Pollinators Are Active in Sunflower

While scouting sunflowers, it’s hard to not notice the constant buzzing present in the field, which is produced by numerous species of bees. Flowering attracts pollinators to sunflower fields, but also is a time when insect pests are active on the heads and are managed using insecticides. Since the sunflower is a native of North America, there are numerous pests that can negatively impact it. These pests include the red sunflower seed weevil, banded sunflower moth, sunflower moth and other pests that may be present in the field.

Although insecticides are often necessary to reduce pest populations and prevent yield loss, it is important to consider the impact that they may have on beneficial insects, like pollinators. The best time to spray insecticides on sunflowers to avoid direct contact with pollinators is during the early morning or later afternoon/evening hours. Although some of these products may deter bee visitation, it is important to remember that broad-spectrum insecticides negatively affect all insects that are exposed to them.

Importance of Pollinators to Sunflower

The sunflower varieties grown in the United States were bred for self-fertility, but there is evidence that both honey bees and native wild bees can improve pollination. Sunflowers are visited by honey bees, as well as numerous species of native wild bees. For both confection and oilseed varieties, research has demonstrated that pollinator activity can improve yields.

What We’ve Observed So Far

In South Dakota, the most-abundant pollinators in sunflower fields are native bees. The most-observed species include Melissodes trinodis and Lasioglossum spp. These bees don’t have common names, but they are known to visit sunflowers. There were also many other species of bees that visited sunflower during flowering (Figure 1, Figure 2 and Figure 3). Like in other pollinator studies, honey bees were also observed, but they were not captured in great abundance. There is often confusion between identifying honey bees and M. trinodis, due to similarities in size and coloration. It’s important to remember that honey bees will have hair present on their eyes, whereas the other observed species won’t.