Plant diseases

From VOA Learning English,

this is the Agriculture Report.

Insects and diseases that attack food crops

are moving as risen temperatures

bring changes to the environment.

Plant diseases alone destroy an estimated

10 to 16 percent of the world's crops in the field,

experts say, plant diseases destroy

another 6 to 12 percent after harvest.

A new study examines the movement of crop pests and diseases,

and how it will effect agricultural production worldwide.

Dan Bebber is a senior research fellow

at the University of Exeter in Britain.

He says research has shown

that wild plants and animals are moving

toward Earth's North and South poles as the planet warms.

Mr Bebber wanted to know if the samething was happening

with organisms that attack agricultural crops.

He examined reports of first sightings of new insects

and diseases around the world.

The records came from CABI

- the Centre for Agricultural Bioscience International.

He says the group began collecting information

from developing and industrialized countries years ago.

Dan Bebber and his research team studied 612 different organisms

- from viruses and bacteria to insects like beetles and butterflies.

They found that since 1960, crop pests and diseases

have been moving toward the poles

at an average rate of about 3 kilometers each year.

Mr Bebber says this puts

the most productive farmland in the world in danger.

"As new species of pests and diseases evolve

and potentially the environment for them

becomes more amenable at higher latitudes,

the pressure on the breadbaskets of the world is going to increase."

Farmers face other threats.

Invasive species passed through trade are also causing problems.

Gene Kritsky is an Entomologist

at the College of Mount St. Joseph in Ohio.

He specialises in the study of insects.

He says climate change may improve conditions for some invasive species.

"It means that species in other parts of the world

that might do well in warmer temperatures

can now do well in the breadbasket of America."

Another Entomologist Christian Krupke of Purdue University says

the effects of these changes will depend very much on the crop,

the insect and the disease.

But he says the research is a warning sign

that people should care about climate change

and do something about it.

And that's the Agriculture Report from VOA Learning English.