Following the success of CottonInfo researcher tours over recent years, the 2018 “Optimising Irrigation & Nitrogen” tour aimed to bring together researchers, industry, advisors and growers; with the objective of raising awareness of industry funded research programs, and promoting the latest best practice management.

Tour themes cover topical industry-wide issues, including management to optimise different irrigation systems, practices to maximise performance of irrigation systems, management practices to increase NUE, where N losses occur & impact of irrigation.

This project aimed to improve the profit of 3,000 cotton, dairy, rice and sugar irrigators with the support of 16 research and development partners and 19 farmer irrigation technology learning sites. Grower led irrigation research and extension aimed to collect commercially relevant comparative data on different irrigation systems and technologies. The intention was to provide growers improved understanding of the implications for capital investment, management and the resource requirements (water, energy and labour) associated with different irrigation systems and the adoption of automation technology and different approaches to farming systems.The project consistedof three components. 1.Practical, reliable irrigation scheduling technologies 2.Precise, low cost automated control systems for a range of irrigation systems3.A network of 19 farmer managed learning sites located around Australia.The project hadkey learning sites in Queensland; Ayr, Emerald, Warwick, Dalby, Toowoomba, St George. NSW; Moree, Narrabri, Wee Waa, Tamworth, Aberdeen, Whitton, Jerilderie. Victoria; Numurkah, Shepparton, Macalister. Goulburn Murray Irrigation District,Tasmania; Rocky Creek, Sisters Creek, South Riana, Montana, Cressy. South Australia; Allendale, Eight Mile Creek, Mt Schank. Western Australia; Harvey.The flagship strategy of the project was use of the key learning sites. These 19 sites were located all around Australia and were mostly on commercial farms. They all involved farmers, advisers, scientists and agribusiness. Thousands of people inspected or visited one of these sites. Some were more “research” focused; testing a hypothesis with robust scientific methods. Others were “demonstration” focused involving monitoring current actions and making changes as experience and confidence grew. One of the strengths of the project was having both approaches.Extension activities conducted by the project have resulted in the project being promoted to over 3000 irrigators and industry personnel at a range of field days, field walks and workshops.Severalactivities targeted sharing knowledge and collaborations across different sectors of rice, cotton, sugar and dairy. These included bus tours to other industries, social media, workshops and farm field days

In this investigation we have identified that approximately 30% of the sites in both years investigated are showing issues at depth with respects to root development and / or irrigation infiltration. There was broadly, two phenomena that have been identified in this study, those being; 1. Locations showing little or no root development during the period being investigated (crop year period) and/or 2. Locations showing depleted root development, or poor or nil irrigation recharge to the portion of the profile investigated during the crop year period. Further to our investigations it would seem that soil structure is being compromised and soil porosity lost either due to rain shifting salts down through the profile and causing a band of structural collapse, which links in to irrigation recharge issues, or is due to the increased frequency of irrigation causing increased dispersion and general structural decline of the soils in question, thus reducing root penetration, and moisture infiltration.

This study has identified spatially and temporally the extent to which these constraints to the production of cotton are an issue at an industry level. The findings of this study will allow the authors to focus future research efforts to investigate in more detail the causal factors behind the mechanisms identified. This research will also follow on to more detailed investigations as to how the mechanisms identified in this study are affecting plant root development and moisture infiltration again both spatially and temporally at field level .

* Testing various versions of SIRATAC on a commercial scale. * Ptoviding a database of the response of cotton to damage. *Comparing the response of the new varieties Siokra and DP90 with DP61.

This 3 year study examined the relationships between catches of Heliothis adults in monitoring traps and the abundance of eggs on cotton crops. In the first year paired traps of the two Heliothis species set up on the edge of cotton blocks showed a bias towards H. armigera in total catch compared with the proportion of the two species found in egg identification. The bias was greater with funnel than cone traps.

Since the first detection in the Dawson/Callide region of Central Queensland in 2012, reniform nematode has become a serious concern for cotton growers and researchers as well. Although reniform is considered one of the major diseases of cotton in the US, it is still considered a minor problem in the Australian cotton industry due to the limited scientific studies of the epidemiology of reniform in the Australian cotton cropping system. This project had a number of objectives to address knowledge gaps and obtain data to understand how the reniform nematode is interacting with cotton plants in Australian soil so that we can improve the management practice.

In this project, large numbers of cotton fields from both NSW and QLD have been monitored every season to confirm the presence or absence of plant-parasitic nematodes, and to provide an indication of possible nematode problems in the field. To understand the ecology of reniform nematode in Australian cotton, three glasshouse pot trials were conducted specifically to assess the vertical movement reniform nematodes in the vertisol soil, host/non-host suitability to different crops for reniform nematode, and effect of different reniform nematode population on growth and yield of different cotton varieties. The genetic diversity of the reniform populations found in different crops including cotton was compared to each other while it was also compared with international isolates. Additionally, three different field trials were conducted during this project period to investigate the effectiveness of seed treatment products (with nematicidal property) and a biological control agent to control the reniform nematode.

The seasonal field survey has provided information about the prevalence and spread of the reniform nematodes in Australian cotton fields. So far, reniform nematodes have been found in the cotton field in Central Queensland only. Early-season deep core samples (2018/2019 season) from different fields in Theodore shows the variable abundance of reniform nematode in the soil profile. In some fields, they were most abundant in the top 30 cm while some fields had a large population in the 30-70 cm below the surface. Interestingly, in some of the fields, the highest population was found at the depth of 70-100 cm below the soil surface. These results clearly show that the reniform can live and survive deep in the soil profile thereby providing a reservoir of nematodes that may reinfest the planting zone when cotton is sown. The vertical movement pot trial confirmed that the reniform nematode can move upward from deeper soil profile in the presence of a suitable host (cotton) once the seedling starts to grow.

The reniform population trial has provided some interesting results on the varietal response of cotton plants. Although all the varieties were treated similarly, reniform had a direct negative effect on growth (shoot biomass) and yield of variety ‘Sicot 714’ while ‘Sicot 746’ and ‘Sicot 748’ were not affected. This indicates the reniform nematode may significantly reduce the crop yield if the number of nematodes in the soil reaches a certain threshold and different cotton varieties may have different thresholds for reniform. The host/non-host trial has provided evidence that the rotation crops such as corn, forage sorghum, grain sorghum, and wheat are non-host of the reniform nematode. These crops were not infested by a reniform nematode, and interestingly, the reniform population in the soil of these crops was dropped to almost zero. Thus, crop rotation using any of these crops would be a good option to manage the reniform population in the field. It would be worthwhile to conduct a detailed field trial to evaluate whether similar results can be achieved in the field.

In the field trials, commercial seed treatment products with nematicidal properties had no effect on the reniform population in the soil. Similarly, another field trial with a biological product containing Bacillus species named FertiLink showed that this product has no effect on the nematode population in the soil.

The genetic diversity study has shown that the reniform nematodes found in different crops across Queensland are not different from each other. Although it is not clear if the nematodes on other crops are virulent to cotton, they may pose a great threat to the cotton field because of the cross-contamination of reniform nematodes from other crops to the cotton field. This study also confirmed that the Australian reniform population is not different than the international population, therefore the management practices from abroad can also be recommended in Australia.

The research results obtained during this project have been widely disseminated throughout the industry through presentations at different conferences and grower’s meetings.

The purpose of the 2016 Smarter Irrigation Technology Tour (an intensive three day tour to Northern Victoria and Southern NSW) had several objectives. To examine a range of surface irrigation layouts, the hydraulics, performance and suitability.To learn about automation technologies currently adopted in the irrigation industry, and see these technologies in action. To understand the application of automation equipment currently available, and how it could potentially benefit a farmers irrigation system. Improve participants understanding of various water management technologies (precision application, soil moisture sensors, EM survey). To showcase the irrigation research undertaken in the Smarter Irrigation for Profit Project and other CRDC funded irrigation research and provide a networking opportunity for irrigators, consultants and industry personnel from the rice, cotton, dairy and sugar industries.

The 'Tales from Cotton' Tour was designed as a cross-sector shared learning experience between the cotton and dairy industries on water and energy use efficiency. The event was an activity of the Smarter Irrigation for Profit- Tamworth Optimised Irrigation Dairy Farm Project. The tour was co-sponsored by the Australian Government Department of Agriculture and Water Resources as part of its Rural R&D for Profit programme, Dairy Australia, the Cotton Research and Development Corporation, Dairy NSW, and the Australian Government through Dairy Australia’s – Profitable Dairying in a Carbon Constrained Future Project. It was also supported locally by in kind support from North West Local land Services, Aquanorth irrigation, Hazell’s farm and Fertiliser Services, Davey and NSW DPI.

• Cotton aphid, two-spotted mite (TSM), banana or strawberry spider mite (SSM), cotton seedling thrips, western flower thrips (WFT) and green mirid were collected from Australian cotton growing regions.

• TSM regularly showed discriminating dose survivors against bifenthrin (Talstar®) and abamectin (Agrimec®) but seldom propargite (Comite®) or etoxazole (Paramite® or Zeal®) and never diafenthiuron (Pegasus® as CGA140408).

• Bifenthrin (Talstar®) and abamectin (Agrimec®) resistance detected in TSM was often at high frequency so may fail. The reason for this is not clear because pyrethroid use in cotton is limited and TSM do not fly so their immigration from sprayed crops other than cotton must be limited. It is speculated that the continuing increase in abamectin (Agrimec®) resistance is due to its use as a preventative treatment with mirid sprays. Mirid sprays are disruptive to beneficials so the inclusion of abamectin reduces the risk of subsequent mite flare.

• SSM was the most found mite species in Australian cotton confirming anecdotal observations that the cotton mite complex has changed and is no longer TSM dominant. Additionally TSM was restricted to NSW only and bean spider mite (BSM) was not collected so remains absent from Australian cotton.

• To allow resistance monitoring SSM baseline data was established for abamectin (Agrimec®), propargite (Comite®) and diafenthiuron (Pegasus® as CGA140408) and monitoring commenced but none was detected.

• A DNA based method to identify SSM, TSM and BSM was developed and successfully deployed by Biosecurity Australia where it has been used to identify more than 2000 quarantine mite intercepts.

• Cotton aphid was tested for pirimicarb (Pirimor®), OP-specific, pyrethroid, clothianidin (Shield®), diafenthiuron (Pegasus® as CGA140408), thiamethoxam (Actara or Cruiser®) and sulfoxaflor (Transform®) resistance. Interestingly pyrethroid resistance was often detected although it is not registered for this use in cotton and pirimicarb (Pirimor®) and OP-specific resistance was not detected so these chemicals can be used with confidence. Neonicotinoid survivors were detected in some strains but later thought vigour tolerant rather than resistant requiring discriminating dose adjustment to eliminate those false positives.

• Methods to transport and culture green mirid were developed making resistance detection possible with established laboratory based bioassay technology. Green mirid was screened for fipronil (Maestro® or Albatross®) resistance using a molecular-based diagnostic and none was detected.

• Neonicotinoid resistance was detected in cotton seedling thrips confirming anecdotal consultant / grower observations that seed treatments may not be working as well as they did. Unexpectedly WFT was the most abundant thrips found and worryingly spinetoram (Success® Neo)(the only registered control in cotton) resistance was detected in some strains.

• Much effort was put into transitioning resistance detection away from conventional bioassay to DNA based techniques. To this end indoxacarb resistance in cotton bollworm Helicoverpa armigera was extensively studied via genotype-by-sequencing and a diagnostic developed. Unexpectedly a second resistance mechanism was found preventing practical use of that diagnostic.

• A molecular diagnostic was successfully developed and deployed against TSM and etoxazole (Paramite® or Zeal®).

• Molecular methods to detect neonicotinoid in cotton seedling thrips and spinetoram (Success Neo®) in WFT were developed but require further validation.

Arbuscular mycorrhizal fungi (AMF) are important symbiotic partners to the majority of land plants. AMF depend on the plant community for photosynthate-derived energy. In return, AMF provide the plant with a range of nutritional benefits, increased protection against plant pathogen and environmental stresses. In natural ecosystems, AMF can significantly influence plant community structure and plant community stability. In cropping systems, AMF are important contributors to sustainable, low-input plant production. Excessive reduction in the diversity of AMF has occurred in some intensively managed soils as the result of intensive farming practices. Low taxonomic diversity in AMF communities may have important implications for ecosystem function. This thesis examined some of the whether AMF taxonomic diversity is reduced a cotton cropping system.

AMF were identified in the roots of mycorrhizal host plants and directly in field soil using PCR-based techniques. An AMF-targeted PCR primer was designed that enabled the specific amplification of AMF DNA in the presence of plant DNA and other non-target organism templates (Chapter 2). The primer was used to amplify AMF rDNA living in the roots of trap plants baited with field soil. The trap plants were grown in soil from long-term fallow, monoculture and rotation crops to examine whether rotation crops can influence the taxonomic diversity of AMF in cropped soils (Chapter 3). Trap plants harboured the same overall diversity of AMF in monoculture and rotation cropped field soils. The same taxa occurred in each of the fields. AMF in the cotton cropping vertisols appear to be robust. Spore dormancy may be common in many AMF (Chapter 5), and may account for the survival of the majority of AMF taxa in the long-term fallow soil.

TRFLP profiles were used to compare AMF communities in soil under different land management practices. DNA was extracted directly from soil to obtain community profiles. TRFLP analysis revealed that AMF are distributed more evenly in

cultivated than uncultivated soils. This finding has important implications for the design of sampling strategies for AMF community diversity studies.