Diamondback moth caterpillars are major and ubiquitous pests in over 80 countries, causing losses of 30 to 90% of cabbage and cauliflower production annually in the developing world at a global cost of over 1 billion US dollars per year and still rising (Talekar and Shelton, 1993). Cabbage is a key cash crop for large numbers of smallholder farmers in Asia and Africa as well as a primary vitamin and dietary fibre source for the urban and rural poor in the developing world. Diamondback moth very significantly restricts availability of vegetable brassicas, increases prices and introduces significant health hazards through farmer contamination with insecticide and consumed pesticide residues. Studies undertaken for CIMBAA in India (Sandur 2004), Indonesia (Rauf et al 2004) and independent studies in Kenya (Oruko and Ndungu 2001) have confirmed the importance and apparent intractability of caterpillar pests of cabbage and cauliflower.

Diamondback moth has developed resistance to almost all insecticides in many parts of the world. Conventional crop breeding programs have failed to develop varieties with really useful resistance to diamondback moth. Alternative pest management solutions based on agronomic regimes, biological control or chemical pesticides have proven effective in some area, especially in the highlands, but insufficient in lowland areas and cumbersome to implement successfully, especially by poorer farmers in developing countries.

A collaborative initiative between development oriented, science-based, public partners and an international vegetable seed company is developing a project which aims to break the circle of insecticide use and insecticide resistance of the Diamondback moth, while also giving control of other caterpillar pests. The partnership focuses on sharing benefits for the farmer, the consumer, the environment and the company, developing cabbage and cauliflower varieties with consistent protection from key caterpillar pests, using insecticidal proteins produced from two different soil bacterial (Bt) genes. The caterpillars have not been widely exposed to these two proteins before and background research has shown that they cannot readily develop resistance to both toxins simultaneously. Closely linking the two Bt genes before inserting them into the plants should prevent accidental separation by breeders which could lead to produce single Bt gene plants. The insect-resistant plants will be introduced within a full Integrated Pest Management programme (including the promotion of the use of natural enemies of the pests, and cultural, as well as technology-based practices), maximizing their profitability, effectiveness and long-term sustainability. As a result, the production costs for these crops in the concerned countries and food security would be significantly improved. We expect that this will assist in reducing poverty and will remove a significant public health burden from excessive sprayed insecticides.