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Effect of Heat on Insects. Ole Dosland Technical Training Director. Zone Lethal Sub-optimum Optimum Sub-optimum Lethal. Temperature 120°F to 140°F 110°F to 115°F 95°F to 100°F 75°F to 90°F 65°F to 70°F 55°F to 60°F 35°F to 45°F -5°F to 10°F -20°F to -10°F.
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Effect of Heat on Insects Ole Dosland Technical Training Director
Zone Lethal Sub-optimum Optimum Sub-optimum Lethal Temperature 120°F to 140°F 110°F to 115°F 95°F to 100°F 75°F to 90°F 65°F to 70°F 55°F to 60°F 35°F to 45°F -5°F to 10°F -20°F to -10°F Temperature Insect Response Insect Response Death in minutes Death in hours Development stops Maximum development Development slows Development stops Death in weeks Most S.P.I’s die Death in minutes, insects freeze
Cold Treatment 0°F to 10°F Generally about a week Longer time due to reduced insect metabolism
Heat Treatment 120°F to 140°F Low humidity Shorter time due to increased insect metabolism
Heat Sterilization 160°F +++++ Quicker Harder on Equipment and Structures May Change Product or Material Performance
Effect of Heat on Insects • Heat Treatment Observations • On the run at around 100 degrees F. • On their backs (belly up) at around 120 degrees F. • Became crunchy at around 140 degrees F. in a few hours • Higher humidity seemed to delay heat stress effects • Heat Treatment Research Needed • Determine the lowest effective guideline for: • Temperature • Humidity • Time
Effect of Heat on Insects • Study # 1 - Slowly Increasing Temperature • Determine the lowest temperature needed to achieve mortality for a variety of insects
Heat Treatment Insect Study 12/94 Cockroach & Beetle Mortality110°F. to 120°F. for 60 Minutes Percent
Effect of Heat on Insects • Study # 2 - Length of Exposure • Determine the minimum time needed at the lowest temperature to achieve mortality for red flour beetle
Heat Treatment Insect Study 12/94 Red Flour Beetle Mortality118°F. to 120°F. at 26-27% RH for 20 Minutes Percent
Effect of Heat on Insects • Study # 3 - Humid Environment • Determine if humidity is a factor with the minimum time at the lowest temperature to achieve mortality for red flour beetle
Heat Treatment Insect Study 1/95 Red Flour Beetle Mortality118°F. to 120°F. at 75-76% RH for 25 Minutes Percent
Effect of Heat on Insects • Study # 4 - Survival Temperature • Determine the maximum survival temperature for red flour beetle
Heat Treatment Insect Study 1/95 Red Flour Beetle Mortality110°F. to 114°F. for 180 Minutes Percent
Summary & Conclusion • Minimum lethal temperature for adult German cockroach is 110 - 115° F. • Minimum lethal temperature for adult warehouse beetle is slightly less than the larvae lethal temperature of 118 - 120° F. • Minimum lethal temperature for adult red flour beetle is 116 - 120° F. • Minimum lethal heat parameters for adult red flour beetle is 116 - 120°F. for 15 - 20 minutes at 26 - 28% humidity
Summary & Conclusion • Higher humidity significantly reduces red flour beetle mortality at 116 - 120°F. for 15-20 minutes and is a factor in the use of heat for insect control. • Desiccation is probable means of death at 116 - 120°F. for 15 - 20 minutes at 26 - 28% humidity. • Adult red flour beetle can survive heat of 110 - 114°F. at 27 - 36% humidity for 3 hrs.
Suggestion • Results of this research indicates the following heat parameter is suggested as the lowest guideline for the control of most stored-product insects. TEMPERATURE of 120 - 125° F. at 25 - 30% HUMIDITY for 20 - 30 minutes
Zone Lethal Sub-optimum Optimum Sub-optimum Lethal Temperature 120°F to 140°F 110°F to 115°F 95°F to 100°F 75°F to 90°F 65°F to 70°F 55°F to 60°F 35°F to 45°F -5°F to 10°F -20°F to -10°F Temperature Insect Response Insect Response Death in minutes Death in hours Development stops Maximum development Development slows Development stops Death in weeks Most S.P.I’s die Death in minutes, insects freeze
Heat Heat (greater than 120 degrees F) can be used to de-infest empty facilities. No pesticide label or registration (chemical tolerances) is required for a heat treatment. With low humidity, large structural treatment can be done in 24 to 36 hours. Local area and equipment treatment usually can be done in 8 - 16 hours.
Effect of Heat on Insects • Thank You