Anagrus epos is an important insect used for biological control of blackberry leafhoppers. Researchers have developed a growing degree day model for Anagrus epos that can help predict adult emergence timing from eggs and nymphs, in order to improve pest management decisions.

Calculating Growing Degree Days

The Anagrus epos model uses a lower threshold of 45F. 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 Anagrus Epos eggs are first observed or introduced to field.

First adult emergence occurs at approximately 440 GDD (F) after the biofix date. Egg-laying will begin at 487 GDD(F) after the biofix date.

Sources:

Williams, D. W. 1984. Ecology of the blackberry-leafhopper-parasite system and its relevance to California grape agroecosystems. Hilgardia 52: 1-32.