PHNOM PENH, June 21 (FN) — More than 20,000 hectares of farmland spread over 10 provinces in Cambodia have been affected by armyworms since last week, the Khmer Times reported on Tuesday, citing an agriculture official.

This includes thousands of hectares of rice along with other crops including cassava, peanuts and watermelons.

The affected farmland is mainly in the northern and northeastern part of the country, but the damage by armyworms is becoming such a problem that concerns are being raised about this year's rice crop - particularly as this sector has already been hit by a long drought.

Dy Sam An of the Agriculture Ministry's Crop Protection Department said about 17,000 hectares of land damaged by armyworms had been reclaimed thanks to intervention by agricultural ministry officers.

However, only 30 percent of this land has been rescued and brought back to productivity, he said.

"According to our studies, about 17,000 hectares of land has lost about 70 percent of its productivity," he was quoted by the newspaper as saying. "We can rescue only 30 percent of the total land."

Although the amount of cropland damaged by armyworms is still low compared with the total harvesting land nationwide, Sam An said it would still affect agricultural productivity if action is not taken to remove the worms.

He pointed to the weather as the possible cause of the infestation.

"The armyworms are basically present in the rice and crop fields," he said. "But the temperature this year was higher than normal, making good conditions for an increase of armyworms."