Mortality of eggs and third instar larvae of Anastrepha ludens and A. obliqua with insecticidal controlled atmospheres at high temperatures
Elhadi M. Yahia and Dora Ortega-Zaleta
Postharvest Biology and Technology Vol: 20 Issue: 3 Pages: 295-302.
2000
บทคัดย่อ
The in vitro mortality of eggs and third instar larvae of Anastrepha ludens
and A. obliqua was determined after exposure to 21 treatments of
air or controlled atmospheres (CA) at high temperatures and 50% RH. Air at 44°C
for 160 min caused very low mortality, which increased significantly by CA.
Higher temperatures caused a more rapid kill. One hundred percent mortality was
achieved for third instar larvae of both species in air or CA at 48°C for 220
min. A 100% mortality of eggs of A. ludens was achieved in air at
51°C for 240 min or in CA at 52°C for 240 min, and 100% mortality of eggs of A.
obliqua was achieved in air or in CA at 55°C for 240 min. A. obliqua
was slightly more tolerant than A. ludens, and eggs were more
tolerant than third instar larvae in both species. CA had a synergistic effect
at <50°C, but was slightly less effective than air at higher temperatures.
Low O2 concentrations were more effective than high CO2
levels. The mean estimated temperatures for 50, 99 and 99.9968% mortality (LT50s,
LT99s, LT99.9968s) of eggs of A. obliqua
(the most tolerant) exposed to 0 kPa O2+50 kPa CO2 for
240 min were 49.4, 54.8 and 60.9°C, respectively. 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 increasing mortality of eggs and third instar larvae of
A. ludens and A. obliqua.