Sunflower Seed Maggot

 

Sunflower heads damaged from sunflower seed maggot, Neotephritis finalis, are being observed in some sunflower fields near Mandan. Adult flies emerge in July and lay eggs on incompletely opened sunflower inflorescences. Larvae feed for about 14 days and tunnel through the developing head causing seed sterility and deformed heads (see photo). The small, brown pupae can be found on the face of sunflower heads, usually surrounded by a small number of damaged florets. There are two complete generations per year of the sunflower seed maggot in North Dakota.

 

 

 

 

For management, late planting date (early to mid-June) was found to reduce damage ratings and percentage of damaged heads for N. finalis compared to early planting dates (mid- to late May) (Knodel et al. 2011. JEE 104: 1236-1244). Visual observations of adult N. finalis showed that the majority of flies were found in the early planted sunflower (78.2 %) compared to the late planted sunflower (21.8%). Research on different insecticide mode of actions [pyrethroid insecticide (Asana XL), an organophosphate insecticide (Lorsban) or a combination of an organophosphate + a pyrethroid insecticide (Cobalt)] and application timings (R1, R3, R5, and R1+R3+R5.1 growth stages) did not provide adequate control of adult N. finalis. Even three different insecticide timings applied at crucial periods of sunflower head development (R1+R3+R5.1) did not reduce the damage from N. finalis.