New technique targets pesticide-resistant insects

October 08, 2004

Australian and UK scientists have developed a technique to effectively control the 'super pests' that are highly resistant to pesticides used on important food and fibre crops worldwide.

The technique, patented by the NSW Department of Primary Industries and Rothamsted Research (UK), has proved effective against key insect pests that have evolved resistance to pesticides used in many agricultural industries, including horticulture and field crops.

Results of the research including details of scientific trials conducted in Australia, Spain and South Africa, are being presented today (Friday October 8) at the 2nd European Whitefly symposium in Croatia.

NSW DPI Principal Research Scientist, Dr Robin Gunning, said the technique was effective on insects that have developed a metabolic resistance to pesticides.

These include the cotton bollworm, cotton and silver leaf whitefly, and diamondback moth.

The invention relies on the use of enzyme inhibitors such as piperonyl butoxide (PBO), a natural substance derived from sesame oil.

Dr Gunning said previous efforts to use PBO failed, because the pesticide was inactivated by the insect's metabolic enzymes before the inhibitor had a chance to work.

Dr Gunning and her co-inventor, Dr Graham Moores from Rothamsted, designed the technology so that it incorporates a time delay mechanism.

Using novel micro-encapsulated formulations, they are able to deliver the enzyme inhibitor and the pesticide in a single dose. Firstly, an insect's resistance mechanisms are deactivated and then, four to five hours later, the insect is exposed to the pesticide.

Dr Gunning said the technology had been found to be effective in some of the world's resistance 'hot spots'.

"In NSW and Queensland (Australia), we conducted trials against the major pest of cotton, the cotton bollworm (Helicoverpa armigera) and silverleaf whitefly (Bemisia tabaci), and achieved virtually 100% mortality using pesticides that normally do not work."

"Similar results were obtained from trials in southern Spain with highly resistant white flies (Bemisia tabaci)."

Since resistance to pesticides first emerged in insect pests, more than 500 species of insects and mites have developed tolerance to chemicals 3 including pesticides regarded as being environmentally benign.

Dr Robin Gunning said the technology is likely to be of particular importance to the third world, where pesticide resistance and chemical overuse on crops is a major problem.

"It also has potential for public health programs such as malaria control."

An Italian company is working on a commercial release for a formulation designed on this technology which, in the first instance, will be available for use on cotton. It is expected subsequent formulations will be developed for other agricultural applications.

NSW Department of Primary Industries

Related Pesticides Articles from Brightsurf:

More plant diversity, less pesticides
Increasing plant diversity enhances the natural control of insect herbivory in grasslands.

In pursuit of alternative pesticides
Controlling crop pests is a key element of agriculture worldwide, but the environmental impact of insecticides is a growing concern.

Two pesticides approved for use in US harmful to bees
A previously banned insecticide, which was approved for agricultural use last year in the United States, is harmful for bees and other beneficial insects that are crucial for agriculture, and a second pesticide in widespread use also harms these insects.

Dingoes have gotten bigger over the last 80 years - and pesticides might be to blame
The average size of a dingo is increasing, but only in areas where poison-baits are used, a collaborative study led by UNSW Sydney shows.

Pesticides can protect crops from hydrophobic pollutants
Researchers have revealed that commercial pesticides can be applied to crops in the Cucurbitaceae family to decrease their accumulation of hydrophobic pollutants, thereby improving crop safety.

Honeybee lives shortened after exposure to two widely used pesticides
The lives of honeybees are shortened -- with evidence of physiological stress -- when they are exposed to the suggested application rates of two commercially available and widely used pesticides.

Pesticides increase the risk of schistosomiasis, a tropical disease
Schistosomiasis is a severe infectious disease caused by parasitic worms.

A proposal to change environmental risk assessment for pesticides
Despite regulatory frameworks designed to prevent environmental damage, pesticide use is still linked to declines in insects, birds and aquatic species, an outcome that raises questions about the efficacy of current regulatory procedures.

SDHI pesticides are toxic for human cells
French scientists led by a CNRS researcher have just revealed that eight succinate dehydrogenase inhibitor pesticide molecules do not just inhibit the SDH activity of fungi, but can also block that of earthworms, bees, and human cells in varying proportions.

Pesticides deliver a one-two punch to honey bees
A new paper in Environmental Toxicology and Chemistry reveals that adjuvants, chemicals commonly added to pesticides, amplify toxicity affecting mortality rates, flight intensity, colony intensity, and pupae development in honey bees.

Read More: Pesticides News and Pesticides Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to