Bumble Flower Beetles And Sap Beetles In Sunflowers

Sep 30, 2013

This article was written collaboratively by Anitha Chirumamilla and Ada Szczepaniec.

It is past mid-September and sunflowers are nearing maturity with harvesting dates approaching. Beetles of various sizes are most commonly spotted on sunflowers during this time, and while there may be many of them, they are not considered sunflower pests. There are two beetles that are seen actively feeding on sunflower heads and appear to be of concern to producers while causing no damage to the crop. One of them is the bumble flower beetle (BFB), which belongs to the scarab beetle family. BFB’s are not pests of sunflowers as adults or larva and they do not cause any damage that is of economic concern. Chemical treatment is not recommended or needed for control. BFB’s are bigger in size measuring about ½ to ⅝ inches long, and come in different colors ranging from yellowish brown to dark brown with black spots on their forewings. Body and legs are covered with hairs, and the beetles make a loud buzz resembling that of bumble bees and hence the name BFB. Adults emerge from the overwintering sites in the soil during spring. Larvae are ‘C’ shaped grubs, which feed on the decaying organic matter in the soil and are often mistaken for June beetle larvae (pest of turf grass damaging the roots). Adult beetles feed on pollen and nectar of sunflowers and are attracted to the scent of infected plant tissue damaged by other insects and pathogens. The sight of these beetles feeding on the injured or infected tissue is often misleading, because they are not the cause of original damage.

Sap beetles are another group of beetles that are attracted to smell of secretions from wounded/diseased and ripened plant parts. In contrast to BFB’s, sap beetles are much smaller in size (⅛ to ¼ inch long) and dark colored with orange to yellow spots and bands on their body. They are easily identified by their antennae, which are club shaped (aka, the knobbed antennae), and their short wings exposing the tip of abdomen. Adult beetles overwinter in soil and emerge in spring. Eggs are laid near the vicinity of overripe or decaying plant matter which serve as feeding sites for hatching larvae. Sap beetles are not known to cause any damage in sunflowers, and no treatment is necessary to manage these insects.

Above: Bumble flower beetle feeding on dead tissue of sunflower. Photo credit: Anitha Chirumamilla

Video: Why Your Food Future Could be Trapped in a Seed Morgue

In a world of PowerPoint overload, Rex Bernardo stands out. No bullet points. No charts. No jargon. Just stories and photographs. At this year’s National Association for Plant Breeding conference on the Big Island of Hawaii, he stood before a room of peers — all experts in the science of seeds — and did something radical: he showed them images. He told them stories. And he asked them to remember not what they saw, but how they felt.

Bernardo, recipient of the 2025 Lifetime Achievement Award, has spent his career searching for the genetic treasures tucked inside what plant breeders call exotic germplasm — ancient, often wild genetic lines that hold secrets to resilience, taste, and traits we've forgotten to value.

But Bernardo didn’t always think this way.

“I worked in private industry for nearly a decade,” he recalls. “I remember one breeder saying, ‘We’re making new hybrids, but they’re basically the same genetics.’ That stuck with me. Where is the new diversity going to come from?”

For Bernardo, part of the answer lies in the world’s gene banks — vast vaults of seed samples collected from every corner of the globe. Yet, he says, many of these vaults have quietly become “seed morgues.” “Something goes in, but it never comes out,” he explains. “We need to start treating these collections like living investments, not museums of dead potential.”

That potential — and the barriers to unlocking it — are deeply personal for Bernardo. He’s wrestled with international policies that prevent access to valuable lines (like North Korean corn) and with the slow, painstaking science of transferring useful traits from wild relatives into elite lines that farmers can actually grow. Sometimes it works. Sometimes it doesn’t. But he’s convinced that success starts not in the lab, but in the way we communicate.

“The fact sheet model isn’t cutting it anymore,” he says. “We hand out a paper about a new variety and think that’s enough. But stories? Plants you can see and touch? That’s what stays with people.”

Bernardo practices what he preaches. At the University of Minnesota, he helped launch a student-led breeding program that’s working to adapt leafy African vegetables for the Twin Cities’ African diaspora. The goal? Culturally relevant crops that mature in Minnesota’s shorter growing season — and can be regrown year after year.

“That’s real impact,” he says. “Helping people grow food that’s meaningful to them, not just what's commercially viable.”

He’s also brewed plant breeding into something more relatable — literally. Coffee and beer have become unexpected tools in his mission to make science accessible. His undergraduate course on coffee, for instance, connects the dots between genetics, geography, and culture. “Everyone drinks coffee,” he says. “It’s a conversation starter. It’s a gateway into plant science.”