Over the last quarter of a century, as problems in relying completely on pesticides for control of insects have become apparent, there has been renewed interest in the possibility of breeding cottons less susceptible to pests i.e. "host plant resistance". This paper describes some of the studies being undertaken at N.A.R.S. on this subject.

This handbook summarises the results of a four-year R&D project undertaken by staff at Victoria University and Monash University on the wetlands that fringe Lake Wellington in the Gippsland Lakes of south-eastern Victoria.

I will first mention some of the features distinguishing "Australian Conditions". Our industry has developed almost exclusively as a mechanised high-input industry with water and nitrogen being supplied liberally together with frequent insecticide applications to control insect pests. Thus it is similar to the American irrigated industry hut is dissimilar from less intensive forms of production practised in many less-developed countries. However it should also be realized that despite many similarities there are also important differences between Australian and U.S.A. growing conditions.

At Emerald, in the 1982/83 season, significant levels of field resistance in Heliothis armiger to synthetic pyrethroid insecticides were detected. In the field, many of the later maturing crops were severely damaged by insects despite heavy insecticide application. Research at Emerald and elsewhere has demonstrated the value of early maturity in avoiding late season insect damage in cotton.

The pink spotted bollworm (Pectinophora scutigera) has been an important.pest of cotton since 1924 in coastal, and sub-coastal Dawson-Callide regions of central Queensland. Its distribution has been described as.coastal Queensland, extending to the north coast of N.S.W., New Guinea, and other Pacific Islands. Despite its establishment in the Emerald Irrigation Area, where it was first recorded in 1980, it has not become an important pest there. It is not a pest of cotton in southern Queensland or N.S.W.

With increasing problems of resistance to chemical pesticides amongst cotton pests, especially Heliothis, more attention is being given to biological control agents, including pathogens. Pathogens are often more compatible with chemicals than predators and parasitoids, and many can be formulated and sprayed in the same manner as chemicals. In addition, some can be easily grown using mass fermentation techniques. They are usually completely harmless.to man, domestic animals and other biocontrol agents. However, much work remains to be done on the ecology and physiology of these pathogens, as well.as on the technical aspects of production, formulation and application.

Numerous studies on the effect of the nectariless gene on insect pests of cotton have been carried out both overseas and in Australia. However most of the latter studies have been conducted under small plot conditions which are not really suitable for assessing the effects of this character. This trial measured pest populations on large plots of normal and nectariless cotton isolines grown under standard commercial management practices. It was also designed to study anv possible differences in the ovipositional responses of the two Heliothis spp. (H._ armigera and H .punctigera) to these lines: an area of research which had been neglected in previous studies.

The adult stages of the two Heliothis species found most abundantly in the summer cropping areas of Australia (H. armigera and .H. punctigera) are easily distinguishable and have been so for some time. However the inability to distinguish the larval stages of these two species has hampered research on their ecology. For the past 5-10 years scientists studying.H. armigera and H, punctigera have found that in the early larval' stages Cuticle pigmentation separated the species. More recently hair colour differences on the last instar larvae have proved successful for identification. Verification and refinement of these techniques is presented