During the survey of rice crop conducted by scientists of Punjab Agricultural University (PAU) in different districts of Punjab, incidence of planthoppers above economic threshold level (5 or more hoppers per hill) has been noticed at some locations, informed Dr G.S. Mangat, Head, Department of Plant Breeding and Genetics.
He further explained, “The brown planthoppers and whitebacked planthoppers feed at the base of plants and are often overlooked. Both nymphs and adults of these pests suck the cell sap from leaf and leaf sheath during these months.
The severely attacked rice plants ultimately dry up, on which a sooty mould appears. The crop dries up in patches. These dried up patches of the crop are called ‘hopper burn’. As the plants dry up, the hoppers migrate to the adjoining plants and in a few days, the areas of dry patches enlarge.”
Dr Mangat advised regular monitoring of rice fields for these planthoppers. The PAU recommended short duration varieties like PR 126, PR 124, Pusa Basmati 1509, PR 121, etc. would possibly escape the damage by planthoppers as these varieties are early maturing, he said. However, long duration varieties like Pusa 44 are more prone to hopper damage under the prevailing conditions and require regular monitoring to prevent any damage, he added.
For monitoring, few plants in the field should be slightly tilted and tapped 2-3 times at the base. If a minimum of 5 hoppers per hill are seen floating on water, the crop should be sprayed with any of the recommended insecticides viz. Chess 50 WG (pymetrozine) @ 120 g/ acre or Confidor 200 SL/ Crocodile 17.8 SL (imidacloprid) @ 40 ml/acre using 100 lires of water per acre, he advised. For better effectiveness, spray the crop thoroughly preferably using knapsack sprayer and hollow cone nozzle, he said.
Synthetic pyrethroids (cypermethrin, lambdacyhalothrin, deltamethrin etc.) should not be used on rice/basmati rice as these insecticides increase the population of planthoppers, he added.
Source:http://www.pau.edu/
