OFFICIALS this week warned farmers in provinces close to the Vietnamese border to take measures to protect their crops from an invasion of brown plant hoppers. Ngin Chhay, director of the Agriculture Ministry’s Rice Seedling Department, said yesterday that the insects migrate from Vietnam every year in mid-July. “Currently, the brown plant hoppers have invaded the rice seedlings of the farmers in some districts in Svay Rieng and Prey Veng provinces,” he said.