Cabbage Stem Flea Beetle
Oil Seed rape crops are now established so Cabbage Stem Flea beetle are no longer a problem – True or False?
In reality adults are known to feed on plant stems as well as leaves. While flea beetles may not do much on wet days, on cool and windy ones they keep feeding. There is no set economic threshold for stem feeding, but if the stem is chewed through or leaf stalks are severed, leaf area loss will be 100%.
What about the larvae?
Adults lay their eggs in the soil around the young plants. Once they hatch they invade the oil seed rape plant. Here they feed, passing through 3 stages of growth (instars.)
With early drilled crops the attack starts in October and where severe results in plant death. Death is usually more severe where additional factors come into play such as pigeon grazing, adverse weather or simple herbicide up take.
Unlike many pests CSFB attacks tend to be uniform over the whole field. Therefore a great deal of searching is not usually required to detect the severity of this pest.