Big catch of beetles this season

Press, 3 April 1980, Page 10

Big catch of beetles this season

A record number of grass grub beetles were caught in light traps at Winch--, more irrigation research station in Mid-Canterbury . tfiis' -sea.son. •; ■ -.' < j> According to Mr J. Wood, a technical officer, at‘the station, this cer-. ; tainly means that there is a potential for serious ..damage .to .pastures this ; winter, .but he is- not prepared to say categorically that this will eventuate,'for he adds that there is a great deal that goes on that they .do.npt.know about.- ' The station has ; been trapping the beetles since

1963. Two light traps are used — • the beetles -are *. attracted -by . ultra violet light. . .... .The trapping goes on . from the? .last week in October through to the first week in January, -with the ■ peak period being the last week in November. This season the aggregate of beetles caught in the L ' ; tw,QT traps was an impres- ' sive- 260,892. The previous tally was in the 1976-77 season at-slightly in excess of 204,100. The lowest was in the . first season back in 1963? when ■ only -482 trapped. Mr

Wood observes that' the trend has been for numbers to build up. Following the previous big catch in 1976-77, Mr Wood says that there-was quite a lot of damage topastures but not as much as expected. After that, in the following two seasons prior to the build up again this season, the trappings dropped to 26,500 and 20,800. Once numbers get to high levels cannobilism develops and there -- is greater susceptibility to disease. “Once they get to a certain stage (of population) they seem to foul their. <o.wri.' nests,”; i’commented Mi>£Wqod, •