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DCA Publikationer Meadow-grass Gall Midge DCA rapport, nr. 5, 2012 Af Lars Monrad Hansen  The area with meadow-grass (Poa pratensis, L.) grown for seed production in Denmark is a significant proportion of the entire seed production. The meadow-grass gall midge (Mayetiola schoberi, Barnes 1958) is of considerable economic importance since powerful attacks can reduce the yield drastically. It overwinters as larvae in a puparium, in the soil, and begins to hatch on average in late April, but the time is depending on the temperature. Emergence of the meadow-grass gall midge in spring takes place over a 2-3 week period.
Beginning of emergence of the meadow-grass gall midge takes place after the puparies have obtained 114 ± 21 day-degrees calculated from January 1st, with a biological development zero at 5 °C. The top of the flying curve achieves after 179 ± 29 daydegrees. With this information, the farmers can fairly accurately spray just before the flight curve has its maximum. Therefore, the spraying frequency could be lowered significantly and in many cases lowered to only one insecticide application in meadow-grass every year. |