Sunflower Seed Maggot

Jul 17, 2015

By Janet J. Knodel

Extension Entomologist

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.

ent.knodel.1.pupae sunflower seed maggot

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.

Source: ndsu.edu

Video: Spring 2026 weather outlook for Wisconsin; What an early-arriving El Niño could mean

Northeast Wisconsin is a small corner of the world, but our weather is still affected by what happens across the globe.

That includes in the equatorial Pacific, where changes between El Niño and La Niña play a role in the weather here -- and boy, have there been some abrupt changes as of late.

El Niño and La Niña are the two phases of what is collectively known as the El Niño Southern Oscillation, or ENSO for short. These are the swings back and forth from unusually warm to unusually cold sea surface temperatures in the Pacific Ocean along the equator.

Since this past September, we have been in a weak La Niña, which means water temperatures near the Eastern Pacific equator have been cooler than usual. That's where we're at right now.

Even last fall, the long-term outlook suggested a return to neutral conditions by spring and potentially El Niño conditions by summer.

But there are some signs this may be happening faster than usual, which could accelerate the onset of El Niño.

Over the last few weeks, unusually strong bursts of westerly winds farther west in the Pacific -- where sea surface temperatures are warmer than average -- have been observed. There is a chance that this could accelerate the warming of those eastern Pacific waters and potentially push us into El Niño sooner than usual.

If we do enter El Nino by spring -- which we'll define as the period of March, April and May -- there are some long-term correlations with our weather here in Northeast Wisconsin.

Looking at a map of anomalously warm weather, most of the upper Great Lakes doesn't show a strong correlation, but in general, the northern tiers of the United States do tend to lean to that direction.

The stronger correlation is with precipitation. El Niño conditions in spring have historically come with a higher risk of very dry weather over that time frame, so this will definitely be a transition we'll have to watch closely as we move out of winter.