 Rafia Khan, Ph. D. Texas A&M AgriLife Research and Extension Center Overton, Tx. Winter freezes often bring hope that cold weather will eliminate insect pests in landscapes and nurseries, offering a natural reset before the next growing season. After several nights of subfreezing temperatures, it is common to expect fewer insects and reduced pest pressure in spring. While freezing temperatures can suppress or temporarily reduce some exposed pest populations, they rarely provide complete control. Many insects are surprisingly resilient and well-adapted to surviving winter conditions through protective behaviors and physiological adaptations, allowing them to rebound quickly once temperatures warm.
Insects are exothermic or cold-blooded; their activity slows as temperatures drop. Feeding, reproduction, and development pause, and extreme cold can kill exposed individuals. However, many species avoid lethal temperatures by seeking protection in soil, mulch, bark crevices, plant crowns, or greenhouse structures. These microhabitats stay warmer than the surrounding air, thereby improving survival. Many insects can survive through dormancy (diapause) or by producing “antifreeze” compounds such as glycerol, sorbitol, antifreeze proteins, etc. that protect their tissues from freezing injury. Eggs, pupae, scales, borers, and soil-dwelling pests are especially resilient. As a result, even after a hard freeze, enough individuals often survive to quickly rebuild populations in spring. Freezes may temporarily suppress exposed pests such as aphids or caterpillars, but they should not be relied upon as a primary management tool. Warmer temperatures can lead to rapid reproduction and early-season outbreaks. Instead, winter is an ideal time to strengthen integrated pest management (IPM) practices. Remove plant debris, prune heavily infested branches, inspect bark and crowns for overwintering stages, and consider dormant oil applications for scales, mites, and aphids. Continue monitoring in greenhouses where pests may survive year-round.
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Rafia Khan, Ph.D. Assistant Professor and Extension Specialist Texas A&M AgriLife Research and Extension Center, Overton, TX Winter can feel like a break from pest pressure, but for nursery and greenhouse growers, many insects are still present and waiting for the right conditions. Protected structures, mild winter weather, and overwintering life stages allow many pests to survive on plants, in pots, in growing areas, in debris, and in weeds. If these pest populations are not addressed, they often resume early and aggressively in spring. Common winter pests include aphids, thrips, mealybugs, scale insects, whiteflies, spider mites, and greenhouse moth pests such as the European pepper moth. These insects can survive on plant material, in potting media, or within greenhouse structures, often going unnoticed until populations increase. Programmed scouting remains the foundation of winter Integrated Pest Management (IPM). Monitoring efforts should be focused on current in-house plants and newly arrived plant material. Inspect leaf undersides, stems, and growing points, and use sticky cards to detect flying insects early. Cultural practices play a key role in reducing pest pressure during winter. Sanitation, such as the removal of plant debris, leftover shipped plants, weeds, volunteer plants, and unused containers, should be removed from the production sites as they may harbor pests. Manage irrigation carefully to avoid conditions favorable for fungus gnats and root pests, and inspect incoming plants before placing them into production areas. When treatments are necessary, applying products strategically and rotating insecticide modes of action helps protect product performance and avoid costly resistance issues. Winter is also the best time for growers to step back and evaluate what worked and what didn’t during the past season. Reviewing pest records, adjusting management plans, and training employees to recognize early pest signs can pay off quickly. Investing time in winter pest management reduces carryover populations, improves plant quality, and helps operations enter spring with fewer surprises and lower control costs. Figure: Some greenhouse pests in winter. European pepper moth larva (A) and adult (B), Thrips (C), and mealybug (D)Your voice matters. Right now, two surveys are open that will shape decisions directly affecting Texas nurseries, greenhouses, and landscapers. We encourage all members to take a few minutes to participate so our industry’s needs are represented. 1) IR-4 Priority Setting Survey (Due Aug 29 The IR-4 Environmental Horticulture Program is setting its national research priorities for the next two years, and grower input will determine which pest, disease, and weed issues get funded. Right now, 75% of survey responses are from cut flower growers. If nursery and greenhouse producers don’t participate, our day-to-day challenges may not be reflected in IR-4’s plan. What we’re asking:
2) Native Tree Availability Survey (Due Sept 5) Upcoming local rulemaking may impact tree planting and availability. To prepare, TNLA is gathering marketplace data to show what species are realistically available.
What we’re asking:
Thank You for Taking Action Both of these surveys are short, but the impact is significant. By participating, you ensure the voice of Texas growers and retailers is part of the larger conversation shaping our industry’s future. |
AuthorKim Cabrera, TNLA Marketing Manager Archives
February 2026
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