Neoseiulus fallacis is an important insect used for biological control of mites on a variety of crops. Researchers have developed a growing degree day model for Neoseiulus fallacis that can help predict adult emergence timing from eggs and nymphs, in order to improve pest management decisions.

Calculating Growing Degree Days

The Neoseiulus fallacis model uses a lower threshold of 54F and upper threshold of 90F. 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.

For this model, the “biofix” date, or date from which to start accumulating growing degree days, should be set to when Neoseiulus fallacis eggs are first observed or introduced to field.

Egg hatch occurs at approximately 40 GDD(F) after biofix date. First adult emergence occurs at approximately 135 GDD (F) after the biofix date. The model can then be used to prediction completion of up to 8 generations, as well as to approximate dispersal coverage.

Sources:

Dover, et al. 1979. Biological Control of Panonychus ulmi (Acarina:Tetranychidae) by Amblyseius fallacis (Acarina:Phytoseiidae) on Apple: a Prey-Predator Model. Environmental Entomology, Volume 8, Issue 2, 1 April 1979, Pages 282–292,