Optimize Sugar Beet Revenue – Varieties With a Good Mildew Profile Can Contribute

Research over recent years has shown that, even in the absence of significant disease, an application of a triazole or strobulurin fungicide helps to delay leaf senescence and increase yields  by 4 – 5%.  The more ‘open’ the autumn is,  the greater the benefits are likely to be.

Some people make just one application in August, this makes sense on crops destined to be lifted early in the campaign. Others may apply a second treatment later in the season and the benefit of this is debatable. As the days shorten and the overnight temperatures drop so the amount of extra growth per day declines. However, the beet still needs protection from rust and mildew and the August treatments are only likely to last around 6 weeks even if applied at full doses.

In the crops destined for late lifting you have two options:

- Apply a second fungicide spray at a cost of perhaps £18/ha plus application costs of around £9/ha – total cost £27/ha.

- Plan ahead and sow a variety with a good disease resistance profile which could save you the cost of the second fungicide treatment.

KWS varieties have some of the best disease resistance ratings on the list. The table below lists the NIAB/BBRO 1-9 resistance ratings for the 2009 varieties and gives the mean of the other varieties on the list. 

Most varieties seem relatively resistant to rust but the benefit of KWS UK varieties in terms of resistance to mildew is clear.

Brooms Barn acknowledges that this is the disease most likely to rob you of up to 20% yield, particularly if it establishes early in the season. Currently the best combination of high yields and mildew resistance are MANDELLA (104.1% adj. tonnes) and the rhizo-resistor SOPHIA (103.6% adj. tonnes).

 

Disease ratings of KWS UK varieties and the

mean of the market varieties for 2008.

Data Source: NIAB/BBRO *1-9 rating where 1 = very susceptible and 9 = very resistant

Variety	Rust*	Mildew*
MANDELLA	7	7
DOMINKA	7	7
ACE	8	9
JUSTINA	7	4
SOPHIA	6	7
CARISSIMA	5	2
ANEMONA	5	8
Mean of other varieties	6.2	4.0

Most KWS UK varieties have good mildew resistance thus they are not likely to gain a significant benefit from a second fungicide application even when lifted late. This could be a point that you consider when making your variety decisions for the forthcoming 2009 season. It is well worth looking into all aspects of your variety choice to fully optimize your crop.