Risk Factors

BCN propagation as a function of crop rotation. Source: modified acc. to Steudel

Soil types: BCN survive in all soils but thrive in those that are warm and moist. Higher temperatures will encourage a greater number of breeding cycles within each crop. So it is no surprise that most positive tests for BCN in the UK are found on light mineral and peat soils.

Rotation:

Overseas experience shows us that beet grown one in three years will increase the BCN population.  Beet grown one in four years will maintain the population and one in five years will see a decrease in the population over time.

Host Plants:

The hosts that pose the greatest risk are the from the brassica family and more specifically oil seed rape which is both a host and multiplier of BCN and is a common crop in most sugar beet growing areas.

Spread:

BCN movement is slow and natural migration is limited. Therefore, spread between fields is largely as a result of cultivation and machinery movement. Wind erosion also favours spread of the pest. BCN are not transferred with processed seed .