Detection of moths and plants by infrared radiation (IR) is possible by night-flying moths. The thermal radiation emissivity of green plants is high (0.96) and that of a plowed field low (0.28). Four elements of the biosphere, temperature, atmospheric moisture, CO2 and O3 could hinder transmission.Corn earworm flight temperatures rise 3°C above ambient and at 25°C it would be broadcasting a chopped IR frequency of approximately 31 tetracycles. Water vapor is the principal attenuator of IR radiation. Data shows that moth activity decreases sharply with increases in actual water content of the air. Optimum temperatures and humidity are most likely to occur in spring and early summer between 21:00 and 04:00 hr. This coincides with the period of maximum corn earworm activity. Data indicates an inverse relationship between 03 and insect activity. Data from 4 sequentially programmed light traps indicate that flight behavior of insects is timed for the period of optimum reception by insect sensors.