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Insect & Pests

All Insect & Pests Content

Light colored fly with dark pattern on wings sitting on a green leaf.

Sunflower Receptacle Maggot Flies Spotted in Sunflower

Quite a few sunflower receptacle maggot flies have been spotted in South Dakota sunflower fields. The adults don’t feed on sunflower, but the larvae of this insect are considered minor pests of South Dakota sunflower.

Caterpillar with a red stripe on its back sitting on a green leaf. Bottom: Mottled gray caterpillar sitting on a green leaf.

Cutworms in Sunflowers

In South Dakota, some late-planted sunflower fields are having some cutworm pressure. Although most cutworm activity should be wrapped up by now, it is possible that some populations may have been feeding up until the beginning of July.

Green soybean leaf with small holes near the center and edges.

Redheaded Flea Beetles Active in Soybean

Redheaded flea beetles are active in soybean. Although they haven’t caused significant defoliation yet, their activity should be monitored.

Green caterpillar with a dark brown head.

Obliquebanded Leafrollers Active in South Dakota Soybean

If you’ve observed rolled soybean leaves that are held together by webbing, don’t immediately think thistle caterpillar. The obliquebanded leafroller caterpillar will roll soybean leaves and hold the leaf in place with silken webbing.

Small, green teardrop shaped insects on a green, soybean stem with pink flower.

Soybean Aphids Spotted in South Dakota

Soybean aphid populations have been observed in South Dakota. Although these populations are still very small, it is a good reminder that soybean aphid scouting should occur throughout the growing season to prevent population outbreaks and yield loss.

Two beetles. From left: Yellow beetle with a black head and three distinct black stripes on the back. Yellow beetle with a black head and twelve black spots on the back.

Start Scouting for Striped Cucumber Beetles

Striped cucumber beetles are showing up in gardens across South Dakota. If large populations are present in a garden, they can cause severe injury to squash, cucumbers, melons and other cucurbits if left unmanaged.

Wheat head with a green aphid, aphid mummies and a parasitized aphid.

English Grain Aphids Observed in Wheat

Reports of aphid populations in wheat fields have been slowly increasing in the past week. Most of these populations are well below the economic threshold, but there is a potential for them to increase.

Two mites. From left: Green leaf with two yellow spider mites with dark spots. Green leaf with yellow spider mite.

Spider Mites Reported in South Dakota Crops

With drought conditions continuing in South Dakota, it isn’t surprising that two-spotted spider mite infestations are being reported throughout the state. With hot temperatures in the forecast and limited chances for precipitation, we can expect spider mite populations to thrive in infested fields.

Dark-colored aphids on a green stem.

Cowpea Aphids Infesting Alfalfa

Typically, we worry about pea aphids in alfalfa. However, we noticed that cowpea aphids were present on alfalfa this week. If left unmanaged, cowpea aphids can stunt alfalfa, reduce yields and even kill the plants during severe infestations.

Alfalfa plant that has numerous holes in the leaves.

Keep Scouting for Alfalfa Weevils

This week we received a report and picture confirmation of early-instar alfalfa weevil larvae in an alfalfa field. Although most alfalfa fields were treated for alfalfa weevils before the first cutting, those fields still need to be scouted.