effective control strategy for growers is to sow lentil seeds with zero levels of CMV infected seed.  In this scenario the only source of CMV inoculum is from migratory aphids moving from CMV infected alternate hosts onto the lentil crop, and for this infection event to happen early in the growing season to have a negative impact on lentil yield.

3.       There is a moderate risk to growers to plant lentil seed with 1% CMV infection for moderately resistant, tolerant or moderately susceptible lentil cultivars, while susceptible cultivars will have a measurable reduction in yield.  These impacts will be influenced by the abundance of aphid vectors in the crop, particularly early in the season. 

4.       There is a major risk to growers to sow tolerant, moderately susceptible or susceptible cultivars of lentil with 2-3 % infection levels of CMV in seed at sowing.

5.       There is a major risk to growers to sow moderately resistant, tolerant, moderately susceptible or susceptible cultivars of lentil with greater than 3% infection levels of CMV in seed at sowing.

Informed management strategies driven by the Risk Matrix guide will have a long-term outcome of reducing the levels of, and yield losses resulting from, the viral disease caused by CMV in the lentil cropping system.