Cutworms Active

May 06, 2016

By Janet J. Knodel

Army cutworm and pale western cutworm have been reported feeding on winter wheat and weedy cultivated fields in NW and SW North Dakota.

The army cutworm larvae are gray to brown with the back side (top) darker than the ventral side (bottom) with a pale mid-dorsal line. It is a climbing cutworm that “grazes” on the leaves of its host plants. When defoliation is limited, plants can recover from army cutworm feeding. Army cutworm larvae observed recently in ND were mature (1.5-2 inches long) and have completed most of their development and feeding injury. So, no control is recommended for mature larvae that are at the end of their development and feeding period. These larvae will be pupating (resting and non-feeding stage) soon in the soil. Army cutworm moths will emerge in June and fly to the Rocky Mountains for a period of inactivity. From late August to late October, the moths become active and fly back to the plains to lay eggs in soft soil of freshly cultivated weedy fields or newly seeded winter wheat fields. In the north central plains states, army cutworms are primarily an early season pest of cereal crops, especially winter wheat in the Dakotas and Montana.

The pale western cutworm overwinters as eggs which hatch into larvae as soon as the spring temperatures warm up to 50F. Pale western cutworm larva are about 1½ inch long when mature, and pale yellow with a white mid-dorsal line and two black inverted ‘V’s on head. They feed subterranean on plant stems below the ground. If the growing point is destroyed from larval feeding, plants will not survive and feeding injury results in stand loss.

Field scouting for cutworms is critical and should begin as soon as crops emerge, and fields should be checked at least twice per week until approximately late June or until the crop is no longer susceptible (past early growth stages). Cutworm damage symptoms are foliar defoliation or cut / wilted plants, leading to bare patches in the field. Examining 100 plants per five sampling sites by walking a ‘W or V’ pattern for a total of 500 plants in a field. Use a trowel to dig around damaged plants to determine if cutworms are present in soil or field debris. A missing plants in a row does not necessarily indicate cutworm larval damage; for example, gaps may be caused by a defective planter, poor germination, rodents or birds.

The size of the cutworm larvae should also be estimated. Small larvae pose the greatest potential for crop damage as they still have to feed and grow larger.

The economic threshold for cutworms varies by crop. Here’s some of the thresholds for North Dakota field crops:

Alfalfa – 3 to 4 larvae per square foot (new stands – only 2 per square foot)

Canola – 1 larvae per 3 feet of row

Chickpeas / Field Peas / Lentils – 2 to 3 larvae per square meter

Corn – 3 to 6 % of the plants are cut

Small grains – 4 to 5 larvae per square foot

Soybean - 1 larva per 3 feet of row or when 20% of plants are cut

Sugarbeet – 3 to 5 larvae per square foot or 4 to 5% cutting of seedlings (young beets)

Sunflower - 1 larva per square foot or 25 to 30% stand reduction

Several different insecticides are registered for cutworm control. Post emergent foliar insecticide treatment provides rapid knockdown of surface feeding cutworms. Optimal control is achieved when insecticide applications are made at night when cutworms are active feeding. Wet soil conditions also will improve insecticide efficacy, as cutworms feed near the soil surface in these conditions. Please consult the 2016 ND Field Crop Insect Management Guide. Insecticide seed treatment products, such as Cruiser (a.i. thiamethoxam), Gaucho (a.i. imidacloprid), and Poncho (a.i. clothianidin) are only labeled for cutworm suppression, not complete control.

Source: ndsu.edu

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.”