The worst affected upazilas are Netrakona Sadar, Kendua, Atpara, Barhatta and Purbadhala.

Pests are eating up seedlings of transplanted Amon on thousands of hectares.

According to Agriculture Extension Department (AED) sources, about 1,28,640 hectares of land were brought under Amon cultivation in the district with a production target of 2,52,947 metric tons of paddy this season. At least 20,000 hectares have been damaged by pest attack, which is spreading.

Abdul Jabbar Mia, Deputy Director of Netrakona AED, said they informed higher authorities and urged them to supply insecticides to control pest attack. But insecticides are yet to reach them, he said.

AED block supervisors and upazila agriculture officers have been asked to go to fields to advise farmers on pest management, but this will be of little help, he said.

As use of insecticides has proved ineffective, agriculture officials are advising farmers to kill the insects by using fishing net.

Netrakona Sadar Upazila Agriculture Officer Mohammad Shahjahan Chowdhury said the most common insect damaging the fields is locally called Pamri, which is virtually resistant to insecticides.