Sugarbeet growers in the UK could be seriously underestimating the extent and theimplications of Beet Cyst Nematode, warned Syngenta Technical Manager, JamesEvans.
Speakingat a BBRO Open Day at Bury St Edmunds recently, he advocated farmers whosuspect they have field with light to medium BCN problems should be growing thenew Syngenta variety, Maddox. This now offers yields very comparable to thebest performing beets on the recommended list, combined with tolerance to BCNpopulations.
Inthe past, growers have had to trade-off the risk of BCN yield loss fromaffected patches in the field, compared to a lower overall output from growinga BCN tolerant variety, advised Mr Evans. Now, with Maddox, we have a varietythat will yield well across the whole field, and mitigate losses in affectedareas.
Resultsof soil testing for pest pressure have tended to indicate around 10% of UK beetgrowing land is affected by BCN, yet less than 3% of UK seed sales arecurrently of varieties with any degree of nematode tolerance. Furthermore, MrEvans pointed out that, in practice, few soils are tested for pest presenceunless there has been a serious problem.
Ifgrowers adopted more intensive and regular soil testing programmes, it wouldreveal the true extent of the problem – and enable better management options.In Benelux and Holland, for example, soil sampling has highlighted a fargreater proportion of fields are affected, which is directly reflected in over20% of the area being planted with BCN tolerant varieties, he reported.
Oneof the problems is that BCN typically tends to be quite patchy across fields,making it difficult to identify and quantify the extent of infestations. Usingthe sampling methodology employed by potato growers to map Potato Cyst Nematodepopulations would be a positive approach, he advised.
MrEvans also suggested that beet growers could suffer similar issues to thepotato industry, where production has been concentrated into the hands of fewerfarms on more intensive regimes, and with seasonal weather conditions that havebeen more conducive to nematode survival.
Newon the 2015 sugar beet Descriptive List, Maddox is recommended by Syngenta forplanting where soil testing has identified light to medium BCN infestations. Itis most suited to drilling from 1 March in a typical growing season, but MrEvans pointed out that where BCN is recognised as a problem, dealing with thepest will always take precedence over drilling date.
Allthe indications are that BCN is likely to become a more serious issue that willneed to be managed more aggressively to maintain sustainable beet growingrotations in the future, he said. Maddox is a significant advance on previousSyngenta BCN tolerant varieties, and now gives the chance to produceconsistently high beet yields across the whole field.