Characterization of the damage by the potato moths Tecia solanivora and Phthorimaea operculella (Lepidoptera: Gelechiidae) in Cartago, Costa Rica.
The damage caused by larvae of Tecia solanivora and Phthorimaea operculella is described, from observations in the main potato growing region of Costa Rica, during 1991-92, and laboratory analysis. Larvae of both gelechiids consumed 1 g of tuber tissue to complete their development. Damage was superficial but could penetrate deeper into the tuber at high densities and both species coexisted in the same tubers. The pests were active for the whole year, which was favoured by the continuous potato sowing in the area. The greatest damage occurred at the edge of the crop. Populations were highest in the dry season. P. operculella was a secondary pest in the area, while damage by T. solanivora could reach 90-100%. Generally, the population level was kept at 5% owing to 12-24 insecticide applications. It is concluded that the economic impact of the pest in the area was significant.