Fate of the Released Trichocards in Sugarcane Vis-a-vis Ant Predation

The egg parasitioid Trichogramma chilonis is released as Trichocards during inundative releases against sugarcane borers. A study was undertaken to assess the fate of these cards in the field after their release. Results revealed that the eggs, whether they were unparasitized or freshly parasitized or those had turned black due to parasitization had failed to deter the predators, regardless of the age of the crop on which the cards were placed. In the present study, the ant species found predating on the eggs in the Corcyra cephalonica cards and Trichocards were Monomorium aberrans Forel., Camponotus compressus F., and Solenopsis geminata (F.). The predation did not vary based on the time interval allowed to lapse in the field. These findings show that the predator activity was random and that the encounter was by chance. When the cards were placed in net bags and tied to the plant, there was complete protection of the Corcyra cards and Trichocards. However, the time required for handling and tying these guarded bags for each release rendered it impractical. Hence, the Trichocards should either be released after the cards show at least 2% of the parasitoid emergence or had completed emerging just before release, to have maximum safety on the field.