Imphal (PTI): Harmful short-horn grasshoppers have swarmed paddy fields in parts of valley districts of Manipur, causing concern among farmers as the harvesting season draws nearer.

Official reports on Monday said the insects attacked paddy plants at Khangabok in Thoubal district and Kiyamgei in Imphal East district.

A team of experts from state agriculture departments and scientists from the Central Agricultural University (CAU) had visited the areas yesterday, official sources said.

Senior assistant professor of CAU (entomology department) Kh Ibohal said the team had found that majority of the insects were of the short-horn variety, which can destroy standing crops.

He said grasshoppers were of three types -- small grasshoppers (brown and ash in colour), rice grasshopper (grey and green) and surface grasshoppers (green with long wings). The most dangerous of these is the rice grasshopper.

He attributed the sudden rise in the population of the insects to the untimely heavy rains in January, this year which created a favourable condition for hatching eggs on a mass scale.

Ibohal said a joint effort of farmers and officials was needed to control the pest as farmers alone cannot protect their crops from the attack.

Official sources said experts had investigated a variety of grasshoppers swarming the hill district of Tamenglong bordering Nagaland last month, but the type was harmless long-horn grasshoppers.