Further to the information on whitefringed weevil in PestFacts Issue No. 6, NSW Department of Primary Industries is investigating the possibility of links between whitefringed weevil and damage to sub-surface irrigation systems. Senior Research Entomologist, Adrian Nicholas, reports that some lucerne growers are experiencing damage to their sub-surface irrigation pipe work and this does occur where whitefringed weevil larvae are in high numbers.
The damage consists of rasping/pincering of the piping until a hole is worn through. This damage could be made by whitefringed weevil larvae, however this has not yet been confirmed.
There is a minor use permit (PER8972) valid for use only in NSW until 30 September 2007, allowing Chlorpyrifos to manage whitefringed weevil adults on emergence in lucerne. Depending on the region, this is between December and early May. A copy of the permit is available at http://www.apvma.gov.au/permits/permits.shtml.
Whitefringed weevil management in lucerne and, in particular lucerne grown over sub-surface irrigation systems is the subject of ongoing research by the Field Crop Entomology Unit at the Tamworth Agricultural Institute. For further details contact Adrian on (02) 6763 1283 or email: Adrian.Nicholas@dpi.nsw.gov.au.