One such form is biological control, which relies on the use of natural pathogens and parasites to control the pest species. A group of pathogens that have been used for the biological control of several insect pests are the nuclear polyhedrosis viruses (NPVs). Five features of NPVs give them great potential for use as biological control agents

BACILLUS THURINGIENSIS use as an insecticide for 25 years despite formidable competition from conventional insecticides is largely due to its safety and compatibility. mainly with natural control but also with chemical insecticides. For example. a chemical ovicide is frequently used in conjunction with Bt for early-season Heliothis control. This combination is particularly useful in districts where a mite problem. could be induced by the use of a broad spectrum. insecticide which would destroy the natural mite predators. In Thailand,. its use against cabbage moth larvae is essential because of resistance to all alternative insecticides.

The study reported here concentrated. On these sap-suokinq bugs, which were reputed to damage seedling and early-squaring cotton

Biological control represents one alternative to insecticides. The Cotton Research Council (CRC) has funded a project to study native egg parasites of Heliothis. This work is part of a program aimed at using egg parasites to control Heliothis on cotton

My objective has been to construct life tables describing Heliothis egg and larval survival on the major crops of the Darling Downs over several seasons.

One of the important characteristics elevating Heliothis spp. to major pest status is the ability to enter facultative diapause. Diapause maintains populations during periods when hosts are unavailable or conditions are not conducive to reproduction and population survival. Development resumes in spring with the onset of warmer temperatures and moth emergence becomes concentrated. Survival of overwintering populations and the contribution of this carry over of moths to the development of populations the following season are not well established in Australia. Overwinter survival studies for H. punctigera and H. armigera were conducted in south-east Queensland to investigate differences between the two species.

Although resistance to insecticides was a well-documented phenomenon, pest control operators have merely switched from less effective insecticides to newer more potent compounds and thereby kept ahead of the resistance problem. Moreover, the constant development of resistance continually created new markets for alternative insecticides, and planners merely took this into consideration in forecasting trends. This practice of planned obsolescence was only possible with a steady supply of new insecticides, a supply that no longer exists

No final report

This paper outlines the requirements to effectively operate a Controlled Traffic farming system, with emphasis on the need for some form of automatic steering assistance for farm machinery. The material presented is based on work being widertaken. at the U.S.Q. for the Cotton Research and Development Corporation. Project DDI 1 Lis developing guidelines for establishing controlled traffic farming systems. Project goals include the provision of a bolt-on, economical, reliable automatic guidance system for existing farm machinery.