Lower development treshold and thermal constant in the German cockroach, Blattella germanica (Blattodea: Blattellidae)

The effect of temperature on the development of the first instar of Blattella germanica was studied at four constant temperatures of 21, 24, 27 and 30 deg C in temperature controlled chambers. The temperature dependence of the developmental rates and the thermal thresholds were established by means of linear regression. The pooled data reveal that the lower thermal threshold for the development of the B. germanica is 16.2 deg C and the thermal constant (first instar) is 93.3 day-degrees. We introduce the term "safe temperature" (ts) which indicates the temperature to be maintained in stores or food premises in order to prevent development of a pest species (i.e. ts LDT). For B. germanica we recommend a ts 15 deg C.