We determined the efficacy of direct applications of a range of concentrations between 1% and 10% of an nC24 petroleum spray oil (PSO) (Sacoa, Biopest) for use against the cotton aphid, Aphis gossypii. We focused on the effects of the oils on aphid behaviour and mortality. We also determined the indirect effects of the deposits of the PSO. We focused on the effects of the oils on acceptance of cotton as host plant by the aphids, as well as on aphid mortality rates and their success in establishing colonies.

Cotton aphid, Aphis. gossypii is a major pest of Australian cotton due to an ability to develop resistance to the carbamate insecticide Pirimor and organophosphates generally. To test the pirimicarb and organophosphate resistance status of Australian strains of cotton aphid, the PCR method of Andrews et al (2004) was adapted by us to a real time PCR assay and restriction enzyme digest. The method was tested against 5 reference strains in which the resistance profile was known, 3 of which were used to test a double digest (both SspI and PdiI). In addition, 24 field isolates were assayed using bioassay and real time PCR. Both methods confirmed Pirimor resistance in a single isolate and showed the remaining isolates tested via both methods to be susceptible. Real time PCR has potential to replace bioassay for the routine resistance monitoring of Pirimor in cotton aphid.

Presentation slides

Our work focused on selecting a 'baseline' set of socio-economic indicators that could be used to track the economic and social condition of cotton communities over the life of the CRC and beyond. These could have a variety of uses, including:* helping the industry to monitor and understand its influence on its communities; * helping communities monitor and understand their influence on the industry; and *helping both industry and community manage their changes and interactions

An industrial shed (9 x 12m) with concrete flooring and roller door access was constructed at ACRI in November 1998. The shed was sited in close proximity to other sample processing buildings. A drying room was constructed within the shed using insulation panelling with single door access. This room was then fitted with shelving and a mobile dehumidification unit installed. This unit efficiently removes water vapour from the atmosphere within the room using refrigeration technology. The writ can remove in excess of 40 L of condensed water vapour- each day. This is sufficient to dry plant material on fully laden shelves within 2-3 days. The drying period is similar to the existing dehydrators, but the new facility uses a fraction of the electricity consumed by the older dehydrators. The unit operates at about 50 Degrees C compared with the older units which operate at 80 degreesC. Thee unit was operating by mid-January 1999, prior to the busiest part of the cotton season. It was in constant use until mid-winter 1999.

Presentation on irrigation and soil oxygen

Presentation on the Boyce Cotton comparative analysis

For season 2004-2005, sixty-one percent of cotton aphid populations were Pirimor resistant but Intruder, Actara, Thiodan and Pegasus susceptible. Two-spotted mite was Agrimec, Comite and Pegasus susceptible. Intrepid resistance was detected in 43 and Talstar 57 percent of mite stains. Curacron resistance in two-spotted mite was ubiquitous and often at high frequencies. At the time of writing testing for season 2005-2006 was incomplete but Pirimor resistance seemed less than in season 2004-2005. Intrepid resistance was still detected in 67% of the two-spotted mite strains although the product was not available for use in cotton. We conclude that the resistance management strategy for cotton aphid and two-spotted mite should remain 'as is' for season 2006-2007.

The detrimental effect of aphid feeding on plant growth has been reported from various crops around the world (Atakan and Ozgur, 1996; Hille Ris Lambert, 1970; Kimmins, 1986; Lowe, 1967; Miles, 1987). We first studied the effects of aphid feeding on cotton and dry matter production in 1999/2000. Prolonged feeding by heavy aphid populations significantly decreased cotton and dry matter production and raised questions about how aphids caused these effects. Contamination of leaves by honeydew, salivary effects and assimilate removal could all be factors. We also noticed that aphid infested plants often grew poorly, even before the level of honeydew production was very high, and speculated that perhaps aphids also affected the photosynthetic rate of cotton. Since it is known that the removal of leaf sugars (such as occurs during aphid feeding) can increase the concentration of sugars in the leaf and thereby give negative feedback to photosynthesis (Blechschmidt-Schneider, et al., 1989; Franck, et al., 2006), we decided to consider this factor first. Our subsequent work investigated any relationships between aphid populations and plant photosynthetic response; how many aphids would be required to elicit a response; and the duration of the response to become measurable.

Key points *Cotton aphid uses a wide range of hosts in winter when cotton is not available. * Farm gardens provide a habitat for cotton aphid especially when conditions are dry. Aphids sampled from such sites show resistance to traditional chemical controls. * Aphids maintain chemical resistance within populations by reproduction by cloning. * Reducing the abundance of aphid hosts on farm through winter, especially weeds, may help reduce abundance on cotton. A list of key hosts is provided.