Centre Pivot and Lateral Move (CF&LM) irrigation machines are gaining popularity within

the Australian cotton industry, as they can provide high application efficiency and

uniformity, low labour requirements, improved crop management flexibility, and fertigation

and chemigation potential. Growers and consultants who have not yet had experience with

these machines can be daunted by the choice and design considerations available whilst those

individuals using CP&LM machines often struggle with the increased level of management

required over their previous furrow irrigation operations.

This project has developed a number of extension, adoption and training tools to allow end

users to increase their understanding of CF&LM machines. These tools form a resource of

information that can be readily accessed as stand alone materials or delivered in a structured

manner.

The information resource developed consists of a number of articles and case studies to

provide opportunities for awareness raising and increasing adoption. In addition, a significant

training package has been developed that can be delivered to growers, consultants or

extension personnel to increase their understanding of the design and management

considerations and practicalities involved with CP&LM machines. Finally, chapters have

been contributed to the WaterPak manual and provide a readily accessible reference source

for information as required.

Much of this information has been developed including practical tips obtained from a series

of interviews of seven leading and innovative CP&LM users to incorporate the experience

that these practitioners have gained.

Fusarium wilt disease has the potential to cause significant yield losses and the removal of some areas from cotton production. It is therefore likely to impact on the long-term sustainability of the cotton industry. Conventional breeding techniques have made some progress towards generating resistance to Fusarium wilt in the cotton plant, but breeding efforts would be enhanced by knowledge of the factors that contribute to resistance. In addition, knowledge of the factors controlling the pathogenicity of the pathogen could provide the basis for the development of novel techniques that allow minimisation of the impact of the disease.

Resistance to the wilt pathogens is complex and probably controlled by many genes. This makes the task of breeding for resistance complex and difficult. In order to determine suitable approaches for improving cotton’s resistance by breeding or by the use of genetic engineering, we need an improved understanding of the existing plant responses that are effective at giving some resistance to Fusarium wilt. Identification of the genes deployed by cotton during infection by the Fusarium wilt pathogen, particularly those associated with the response of more resistant species or cultivars, could indicate new targets for effective breeding or for manipulation by genetic engineering. In this project, we aimed to develop tools for the large-scale study of gene expression in cotton and Fusarium, and to apply these tools to investigate gene expression in the host and the pathogen during the infection process.

During the course of this project, we developed effective microarray and model infection systems for the analysis of gene expression in Fusarium-infected cotton. This is a resource of potential use to the cotton industry in the identification of potential targets for generation of improved resistance to Fusarium wilt.

The most striking observation made during analysis of gene expression patterns was that in infected seedlings, gene expression changes in roots and hypocotyls appear to be different.

We found that repression of gene expression, particularly repression of genes for water-regulating proteins, such as aquaporins, was consistently observed in roots and hypocotyls. This repression appears to be associated with susceptibility. This identifies aquaporins as potentially important in the development of wilt symptoms.

In the Fusarium wilt pathogen, expression of a homologue of the AtsC gene from Agrobacterium may be important for pathogenicity, and expression of the retrotransposon foxy may provide a mechanism for rapid adaptation, and hence pathogenicity evolution, in Fusarium populations.

Fusarium wilt, caused by Fusarium oxysporum f. sp. vasinfectum (Fov), is a serious disease

of cotton in Australia responsible for substantial yield reductions. Since its detection on the

Darling Downs in 1993, Fov has spread to all major eastern cotton growing districts except

the lower Namoi. The significant crop losses that have already occurred and the increasing

incidence and severity of Fusarium wilt make Fusarium wilt the most significant challenge

to long term sustainable cotton production in Australia.

Improved farm management strategies can reduce yield losses and disease spread, but

developing resistant cultivars is by far the most effective long-term means of combating

fungal diseases of agricultural plants. Australian cotton breeders have significantly

improved the Fusarium wilt resistance of their cultivars, and new selections with even

greater resistance are nearing commercial release. Despite the admirable progress that has

been made, however, the current assessment is that new sources of Fusarium wilt resistance

are needed.

With the realization that the best the G. hirsutum gene pool has to offer may not be good

enough, We have looked to related Australian Gossypium species for novel sources of

Fusarium wilt resistance, identifying one possible source of Fusarium wilt resistance in G.

sturtianum. Although some of the G. sturtianum accessions tested are susceptible to fusarium

wilt, many of the accessions are more resistant to fusarium wilt than the industry standards,

and this resistance is expressed in the G. hirsutum background. Genetic analysis of G.

hirsutum x G. sturtianum hybrids, however, suggests transferring the G. sturtianum genes to

G. hirsutum will be difficult. Nonetheless, breeding lines are currently in the Fusarium field

nurseries and this selection process will continue.

The other important outcome of this project was the development of new experimental

populations and molecular markers that will, in ongoing research, provide a much better

understanding the genetic control of fusarium wilt resistance in cotton. Under this grant,

five chromosomes of the G. sturtianum genome have been identified as carrying genes that

may contribute fusarium wilt resistance. The experimental populations and molecular

markers will contribute to a more explicit genetic understanding of Fusarium wilt resistance

that will facilitate our ability to effectively transfer genes from G. sturtianum as well as other

novel resistance sources. With the apparent lack of immunity in the G. hirsutum gene pool,

these novel germplasm resources will become increasingly important to cotton breeders.

The development of IPM systems in cotton hinges on the availability of information on a wide range of issues. Included among these is the response of plants to pest damage, the impact of specific pests on yield and the effects of insecticides on pests and beneficials. Each of these factors has the potential; to influence when and with what a crop is sprayed with and hence to strongly influence the costs associated with insecticide use, the conservation of beneficial insects, resistance selection against pest species and environmental pollution. This research project has focussed on (1) plant responses to early season damage with emphasis on interactions with agronomic factors that may influence the degree to which plants compensate (2) the effect of aphids on cotton yield and initial studies of their ecology and (3) the effect of insecticides on target and non-target species, with particular emphasis on beneficial species so that growers and consultants have more information on which to base insecticide choice decisions.

This project has led to a significant advance in our understanding of the feeding behaviour of the adult heliothis moth. It has used detailed studies in ecology and behaviour of H. armigera to examine novel control strategies based around luring and killing adult moths. Our results will assist the design of more effective lures through consideration of important behavioural effects and odour preferences. We designed and executed a series of detailed experiments using odour lures and extended these experiments to allow moths to forage freely on flowers; testing their preferences for odours. Our results demonstrated odour learning on a number of levels, and provided evidence that flower visiting history influences attraction to odours. In addition to this we discovered that the enantiomeric forms of odour compounds may differ in their attractiveness to adult female moths, a finding that may improve the selection of synthetic odours for lures. Our results have been submitted as 3 key papers to international scientific journals.

We show that the location of feeding sites for adult moths influences the distribution of heliothis eggs. Our results imply that adult feeding sites have the potential to draw in adult moths to feed and that moths may then lay on nearby cotton plants. In addition, we show that male and female adult H. armigera moths may have differences in nectar feeding preferences. Our findings help elucidate why certain crops may be more attractive than others and why certain stages of the plant life cycle receive more heliothis eggs than others.

We have collected data on nectar foraging moths, which suggests that virgin female and male moths may be flying specifically to certain crops to feed. Specifically, we have shown that pigeonpea (Cajanus cajan), used as a refuge and trap crop, is highly attractive as a host for feeding adult moths. We have backed field studies with controlled experiments carried out in outdoor flight cages. Our findings could be utilised to improve control methods and also cautions the use of some crops as refuges and trap crops, in that they may extend the lifespan and fecundity of this pest species.

In conclusion this work has contributed to the design of new heliothis control strategies, providing information that will help the improvement of lure and kill, trap cropping, refuge cropping and population monitoring strategies and the future production of new varieties of cotton with lower attractiveness to moths. It will benefit the Australian cotton industry and the Australian community by aiding the design and development of new economic and environmentally friendly methods of insect pest control.

INGARD® Cotton varieties express Bt toxin in all plant parts except for the flowers. Because Helicoverpa moths frequently target flower buds and flowers as oviposition sites, a proportion of their neonate larvae may establish themselves on or in the flowers in a Bt-free location on the cotton plant. This may allow them to develop to a size at which they are more tolerant of Bt toxin on other plant parts. Such larvae may subsequently be capable of damaging fruiting structures and other plant parts before they are affected by the Bt toxin.

Honey bees are known to visit cotton flowers, and this project set out to determine whether they may provide an efficient means of depositing HNPV (Heliothis nuclear polyhedrosis virus) propagules directly into cotton flowers, and thereby help to eliminate an otherwise safe haven on INGARD® plants. Honey bee hives can be readily modified to disseminate virus or other microbial biocontrol agents, and the hives are easily transported to required areas. Honey bees from such hives have been shown to successfully act as vectors of HNPV against Helicoverpa zea on Crimson Clover Flowers (Gross et al. 1994), and as vectors of Bt for control of Banded Sunflower Moth on Sunflowers (Jyoti and Brewer 1999). Results from both these studies were impressive. For example mortality of H.zea larvae, when fed crimson clover flowers that had been visited by bees, increased from 12% in Control fields to over 80% in fields treated with HNPV (Gross et al. 1994).

The project initially aimed at assessing the potential of Eretmocerus mundus (APF) as a control agent for silverleaf whitefly (SLW). As the crops where SLW is a pest are annual, mechanisms of achieving early colonisation need to be assessed. Further, a broad range of pesticides are used in these crops and their potential impacts on the parasitoid are unknown. The capacity of E. mundus to control field infestations is also untested.

After the second year it was apparent that while E. mundus performed well under controlled conditions it lacked the ability to exert sufficient control on outbreaking populations. A decision was made to then to better understand the interaction between the native Bemisia tabaci and the exotic B biotype. The background to this shift was the observations that in the cotton growing areas of QLD SLW was patchily distributed and rarely found on cotton. In NSW, surveys of cotton in 1995 and 1996 found small numbers of SLW. Since then 100 leaves have been collected from more than 190 crops with no SLW being recovered. By way of contrast, in both NSW and QLD, the Eastern Australian Native (EAN) biotype of B. tabaci occurs commonly in cotton, although at densities of less than 3 individuals per leaf. The most common whitefly species in cotton remains the greenhouse whitefly (Trialeurodes vapororarium). The reasons for the low numbers of SLW was unclear but there were several possibilities. The most likely of these was an interaction between the two biotypes of Bemisia tabaci, climatic suitability and host availability.

Resistance is an ongoing concern with the management of H.armigera in the Australian

cotton industry. Management strategies are in place to either prevent, or retard, further

development of resistance to either chemical insecticides or to the Cry1Ac protein in

transgenic plants. However, these strategies, particularly those concerning the Cry proteins, are based on models of resistance, as information is lacking regarding putative resistance genes in H. armigera. This project aimed to increase our understanding of the genetic basis of resistance ideas, about which underlie the basis of the resistance management strategies.

The focus was on Bt resistance, but the work is also directly applicable to conventional

chemistry insecticide resistance.This project was a collaborative one between the CSIRO genetics group in Canberra and Dr Heckel's group at the University of Melbourne. It made use of recent advances in genetic studies of H. armigera, in particular, the development of a genetic linkage map by Dr Heckel

for this species, developed through the use of AFLPs. Linkage maps enable a speedier means to define the genetic basis of resistance than is available through more conventional approaches.

The role of a Trainee Industry Development Officer working with grower groups in the Border Rivers region, has given a good understanding of cotton industry issues and grower practices. The formal training in the Cotton Production course and the other extension courses has given me a good technical background in production and extension. By participating in various industry updates and conferences I was able to gain understanding of the current research and problems within the cotton industry. Maintaining a network of contacts within the cotton industry allows me to keep up to date on issues within the industry as well as a broad source of information to call upon.

Training in all aspects of cotton production with particular attention given to the following disciplines.

• Integrated pest management

• Plant physiology and nutrition

• Soil and irrigation management

• Establishing effective growers groups and networks.

Helicoverpa spp. are arguably Australia’s most important insect pests, costing the

economy $200-300M annually. Significant advances in the management of

helicoverpa have been made since the last workshop in 1995.

A two day workshop at Toowoomba on 21-22 June 2004 provided an opportunity for

around 50 participants with interest in helicoverpa R,D&E from State Agriculture

Departments, CSIRO, Universities, R&D Corporations, consultants and industry to

discuss issues related to the management of these pests in grains, cotton and

horticulture. The first day involved a series of short review presentations to set the

scene, followed by questions and discussion from the floor. The second day

involved workshopping sessions to tease out priority issues, identify gaps and

provide direction for future research.

The objectives of the workshop were to:

(a) review the developments in R,D&E related to helicoverpa management in

Australia since the last workshop;

(b) review the role of extension in the development and implementation of Area-

Wide Management (AWM) programs by growers in north-east Australia;

(c) examine the prospects for successful AWM, and

(d) provide direction for future R,D&E requirements for these pests.

Whilst the focus of the workshop R,D&E concerned with advancing knowledge and

management capacity of Helicoverpa spp., there was some discussion about the

benefits that could accrue to industries or regions, or in managing other pest

species, from extending techniques used successfully with helicoverpa.