In vitro mortality of eggs and third instar larvae of Anastrepha ludens and A. obliqua with insecticidal atmospheres at high temperatures.
Yahia E. M., Ortega-Zaleta D.
Author Affiliation: DIPA, Facultad de Quimica, Universidad Autonoma de Queretaro, QRO, 76010, Mexico.
Acta Horticulturae : 779-786
Abstract : The in vitro mortality of eggs and third-instar larvae of Anastrepha ludens and A. obliqua was determined in air or in controlled atmospheres (CA) at high temperatures. Atmospheres evaluated were air, 0 kPa O2, 13 kPa O2+20 kPa CO2, and 0 kPa O2+50 kPa CO2 at 44°C for 160 min. Other treatments evaluated included 0 kPa O2+50 kPa O2 at 48°C for 160 and 220 min, and the same atmosphere at 40, 50, 51, 52, 54 and 55°C for 80, 160 and 240 min. Dry air at 44°C for 160 min caused very low mortality, and CA significantly increased the mortality. Higher temperatures caused a more rapid kill. A mortality of 100% was first achieved for the third instar larvae of A. ludens in air at 48°C, and then to third instar larvae of both species in CA at 48°C. A 100% mortality of eggs of A. ludens was achieved first in air and in CA at 51°C, and 100% mortality of eggs of A. obliqua was first achieved in air and in CA at 54°C A. obliqua was slightly tolerant than A. ludens, and eggs were more tolerant than third instar larvae in both species. There was a clear synergistic effect of CA at temperatures lower than 50°C, however, at 52 and 54°C CA was slightly less effective than air. We conclude that dry-hot air at ?44°C and 50% RH in CA (0 kPa O2+50 kPa CO2), for 160 min or longer, is effective in causing high mortality of eggs and third instar larvae of A. ludens and A. obliqua.