Occurrence and utilization of Trichogramma japonicum for white stemborer management
2004
Estoy, A.B. | Catli, A.E.D.,Philippine Rice Research Inst. (PhilRice Agusan). Basilisa, Remedios T. Romualdez 8611, Agusan del Norte (Philippines)
Regular monitoring and collection of white stemborer (WSB), Scirpophaga innotata egg masses at PhilRice Agusan Experiment Station was done to determine the occurrence of WSB egg parasitoids in the field. Results showed that WSB eggs were parasitized by three major parasitoid species namely Tetrastichus shoenobii, Telenomus rowani and Trichogramma japonicum. Out of 100 egg masses sampled, 96 percent were parasitized. Parasitism per egg mass was 59 percent and 14 percent, 21 percent and 24 percent was due to Tetrastichus, Telenomus and Trichogramma, respectively. The number of eggs obtained per egg mass was 114 (range 12-200 eggs/egg mass). Percentage egg parasitism was negatively correlated with the number of eggs per egg mass. In January-May 2003 cropping, 56 percent of the egg masses collected contained greater than 100 eggs/egg mass. Fifty percent of the egg masses had greater than 60 percent egg parasitism and this resulted in 2.46 percent (1.77-3.78 percent) whiteheads and yield of 4.75 t/ha (4.5-4.92 t/ha). In June-November 2003 cropping, artificial field release of T. japonicum at 60 days after transplanting (DAT) at the rate of 5 g/ha resulted in significant increase in parasitism from 12 percent to 27 percent egg parasitism 4 days after release. Partial budget analysis on the use of Trichogramma for WSB management resulted in P1045 net added benefits per hectare.
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