Last season was a somewhat low pressure year for silverleaf whitefly (SLW) in all cotton districts. The low pressure may have been attributed in part to high rainfall especially through central Queensland which does not favour whitefly population build up. St George and Mungindi districts still reached densities that exceeded the recommended insecticide spray thresholds although they generally fitted into… Read more »
Outlined in today’s blog are the results for whitefly parasitism assessments, whitefly species composition and whitefly resistance testing from the 2009-2010 cotton season.
We have fielded numerous enquiries this week from consultants who would like to assess levels of whitefly parasitism. This is achievable in the field with the use of a hand lens. Parasitism levels appear to be a little down from last year, but still good levels have been recovered. Parasitism so far has ranged from 50-90% in Emerald, 35% in… Read more »
We have received numerous enquiries about whitefly in the last week especially from the MacIntrye and Lower Namoi areas. Shortages of chemicals to control whitefly is currently of major concern to many growers and consultants in this region. Many enquiries also relate to species identification. Whitefly samples identified from the MacIntyre and Lower Namoi areas have been 100% B biotype… Read more »
There are reports of large infestations of silverleaf whitefly (SLW) from the Narrabri/Moree region. Exponential growth in whitefly numbers coupled with honeydew on leaves indicates that the whitefly are probably SLW and not East Australian native Bemisia or Greenhouse whitefly (GHW). It is thought that increased host plant availability from a wet winter/spring, warm conditions and a decline in natural… Read more »
Silverleaf whitefly (SLW) is a serious pest of cotton. It reduces yield and quality of cotton due to feeding damage and excretion of honey dew. It is a difficult pest to manage due to its ability to rapidly increase in numbers and the development of resistance to many insecticides. Resistance testing for the 2007-08 season indicated no alarming results for… Read more »
In the last week, reports from the Downs are suggesting that silverleaf whitefly (SLW) numbers have increased rapidly, and now there are a number of fields that have a population at or exceeding the treatment threshold. This posting has been compiled from information and discussion with Richard Sequeira (Principal Entomologist, Emerald) and Paul Grundy (Senior Entomologist, Ayr) who have considerable… Read more »
Reports of increasing numbers of whitefly are filtering in from across the Downs. In some cases, numbers are sufficient to suggest that control of Silverleaf Whitefly (SLW) may be warranted. Correct identification and regular monitoring of populations is essential to determine if intervention is necessary. Which whiteflies are out there? Results of whitefly samples identified from Downs cotton crops… Read more »
There is an increasing number of reports of whitefly in cotton crops on the Downs. Typically, whitefly start appearing in crops in mid to late summer, once populations have built up on weed hosts or other host crops (e.g. sunflower) adjacent to cotton crops.So far this season we have been able to make collections of whitefly adults and immatures (scale)… Read more »
On Friday August 10, St George growers and agronomists met to discuss strategies to manage the Silverleaf whitefly population in the irrigation area. Over the past two seasons, a number of cotton fields in St George have been treated for SLW. Last year more fields were treated earlier, and required a second treatment. It is clear that SLW is now… Read more »
