Parasites Help Control Rice Black Bug Population
The Rice Black Bug infests rice plants at all stages of growth. This is why it could be considered as one of the most difficult rice pest to control. But according to studies conducted in Agusan, the bug wouldn’t he a serious concern if properly managed.
In studies led by PhilRice crop protection specialist Elisco H. Batayan, it was observed that soon after the black bug egg mass population reaches its peak, egg parasitism also subsequently reaches its peak.
The experiment was conducted in farmers fields in Kitcharao, Agusan del Norte and Esperanza, Agusan del Sur, where NSIC Rc122 and PSB Rc82 were used as test varieties since these are among the popular varieties in the Caraga region.
In Esperanza, the egg mass population in direct-seeded rice started to increase at 8 weeks after seeding (WAS) and reached its peak at 11 WAS. The rice black bug nymphs started to colonize the rice plants at 9 WAS and reached its apex at 11 WAS. On the other hand, the population of adult black bug declined from 3 WAS until 7 WAS, started to increase again at 8 WAS and reached its peak at 11 WAS.
The culminating point of the egg mass population in transplanted rice was at three weeks after transplanting (WAT). Then declined until 7 WAT, peak at nine WAT, and decreased thereafter. The population of the nymphs, on the other hand, had four peaks: 3 WAT, 5 WAT, 9 WAT, and 11 WAT, which was the highest one. The apex of the adult population was at three, nine, and 11 WAT.
Egg parasitism in direct-seeded rice was observed at nine WAS. It gradually increased thereafter and reached its peak at 11 WAS with 18.26 percent parasitism. On the other hand, egg parasitism in transplanted rice had three peaks: 5 WAT, 8 WAT, and 10 WAT.
The results indicated lower egg parasitism in direct-seeded rice than transplanted rice. Batayan said this could be due to the poor ability of the adult parasite in locating its host (the eggs) in direct seeded rice. He added that in transplanted rice, the parasite could easily transfer from one hill to another, making more efficient in finding its host.
Popularity: 5%
Popularity: 5%
