The Sunflower Moth (Homoeosoma electellum) is an important pest on many varieties of stone fruit and other hosts. Sunflower Moths overwinter as pupae and adults typically emerge in late winter/ early spring may be seen soon after. There can be 1-3 generations in a year, depending on the weather. The Sunflower Moth Growing Degree Day Model, and available on the Pest Prophet app, is a tool growers can use to predict 1st and 2nd generations adult trap catches using field-specific temperature data.

Initiating the Biofix

To properly use the model, the biofix must first be set. This is the date that will serve as the starting point for growing degree day accumulation. For Sunflower Moths, this biofix is typically January 1st, for the Northern Hemisphere.

Growing Degree Day Accumulation and Treatment

After the biofix is set, growing degree day accumulation can begin, using a lower threshold of 13.3 C. This can be done using daily high and low temperatures, or using hourly temperature data using the Pest Prophet app. The first adult emergence will peak at approximately 1114 GDD (C) with the next generatino peaking at 2531 GDD (C).

Adjusting Biofix for Each Generation

For best results in second generation of Sunflower Moths in a given season, the biofix should be reset when new pheromone traps have successfully capture adult moths in late spring/ early summer.

Source:

Carlson, E. C., R. L. Witt and J. C. Miller. 1978. Tracing the flight activity of the sunflower moth. Calif. Agric. 32: 8-9.