Bioinsecticide for combating a pest that affects the tomato and the green bean

The tomato fruitworm is the name given to an insect pest which, due to its polyphagous character, causes very serious damage to a number of plants, such as the tomato and the green bean. Its danger is greater if one takes into account the fact that this pest has developed resistances to chemical insecticides, including tot he latest ones. Thus, a Crop Protection research team from the Public University of Navarra have started work on developing a bioinsecticide that can be used as an alternative control measure.

The research project is called “Characterisation of isolated multiple Helicoverpa armigera nucleopolyhedrovirus for its development as an active material in bioinsecticides”.

A worldwide pest

The Helicoverpa armigera insect, the scientific name for the tomato fruitworm, is found widely distributed throughout Europe, the Middle East, Africa and Oceania, where it is considered to be a very serious pest. In Spain it has been traditionally one of the most important pests in cotton and maize but, since more than a decade ago, it has become a feared pest for several vegetable crops. These insects have a predilection for fruit, penetrating into their interior, on which they feed and frequently emigrating from one fruit to another and capable of destroying several during its larval stage.

Control of this pest with synthetic organic insecticides, apart from the toxicity and environmental problems arising from their use, is turning out to be of little efficacy due to the great capacity the organism has for developing resistances to a great variety of active materials.

Thus the need to put into place alternative control measures, outstanding amongst which is the biological control with baculovirus, a virus exclusive to insect pathogens, and which show a great number of properties favourable to being developed as bioinsecticides.

Contrasted experience

There currently exist some 40 products available in different countries for different species of lepidoptera pests, the active material being baculovirus. Amongst these are some that are specially developed for the control of H. armigera in cotton, but there are still no products specific for vegetable crops.

This is precisely the aim of the mentioned research group from the Public University of Navarra: to design a bioinsecticide that can be used as a control measure. In concrete, as a first stage – that corresponding to the research team -, the biochemical and biological characterisation of the most specific strains of H. armigera found in the extensive collection of baculovirus available to the team will be undertaken. Then, those strains showing the best biological characteristics for their future development as bioinsecticides will be selected.

This first stage is to last two years – to the end of next year, 2006, approximately -, and the completed development of the bioinsecticide could take another two years.

It should be pointed out that the Crop Protection research team from the Public University of Navarra have undertaken, over its 11 years of research, important work on the development of baculovirus as bioinsecticides.The team is currently working together with a company to design a highly effective product against the larvae of Spodoptera exigua, another lepidoptero important in market gardening.