As the cotton season draws to a close it is time to for the DAFF team working on Silverleaf whitefly (SLW) resistance monitoring to start making collections of whitefly from across the cotton-growing regions.
Even if SLW numbers are below threshold, it is possible for the team to make collections of either nymphs (on leaves) or adults (using the suction machine). We are currently looking for fields with SLW in any of the cotton-growing valleys to include in the screening for insecticide resistance.
Because the cotton industry is so reliant on 1-2 insecticides to control SLW, it is important that the any changes in the susceptibility of the populations be detected early. Every season since 2008, DAFF has been screening SLW populations in laboratory bioassays to determine if there is any evidence of resistance developing to pyriproxyfen (Admiral®), diafenthiuron (Pegasus ®) bifenthrin (Talstar®), and more recently spirotetramat (Movento®).
To date, there has been no change detected in the susceptibility of SLW field populations from cotton-growing regions.
Watch the video to see how the field sampling is done and get a glimpse of a bioassay underway in the lab.