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As summer progresses into late summer, many parts of Texas experience prolonged periods of hot, dry weather with fewer rainfall events. These conditions not only place ornamental plants under drought stress but also create the perfect environment for spider mites to thrive. Unlike many insect pests that are suppressed by frequent rain, spider mite populations often explode during extended periods of dry heat, making August and September a critical time for greenhouse and nursery growers to intensify scouting efforts. The two-spotted spider mite (Tetranychus urticae) is one of the most common and economically important pests of ornamental crops. Feeding on more than 200 plant species, it attacks popular nursery and greenhouse crops including roses, hibiscus, lantana, marigold, salvia, verbena, hydrangea, and many bedding plants. Spider mites feed by piercing individual plant cells and removing their contents, producing characteristic yellow or white stippling on leaves. As infestations worsen, foliage develops a bronze appearance, leaves become dry and brittle, and severe infestations produce fine webbing that can cover leaves, stems, and flowers. Warm temperatures accelerate spider mite development, allowing a generation to be completed in as little as 7–10 days under favorable conditions. This rapid life cycle means that a few mites can quickly develop into damaging populations if left undetected. Dry weather also reduces the natural washing effect of rainfall, allowing mites to survive and reproduce unchecked. Routine scouting is the most effective defense. Inspect susceptible crops weekly, paying particular attention to the undersides of leaves where mites feed and lay eggs. A 10× hand lens can help detect early infestations before visible damage becomes widespread. Early detection allows timely intervention and greatly improves management success. An integrated pest management (IPM) approach provides the best long-term control. Maintain adequate irrigation to minimize plant stress, remove heavily infested plant material, and eliminate weeds that can serve as alternative hosts. In greenhouses, reducing excessive heat and maintaining appropriate humidity can help slow spider mite population growth. Biological control can be highly effective, especially in protected environments. Predatory mites such as Neoseiulus californicus provide excellent suppression when released early, before pest populations become established. Conserving these beneficials by selecting compatible pesticides is essential for successful biological control. When chemical control is necessary, rotate miticides with different modes of action to delay the development of resistance. Thorough coverage of the undersides of leaves is critical, as both mites and their eggs are concentrated in these protected areas. Late summer is the time when spider mites can quickly turn from a minor nuisance into a serious production problem. By combining vigilant scouting with cultural, biological, and chemical management tactics, growers can protect plant quality and minimize losses during one of the most challenging periods of the growing season.
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Texas has moved into summer earlier than usual, with high temperatures arriving well before the traditional peak season. While warm weather accelerates plant growth, it also creates ideal conditions for many insect and mite pests. For nursery growers, greenhouse producers, and landscape managers, early heat can mean earlier and more severe pest outbreaks. Many pests develop faster under high temperatures, allowing them to complete more generations in a shorter period. At the same time, heat and water stress can weaken plants, making them more susceptible to pest infestations. This combination often leads to increased pest pressure during early summer. Some of the most common pests to watch include spider mites, thrips, whiteflies, leafhoppers, and scale insects.
The best defense remains a strong Integrated Pest Management (IPM) program. Frequent scouting is critical during hot weather. Inspect plants regularly, especially new growth and leaf undersides, and use monitoring tools such as sticky cards or pheromone traps for early detection. In addition, minimizing plant stress through proper irrigation and balanced fertility can improve plant resilience. When treatments are necessary, rotate insecticides with different modes of action to help delay resistance development and preserve beneficial insects. Early detection and timely intervention are key. During hot summer weather, successful pest management starts with protecting plant health and staying proactive rather than reactive.  Rafia Khan, Ph. D.
Assistant Professor and Extension Specialist Texas A&M AgriLife Research and Extension Center, Overton, TX 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) |
AuthorTNLA Staff Archives
October 2026
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