Insect & Pests

All Insect & Pests Content
Mosquito resting on a dandelion seed head.

West Nile Virus Update: Aug. 2, 2021

As of Aug. 2, 2021, the South Dakota Department of Health indicated that West-Nile-virus-positive mosquitoes were detected in Brookings, Codington, Hughes, Lincoln and Brown counties in South Dakota.

Red-brown colored weevil with bent antennae originating on the elongated mouthparts.

Red Sunflower Seed Weevils Are Active

Red sunflower seed weevils are active in South Dakota sunflowers. We noticed that many fields at R5 stages are already being sprayed, but scouting should still continue in those fields after application, and it should begin for fields that will reach the R5 stage within the next week.

Adult twospotted spider mites crawling on webbing that is attached to a leaf

Two-Spotted Spider Mite Populations Reaching Threshold

Drought conditions have continued and worsened in much of South Dakota during this season. As a result, two-spotted spider mite populations have been present in most fields and have recently had large population growth in soybean fields throughout the state.

Brown snailcase bagworm cases on the white underside of a jar lid.

Snailcase Bagworms in South Dakota

A unique insect that has been observed in South Dakota is the snailcase bagworm. Snailcase bagworms are wingless moths that spend their entire life in spiral-shaped “snail” cases, which they build around themselves using a combination of silk, soil particles and fecal matter.

a black beetle covered in a white substance

Gray Sunflower Seed Weevils

Gray sunflower seed weevils have been spotted in sunflower fields this week. Although they are a non-economic pest there are times when they can have population outbreaks and reduce sunflower yields.

A beetle with an orange head.

Zonitis Bilineata on Sunflowers

While scouting sunflower last week we noticed beetles that were present throughout the field on the developing buds. These beetles weren’t feeding on the buds or the bracts that they were often on. So, what were they doing on the sunflowers?

A group of people in a soybean field with white insect nets

SDSU Extension to Offer Integrated Pest Management Field School Online

July 30, 2021

South Dakota State University Extension will kick off its 13th annual Integrated Pest Management (IPM) Field School Aug. 1.

Cream mite on a green-colored caterpillar.

Straw Itch Mites

Straw itch mites, also known as hay mites or grain mites, can be a major problem when present in hay or grain. The best way to avoid a straw itch mite infestation is to keep commodities at low moisture levels and bale straw when it is thoroughly dry.

Small black beetles covering a partially defoliated leaf.

Flea Beetles Causing Issues in Canola

Large flea beetle populations in canola have been observed in neighboring states and within South Dakota. The hot, dry and sunny conditions that we have been experiencing throughout 2021 have been ideal for flea beetle populations.

Cream-colored moth with a dark brown band in the middle of its body.

It’s Time To Start Scouting For Banded Sunflower Moths

Sunflowers throughout South Dakota are quickly approaching the R3 growth stage, which means it’s time to start scouting for banded sunflower moths. Banded sunflower moths are capable of reducing yields due to their caterpillars feeding on the bracts, florets and seeds.