AgNow | Feb 2025

n THE CARILLON STEINBACH, MAN. C6

n www.thecarillon.com THURSDAY, FEBRUARY 20, 2025

Agriculture Now

JOHN GAVLOSKI

Aphids pictured on peas near Carman.

Soybean aphids pictured on soybeans near Altona.

Battling the bugs: Manitoba’s top 10 insect concerns of 2024

4. Lygus bugs: A stealthy pest Lygus bugs, which puncture plants with their needle-like beaks and suck out the juices, were a problem in some canola fields. “In a dry year, they can be eco- nomically damaging because plants can’t compensate for the loss,” Gav- loski explained. “The tricky part is they move fast. If you’re not using a sweep net, you might not even know they’re there.” Threshold recommendations have changed. “We used to say 15 to 20 per sweep warranted spraying,” Gavlos- ki said. “Now, it’s closer to 30. In dry years, 20 might be enough. Below 17, they might even be beneficial, stim- ulating more pod production.” 5. Diamondback moths: A false alarm in 2024 Diamondback moths are tracked annually using monitoring traps. “We had some high counts in June, especially in the Eastern and Inter- lake regions,” Gavloski said. “But nothing significant happened. Rain- fall likely reduced their success.” 6. Cabbage Seedpod weevil: Expanding its range Cabbage seedpod weevils aren’t yet an economic concern, but their range is expanding. “We first detect- ed them in Manitoba in 2017,” Gav- loski said. “This year, we found them just west of Morris, which is the fur- thest east we’ve seen them. However, their populations remain well below economic thresholds.” 7. Sunflower pests: midge and moth Sunflower midge continued to cause edge damage in some fields, especially in the Eastern and Cen- tral regions. “There’s no spray for them, and they can create some nas- ty-looking heads,” Gavloski noted. Sunflower moth larvae, which tun- nel inside plants, also remained visi- ble. “You can see their frass, those lit- tle piles of ground feces. But there’s no registered insecticide for them yet.” 8. Armyworms: A migration-dependent threat Unlike many other pests, army- worms don’t overwinter in Manitoba. “They migrate intentionally, arriving in June and looking for dense grass- es,” Gavloski said. “We had some in- festations in the Central region and monitored them with traps.” 9. Aphids in small grains: Unpredictable but impactful Aphids don’t overwinter in Mani- toba either, making them difficult to

be complacent.” 2. Cutworms: A cyclical challenge Cutworms follow population cy- cles, peaking every few years before declining. “If you recall, 2019 and 2020 were bad cutworm years,” Gav- loski said. “Since then, populations have been declining, but there were still cases of spraying in almost every agricultural region last year.” Different cutworm species cause varying damage. “Dingy cutworms are tricky because they climb and feed at night,” Gavloski explained. “You’ll see defoliation, but no in- sects, because they burrow under- ground by day.” In contrast, redback cutworms sever plants at the base, leaving obvious damage. Seed treatments can offer protec- tion, but wet conditions can reduce their effectiveness. “These treat- ments are water-soluble, so if there’s heavy rain, they won’t last as long,” he warned.

by LORI PENNER I nsects troubling to farmers ha- ven’t changed much since 2024, but at St Jean Farm Days, Mani- toba Agriculture entomologist John Gavloski shared which critters to watch for, which have made it back on the annual top 10 list and which one is no longer considered a top threat. As someone who has monitored agricultural pests for decades, Gav- loski provides invaluable insights to farmers, agronomists, and those working in agriculture. “It’s a similar list to last year’s,” Gavloski noted. “The main differ- ence is that Bertha armyworm made it back on the list, replacing dia- mondback moths, which weren’t as much of an issue this year.” While some insect populations have declined, others have surged, demanding vigilance from Manito- ba’s producers. Here’s a breakdown of the most concerning pests of 2024. 1. Grasshoppers: Persistent but manageable Grasshoppers thrive in hot, dry conditions. While their numbers were lower in 2024 compared to 2023, some areas still required man- agement. “They overwinter as eggs and need some moisture to hatch,” Gavlos- ki explained. “But they have to eat immediately to build up their fat re- serves to become a nymph. If they don’t, they either starve or become more vulnerable to disease.” Two-striped grasshoppers were the dominant species in last year’s surveys. “They’re general feeders, so keep an eye on them,” Gavloski ad- vised. “Our August surveys showed good egg-laying conditions, so don’t

LORI PENNER THE CARILLON John Gavloski, an entomologist with Manitoba Agriculture, recently shared his annual list of the top 10 insect concerns affecting Manitoba’s crops in 2024.

predict. “They get blown in, so their impact varies each year,” Gavloski explained. In 2024, English grain aphids were first spotted in late May, and oat-bird cherry aphids appeared in June. Some areas experienced high populations, prompting insecticide applications, particularly in oats and wheat in the Northwest and Eastern regions. 10. Bertha armyworm: Making a comeback Bertha armyworm replaced dia- mondback moths on this year’s top 10 list. “It wasn’t an issue last year, but we saw more cases this year, par- ticularly in canola,” Gavloski said. Monitoring and management Gavloski’s message to producers is clear: scouting remains the best de- fense against insect pests. “Some of these insects come in cycles, some arrive unpredictably, and others are always around in low

numbers,” he said. “Knowing what’s in your field, when they appear, and what their thresholds are can save you a lot of trouble - and money.” Manitoba Agriculture’s monitor- ing programs, weekly pest updates, and ongoing research provide essen- tial support to those on the front- lines of crop production. By staying informed and vigilant, farmers can minimize losses and ensure a suc- cessful growing season in the face of these persistent insect threats.

JOHN GAVLOSKI Flea beetles pictured on canola near Carman.

3. Flea beetles: A chronic issue Flea beetles continue to plague canola growers across Manitoba. “Almost every region saw spraying, and some fields had to be reseeded,” Gavloski said. “The issue last year was that cool temperatures slowed plant growth, prolonging the vulner- able seedling stage.” He emphasized that if canola reaches the three- or four-leaf stage within three to four weeks, seed treatments usually provide adequate protection. “But if it takes longer, those treatments wear off, leaving plants exposed.”

JOHN GAVLOSKI Grasshoppers pictured on corn near Carman.

JOHN GAVLOSKI\ Redback cutworms pictured near Elm Creek.

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