CSFB larvae for the chop
Strong autumn root growth and healthy plants has given the opportunity to try a new cultural technique to break the Cabbage Stem Flea Beetle life cycle and potentially reduce pest pressure for the autumn.
In November some plots on the iOSR Focus Site were mechanically chopped back to remove leaf stems and petioles containing the CSFB larvae; other plots will be cut back later in the season, before spring growth, reported Syngenta Field Technical manager, James Southgate.
He told iOSR growers that the crops will be assessed for the effects on the numbers of beetles and impacts on yield.
“With reduced options to control Flea Beetle in the autumn, it’s an opportunity to try something radical on a small plot basis - which could have real implications to tackle an issue on a field scale,” he claimed.
The technique would appear to favour varieties that are more prostrate in autumn and winter growth, where the growing tip is safely protected whilst the leaves are cut back.
“There will also be an effect from the spring vigour of some varieties, for both the timing of any treatment and the speed of recovery," pointed out James (below).
“The key will be if we can get crops to the desired GAI of 3.5 at flowering,” he added.
“Over the course of a few seasons we could assess which crops respond effectively and how to manage them accordingly.”
Whilst the defoliation would remove nutrients taken up by the crop over the autumn, they would be recycled and available for following crops – potentially also encouraging beneficial earthworm activity for longer thorough the season.
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