Melon Flies are an important economic pest on melons in some areas. Researchers have developed a growing degree day model for Melon Fly that can help predict when eggs will hatch, and the next generation of larvae will emerge.

Calculating Growing Degree Days

The Melon Fly model uses a lower threshold of 8.1 C. It can be calculated with daily high and low temperatures, using the sine model to estimate growing degree day units, or the Pest Prophet app can be used to calculate GDD accumulation from hourly temperature data for a specific field.

The “biofix” date, or date from which to start accumulating growing degree days, should be set when adults or eggs are first observed. After this the first new generation of larvae will begin to emerge at 22 GDD (C).

Sources:

Keck, C. B. 1951. Effect of temperature on development and activity of the melon fly. J. Econ. Entomol. 44: 1001-1002.