How variety choice could help reduce damage from cabbage stem flea beetle
Posted 6 years ago
26/03/2020
Varieties that develop more rapidly in the autumn and earlier in the spring seem able to substantially reduce damage from cabbage stem flea beetle larvae as well as adults, according to the latest variety trials Agrii.
“We have undertaken almost 40 specific flea beetle management trials since 2009,” points out seed technical manager, David Leaper.
“It’s crystal clear from the whole range of approaches we’ve explored that no single one offers a reliable solution. It’s equally clear that anything that gets in the way of early crop growth can significantly increase flea beetle impact.
“We’ve long found the fastest developing varieties in the autumn are better able to grow away from adult flea beetle grazing as well as coping more effectively with later sowing and more challenging establishment conditions,” he reports.
“Across more than 40 varieties on four sites significantly affected by flea beetle in 2018/19, we also saw a very good correlation between the level of larval damage and speed of autumn development (Figure 1).”
Interestingly, the Agrii trials further showed the earliest varieties to grow away in the spring suffered the least stunting and main stem loss from flea beetle larvae (Figure 2). Like the advantage enjoyed by faster developing varieties in the autumn, Mr Leaper puts this down to their superior ability to compensate through earlier growth and development.
Fast-developing varieties, DK Exsteel and DK Expedient stood out in the trials in both these respects. Even faster-developing in the autumn and very early to resume growth in the spring, DK Extremus promises to add to their advantages in combatting the flea beetle threat.
At the same time, the fastest-developing Clearfield varieties like DK Impressario CL have been showing a clear establishment edge for their tolerance to ALS inhibitor residues when grown in reduced tillage systems.
Figure 1:
Figure 2:
