Effect of temperature on development and activity periods of the leek mothAcrolepiopsis assectella Zell. (Lep., Acrolepiidae)

Effects of temperature on egg, larval and pupal developmental times of the leek moth were examined at five constant temperatures ranging from 12 to 20 degreesC. Using this data, a linear degree-day model for the leek moth was developed. The model gave the threshold temperature of T-h = 6 degreesC, a nd 630 degree-days were required above the threshold temperature, to comple te the development of the leek moth. To validate the model in the field, fl ight activity during the summers of 1998 and 1999 was studied using pheromo ne traps. If the summer is warm the leek moth can have two generations per year in Sweden, but the probability of completing two generations within le ek plantations is very limited. The likelihood of the leek moth becoming a pest is highly dependent on access to alternative host plants for the first generation of leek moths.