Protect livelihoods and food security by preventing the entry and spread of new pests of plants into a country.

It now represents 92 percent of California's crop - a virtual monoculture that leads to fears that a new pest or disease could devastate the industry.

Everywhere, scientists were coolly endeavoring to combat the new pests and were seeking to devise more efficacious weapons for use against the outsiders.

Much of the genetic variation used in evading the damage caused by new pests is still derived from resistant wild stock.

Once a new pest or disease makes a landing, the consequences can be dire, and expensive.

While there is hope for a chestnut revival, a new pest, the chestnut gall, has appeared in Georgia.

They sought strains which could protect crops from the new pests.

Tight border controls to improve biosecurity have been put into place to ensure any new and unwanted pests and diseases do not enter the country.

But for Malaysia's own security, it seems risky to convert so much into a monoculture that could succumb to a new pest or disease.

Climate change has altered the conditions in which farming takes place: new pests are appearing, and natural disasters decimate harvests.