In July 1994 the International Society of Soil Science held its 15th Congress in Acapulco, Mexico. Approximately 1800 ISSS members from almost 90 nations attended. The congress was held from Monday the 10th to Saturday 16th, the theme of this week was to discuss "Soil Utilisation in Harmony with Nature". Libby Roesner from the University of Sydney's Agricultural Chemistry and Soil Science Department attended this conference with funding from the CRDC to present a paper on the new methods she is researching for using image analysis techniques to evaluate soil structure in vertisols. Her paper was entitled: "Measuring the Impact of Intensively Irrigated Cotton Production in Australia - Using New Methods of hnage Analysis to detect degradation of Soil Structure" and was co-authored by Tony Koppi and Alex McBratney. A copy of the extended summary of this paper is included at the end of this report. Two papers in the symposia "Soil physics and environmental protection" were found to be particularly relevant to Libby's research. These papers both used computers to conduct quantitative analysis of soil structure, they looked at improving image analysis techniques to make them more practical to the end users. This report will take the form of full summaries and discussion of these two papers and then brief summaries of other papers relevant to Libby's work. Also a list of the titles of some other symposia from the conference that may be relevant to other cotton researchers are included

Modern molecular genetic techniques are used to examine Helicove1pa armigera for variation amongst individuals from different geographical locations around Australia. The prime objective has been to assess population structure: to find regionally diagnostic variation that will allow us, indirectly, to estimate the magnitude, direction and timing of movement patterns of these pest moths. This infonnation would be valuable to the ecologists in their efforts to better predict moth movement into cropping areas and hence improve control. It would also help in planning strategies to minimise the spread of insecticide resistance and thus benefit the Cotton Industry.

OBJECTIVES: 1. To study sampling and control practices for mirlds in irrigated and dryland cotton. * development of more accurate sampling techniques *insecticide trials to improve control *development of economic thresholds 2. To assess the importance of local alternate hosts in producing populations of green mirids that attack cotton. * assess mirid invasion of cotton from nearby lucerne and safflower *assess whether mirids invade cotton on weather fronts from distant sources

Supplementary funding was provided by the CRDC allowing three personnel ($1750 each, $5,250 total) from the pesticide chemistry group to attend the 8th International Congress on Pesticide Chemistry, held in Washington DC from July 4-9, 1994. Additional funding was provided by personal contributions (ca. 25%) and a University travel grant for postgraduate students. I.R. Kennedy also travelled to the Pasteur Institute in Paris, France in connection with a collaborative research program on nitrogen metabolism, with travel costs partly covered by an Austra1ian Research Council grant. Alice Lee, a CRDC Research Scholar working on the development of immunoassays for pesticides, also attended, funded separately.

Supplementary funding was provided by the CRDC allowing three personnel ($1750 each, $5,250 total) from the pesticide chemistry group to attend the 8th International Congress on Pesticide Chemistry, held in Washington DC from July 4-9, 1994. Additional funding was provided by personal contributions (ca. 25%) and a University travel grant for postgraduate students. I.R. Kennedy also travelled to the Pasteur Institute in Paris, France in connection with a collaborative research program on nitrogen metabolism, with travel costs partly covered by an Austra1ian Research Council grant. Alice Lee, a CRDC Research Scholar working on the development of immunoassays for pesticides, also attended, funded separately

Nutgrass control was examined in field and glasshouse studies. A nutgrass control strategy was developed based on Zoliar and in-crop Roundup, and infallow, cultivation in dry conditions and Roundup in wet conditions. Many unresolved aspects of nutgrass ecology and control remain. Future research should focus on developing weed management packages and identifying weaknesses and solutions for current and future weed management systems. Introduction In 1989 cotton growers identified nutgrass control as the area of highest research priority. Purple nutgrass ( Cyperus rotundus) is the weed species most seriously affecting cotton production, although another 7 Cyperus species occur in the cotton area. This project commenced in 1992 to continue the work on nutgrass ecology and control in cotton begun in project 60C

Supplementary funding was provided by the CRDC allowing three personnel ($1750 each, $5,250 total) from the pesticide chemistry group to attend the 8th International Congress on Pesticide Chemistry, held in Washington DC from July 4-9, 1994. Additional funding was provided by personal contributions (ca. 25%) and a University travel grant for postgraduate students. I.R. Kennedy also travelled to the Pasteur Institute in Paris, France in connection with a collaborative research program on nitrogen metabolism, with travel costs partly covered by an Austra1ian Research Council grant. Alice Lee, a CRDC Research Scholar working on the development of immunoassays for pesticides, also attended, funded separately

A large collection of microorganisms with over 2000 isolates has been established at the Australian Cotton Research Institute for the purpose of identifying potential bio-control agents and developing biological control methods for seedling diseases and Verticillium wilt. These isolates have been collected from within, on and around the roots of cotton plants collected from commercial crops in different cotton growing areas of New South Wales. The culture collection has been screened for in vitro antagonism against the pathogens that cause seedling diseases (Pythium sp., Rhizoctonia sp.), Verticillium wilt (Verticillium dahliae), black root rot (Thielaviopsis basicola), and bacterial stunt (Pseudomonas sp.) of cotton. About 29% of the culture collection inhibited the growth of one or more pathogens. A part of the culture collection was screened in in vivo glasshouse and growth chamber experiments for activity against the seedling disease pathogens and Verticillium dahliae. Several bacterial strains were found to be effective. Cotton seed inoculation with bacterial strains increased seedling survival by up to 80% (compared to the non-treated control). Some bacterial strains significantly reduced the incidence of Verticillium wilt. The proportion of plants with vascular symptoms ranged from 11-30% compared to 64-78% in the non-treated controls. Some bacterial strains which were effective in pot experiments significantly increased seedling survival in field experiments. The addition of nutrients to the inoculum and the use of combinations of bacterial strains as a means of enhancing biocontrol activity need to be investigated

The conference was held on the 23 - 27th of August, 1994 in Silsoe, UK. It reflected the broad spectrum where soil dynamics is applied, varying from the classic soil compaction studies, gantry systems, force predictions on tillage tools to ballistic penetration of stony soils. Researchers from the EEC, USA, , Canada, Japan, Israel and Australia were present. One oral paper, 'Stress paths under agricultural tyres' and one poster paper was presented, Controlled traffic, an Australian perspective'.

This report summarises the findings from the CRDC funded project "Managing soils to avoid compaction problems in cotton growing". The project ran from 1989/90 to 1991192. It had the principal aims of: * developing a management system for cotton growers that would minimize tillage requirements, and * avoiding current problems with soil compaction associat.ed with heavy machinery