Greg Parle and René van der Sluijs travelled to Bremen in April 2008 primarily to attend and present a paper

at the 29th International Cotton Conference in April 2008, .

Salinisation as a consequence of irrigation can occur as a result of the application of poor quality (i.e. saline) water or mobilisation of salts from rising water tables (i.e. caused by excessive groundwater recharge). In order to determine the threat of salinisation a project entitled “Understanding the salinity threat in irrigated cotton growing areas of Australia” was established in 1991. Phase I (Preliminary Studies) involved testing existing field techniques (i.e. electromagnetic induction – EM) to assess cause and management of subsoil salinity at the field level, in the lower Namoi valley. Phase II (Methods and Techniques) was aimed at extending these techniques by i) automating EM instruments such as the EM38 and EM31 onto a Mobile Electromagnetic Sensing System (MESS), ii) developing district scale EM investigations (i.e. EM38 and EM34) and iii) carrying out regional scale modeling, in the lower Namoi and Gwydir valleys.

Phase III (Implementation and Management-CRC11C) was aimed at implementing the field (i.e. MESS), district (i.e. EM38 and EM34 surveys) and regional (i.e. reconnaissance soil surveys) methodology developed in Phase II, in each of the major cotton-growing areas of central (eg. Macquarie valley) and northern (eg. Gwydir valley) NSW and southeast (eg. Macintyre valley) Queensland. This was achieved by:

a) initial consultation with various community groups (eg. Bourke Irrigators Association) to ensure research projects developed were consistent with natural research management issues in each cotton-growing area;

b) generate matching research funds through the Natural Heritage Trust and Salt Action Programs;

c) collection of EM34/38 data and soil information in the root- (0-2 m) and vadose- zones (2-12 m) to measure, model, map, manage and monitor soil salinisation processes.

The main outcomes of the research carried out are the collection of over 7,500 EM34 and EM38 measurements and 350 soil profiles (0-12 m sampled at 1 m intervals) in the seven cotton-growing districts across five valleys. As shown in this report the data collected has been used at the district level to map a) deep drainage risk areas, and b) spatial distribution of subsurface saline material, whilst on the field level the cause and management of a) soil salinisation and b) water logging.

In order to consolidate the data collected in Phase III, for improved natural resource management, a follow up project is required (i.e. Phase IV-Interpretation and Extension). The main aim of Phase IV is to interpret the information collected and develop new methods (i.e. groundwater modeling from piezometric data) for understanding how point source soil salinisation occurs in irrigated cotton-growing areas. From the information collected and modelled it is expected that best management options can be devised for improved natural resource management. This is particularly the case in the Bourke, Warren and Trangie districts, where irrigation salinisation is problematic. In addition, detailed EM surveys are required to understand at the field level what the appropriate management options are required for improved natural resource management.

Over the past 10 years the rapid uptake of IPM and transgenic cotton has allowed a dramatic reduction in the use of insecticides in cotton. However, new technologies bring new challenges, and amongst these for Bollgard II® cotton and IPM systems is the emergence of pests that were previously controlled by insecticides applied against other pests. A further challenge is the potential for high retention in Bollgard II® crops which may affect compensatory capacity and potentially limit yield through premature cut-out. This project has addressed four broad areas of relevance in the Bollgard II® era.

1) The effect of aphids on cotton photosynthesis and yield.

Our research has shown clearly that aphids can reduce the photosynthetic rate of cotton, resulting in reduced yield and development. A statistical relationship predicting yield loss from aphid densities has been developed and used to produce look-up charts to estimate potential yield losses from this pest. This relationship will be used to enhance the CottonLOGIC decision support tool.

2) Effect of insecticides and miticides on predators and parasites.

A table summarising the effects of all currently available insecticides and miticides on beneficial predators and parasites was developed and updated regularly with data from this project, as well as that from collaborators. This table (IPM Supporting Document 1 ‘Impact of insecticides and miticides on predators in cotton’) has been widely distributed and used throughout the industry and served as a template for other crops.

3) Effect of early damage on Bollgard II® and UNR cotton.

We found that cotton can recover from damage by thrips through a process known as ‘accelerated ontogeny’. This is when the plant ceased development of damage leaves early in order to speed up the development of new, undamaged leaves to recover leaf area. This information will be used to update thrips compensation routines under development in the OZCOT cotton simulation model. A range of experiments were co-ordinated with the Cotton Extension Team. Outcomes from experiments were (i) Bollgard II® cotton varieties can compensate as well as or better than conventional varieties (ii) cotton with early retention levels of 80-85% showed no indication of premature cut-out and treatments to manipulate plant growth to avoid this problem did not increase yield but did cause delay iii) UNR cotton is less able to compensate for early damage than cotton on conventional 1 m beds (iv) in conventional cotton in a cool region (Hillston) later tip damage, at nodes 6 or 8, carries a higher risk of delayed maturity. Outcomes of this research have been extended to industry and have also increased IDO and crop manager’s knowledge of cotton compensation and provided valuable additional research data

4) Emerging pests and late season damage.

We found that late season damage to younger leaves (i.e. removal of the top 25 cm or top 6 main stem leaves) may have a greater effect on yield than expected. This raises questions about l for leaf damaging as opposed to fruit damaging pests and should be investigated further. We also investigated the effect of jassids on cotton yield and found a initial experiment showed a negative linear relationship between jassid density and yield. This should be investigated further.

Host Plant resistance is one such method and has been adopted in developing plant resistance to a range of plant problems. Plants posses both natural physiological and chemical defence mechanisms. If the Plant breeder, through a resistance measuring technique, could select for these traits, he could then develop Plant varieties with high levels of resistance factors

The frequency of resistance to synthetic pyrethroids in Heliothis armigera has been monitored in the Namoi Valley since the introduction of the insecticide resistance management strategy in 1983. During this time the frequency has varied cyclically. Although the magnitude of the changes varies from year to year, the same pattern is evident each cropping season: the frequency increases in stage 2 (the six week period during which pyrethroids are used), continues to increase in stage 3 (autumn) and then falls by stage 1 (spring and early summer) of the following cropping season (Forrester and Cahill 1987).

All insecticide management decisions require a solid platform of reliable data and this can only be achieved by a long term committment to pesticide studies, obtaining baseline susceptibility data and monitoring of changes in resistance levels. In this paper, a summary of findings from this resistance monitoring program from 1974 to 1988 will be presented. Insecticides screened have been pyrethoids, endosulfan, carbamates and organophosphorous compounds. At the same time, research has been conducted to develop innovative bioassay methods for chemicals with novel modes of action or unusual methods of entry into Heliot:h.is spp.

At the time of the initiation of the H.armigera resistance management strategy, there was a need to demonstrate that any increase in resistance was limited to crops sprayed with pyrethroids. An increase in resistance in these populations could lead to a consistently high level of resistance in cotton areas. This paper reports the results of a resistance survey on H.armigera collected from 1983-1988 in New South Wales.

Insecticides can poison insects in many ways. Insecticides r...:an interfere with metabolic processes , of energy production, cuticular growth and hormone production. Many i nsecticides, being potent onerve P>isons, can stop nervous transmission through the insect nervous system. Resistance is now apparent to most. , if not all, types of insecticides and research on the mechanisms of resistance has always been part of the mult disciplinary approach which should be adopted for All cases of insecticide resistance management.. To deal with pyrethroid resistant H. armigera it is necessary to know exactly why the insects are resistant.

Most, if not all, entomologists involved in the development of cotton insect management systems agree that an essent1al part of a successful Integrated Pest Management (IPM) program is the ava;lability of an eff1cac1ous material against a system's key pests. Certainly an app ropriate quest1on 1s this: What are th.e prospects for maintaining such compounds1 First, a little history: During the past three decades the resistance phenomenon has removed from our insecticide arsenal three classes of chem1cals for at least one key pest in the major crops system. This is a loss of an efficacious materials at an alarmi ng rate of one class of chemicals for each decade. It presently appears that the more recent group, the synthet1c pyrethroids, are facing the same demise.

As most of you are aware, the Siratac Cotton Management Advisor computer program is being rewritten. There will be those amongst you who are unaware as to why this is being done. The main reason for all this effort is that the existing Siratac is running out of puff. The constant demand for changes in Siratac to reflect changes in the industry is causing Siratac to strain at the edges. In addition, looking not to far into the future, one can see requirements that are not easily provided by Siratac, including a modern intelligent interfaces, improved graphics, flexible access to grower data, ad hoc reporting etc.