Tag: ornamental entomology

Mealybugs remain one of the most persistent and costly pests in greenhouse ornamentals. Their waxy covering, protected feeding sites, cryptic diagnostics, and overlapping generations make them difficult to suppress with insecticides alone. Recent work from Clemson University provides growers with a clear, practical roadmap for integrating biological control with selective chemistries without undermining either tool.

This synthesis is based on two complementary publications:

• Tan & Ahmed (2026) – A Practical, Compatible Strategy for Greenhouse Mealybug Management (GrowerTalks, Aug. 31, 2026) Available at: https://www.growertalks.com/Article/?articleid=28194
• Ahmed, Tan & Mondal (2027) – Greenhouse Mealybug Management Guide for Growers (GrowerTalks IMF Guide 2027, pp. 7–8) Available at: https://www.growertalks.com/pdf/IMF2027_Guide.pdf

Together, these pieces distill what growers can reliably use and how to deploy those tools in a compatible, stage‑aligned program.

Biological Control: What Actually Works in Greenhouses

Across commercial suppliers, only a small set of biological agents consistently perform against citrus, Madeira, long-tailed, and striped mealybugs:

• Cryptolaemus montrouzieri (mealybug destroyer)
• Chrysoperla spp. (lacewings)
• Micromus variegatus
• Parasitoids (Anagyrus pseudococci, Leptomastix dactylopii, Leptomastidea abnormis)
• Entomopathogenic fungi (Beauveria bassiana, Isaria fumosorosea)

These are the tools growers can realistically access and integrate.

Chemical Tools: Selectivity Determines Compatibility

Many broad-spectrum insecticides (IRAC 1A, 1B, 3A, 4A) suppress mealybugs but also harm predators and parasitoids, even as dried residues. Clemson’s synthesis highlights selective chemistries that maintain compatibility:

• Buprofezin (IRAC 16)
• Pyriproxyfen (IRAC 7C)
• Flonicamid (IRAC 29)
• Afidopyropen (IRAC 9D)
• Pyrifluquinazon (IRAC 9B)
• Spirotetramat (IRAC 23)

These materials repeatedly show low direct toxicity to adult predators and minimal disruption when used thoughtfully.

Additional diagnostic and species‑specific guidance is available in Mondal et al. (2025), which outlines practical identification keys, IR‑4 efficacy patterns, and management considerations for citrus, Madeira, Mexican, Phormium, and root mealybugs.

Timing Is the Key to Compatibility

Growers often ask for a simple “safe vs. unsafe” list, but compatibility depends on when and how materials are used:

• Apply selective insecticides early, before predator release.
• Introduce Cryptolaemus or lacewings when populations are moderate, not explosive.
• Use spot treatments to preserve predators.
• Allow residues to decline before reintroducing biological control if a reset spray is necessary.

This timing‑based approach is the core of both GrowerTalks articles.

Operational Takeaways for Growers

• Cryptolaemus remains the cornerstone predator for greenhouse mealybugs.
• Lacewings provide supplemental pressure on crawlers.
• Selective chemistries allow growers to intervene without disrupting biological control.
• Integrated programs are most successful when pesticides and predators are used together, not in competition.
• Compatibility is achieved through selectivity + timing, not by avoiding chemicals altogether.

References 

Ahmed, M.Z., Tan, P., & Mondal, P. 2027. Greenhouse Mealybug Management Guide for Growers. In: GrowerTalks 2027 Insecticide, Miticide & Fungicide Guide, pp. 7–8. Available at: https://www.growertalks.com/pdf/IMF2027_Guide.pdf

Mondal, P., Tan, P., & Ahmed, Z. 2025 Effective mealybug control strategies for greenhouse growers. In: Greenhouse Management 2025, August 8, 2025. Available at: https://www.greenhousemag.com/article/managing-mealybugs-pest-control-greenhouse/

Tan, P., & Ahmed, M.Z. 2026. A Practical, Compatible Strategy for Greenhouse Mealybug Management. GrowerTalks, August 31, 2026. Available at: https://www.growertalks.com/Article/?articleid=28194

Figure Caption: Mealybugs turning ornamentals into an all‑you‑can‑eat buffet. Compiled by Zee Ahmed (Clemson University).

Over the past six months, Ahmed Lab has assembled the most comprehensive, side‑by‑side database of whitefly efficacy data available for ornamental crops. This effort—led by Dr. Zee Ahmed (PI Turf and Ornamental Entomology Lab at Clemson) and his Ph.D. student, Powlomee Mondal—consolidated 15 years of published greenhouse trials across multiple crops, biotypes, and chemistries. The goal was to give growers a clear, evidence‑based picture of what consistently works, especially against the MED/Q biotype that challenges poinsettia production every Christmas season. This synthesis appears in the May 2026 Poinsettia Special Issue of GrowerTalks. The summary below highlights the key findings for Clemson IPM stakeholders as the new poinsettia season begins.

Whiteflies remain one of the most persistent and costly pests in greenhouse ornamentals. Across 15 years of trials, a consistent pattern emerges: only a small group of products repeatedly delivers high control, and their value depends on precise placement within the poinsettia crop cycle.

High‑Efficacy Products Are Few (Table 1)

Table 1 summarizes 15 greenhouse trials across salvia, zinnia, basil, hibiscus and poinsettia. Reported efficacy ranged from –45% to 99%. Only four products consistently reached ≥90% efficacy:

• Cyantraniliprole (IRAC 28)
• Dinotefuran (IRAC 4A)
• Pyrifluquinazon (IRAC 9B)
• Afidopyropen (IRAC 9D)

Two microbial agents—Beauveria bassiana GHA and BW149—also exceeded 90% efficacy in hibiscus trials. These materials repeatedly suppressed whiteflies across crops, biotypes and growing conditions, including MED/Q.

MOA Patterns Are Consistent (Table 1)

High‑performing products were concentrated in three MOA groups:

• IRAC 28 – ryanodine receptor modulators
• IRAC 4A – neonicotinoids
• IRAC 9B/9D – feeding disruptors

Other MOA groups showed low to moderate performance. Microbials were the only consistent exception.

Neonics and Poinsettias

Dinotefuran was the only neonicotinoid in Table 1 that consistently reached ≥90% efficacy. Other IRAC 4 subgroups (4C, 4D) performed moderately.

Poinsettias do not present a pollinator exposure pathway under commercial greenhouse conditions. Growers following “non‑neonic” programs can rely on pyrifluquinazon, afidopyropen and microbials without losing efficacy.

Crop Stage Determines Fit (Figure 1)

Figure 1: Whitefly chemical control guide for poinsettia production.

Table 1: Summary of chemical and microbial products evaluated for whitefly management across ornamental crops.

Figure 1 integrates efficacy patterns from Table 1 with poinsettia crop physiology. Product fit aligns with predictable stages:

• Rooting – highest sensitivity; microbials preferred
• Early vegetative – canopy expansion; afidopyropen fits well
• Post‑pinch – rapid regrowth; strongest chemistries needed
• Mid‑season – highest whitefly pressure; high‑efficacy products essential
• Finish – bract development; residue and phytotoxicity risk dominate

Figure 1 shows that cyantraniliprole, dinotefuran and pyrifluquinazon align with post‑pinch through mid‑season, when pressure is highest and tissues are less sensitive. Stage‑Aligned Rotation (Figure 1)

The Early–Bridge–Peak–Clean rotation directly reflects the stage‑based fit patterns in Figure 1:

Early (Rooting → Early Vegetative)

• Beauveria bassiana (GHA or BW149)
• Afidopyropen as canopy expands

Bridge (Early Vegetative → Post‑Pinch)

• Afidopyropen maintains suppression

Peak (Post‑Pinch → Mid‑Season)

• Cyantraniliprole
• Dinotefuran
• Pyrifluquinazon

Clean (Finish)

• Beauveria bassiana
• Softer chemistries to protect bracts

This sequence distributes selection pressure, prevents mid‑season population spikes and avoids late‑season residue issues.

Operational Conclusions

• Table 1 shows that high‑efficacy products are limited and must be protected.
• Figure 1 demonstrates that MOA rotation only works when aligned with crop stage.
• Performance is active‑ingredient specific, not MOA‑wide.
• Early suppression—not late intervention—determines finish quality.
• Microbials remain essential at rooting and finish due to plant sensitivity.

Fifteen years of greenhouse data converge on a single conclusion: whitefly management succeeds when the strongest tools are deployed at the correct crop stages and overuse of any single chemistry is avoided.

Citation

Ahmed MZ, Mondal P (2026). Fifteen Years of Whitefly Control: Cutting to the Chase. GrowerTalks 9(1), May 2026 Issue. Available at: https://www.growertalks.com/Article/?articleid=27982 (Accessed May 4, 2026).

Acknowledgment

We thank James E. Faust (Clemson University), Erfan Vafaie (formerly Texas A&M University), JC Chong (SePRO Corporation), Jay Mitchell (Mitchell’s Nursery & Greenhouse Inc.), Luke Venable and Amanda Blayton Thompson (Forest Lake Greenhouses) for their helpful comments.

The spotted lanternfly (SLF) has been established in 19 U.S. states since its first detection in Pennsylvania in 2014. It was confirmed in North Carolina in 2022, Tennessee in 2023, Georgia in 2024 and South Carolina in 2025. While other neighboring states in the southeastern U.S. don’t yet have confirmed established populations, the risk of establishment remains high.

Dr. Zee Ahmed (Clemson University) and his colleagues—Dr.   Shimat Joseph (University of Georgia), Dr. Midhula Gireesh (University of Tennessee), Karla Addesso (Tennessee State University) and Alejandro Del Pozo-Valdivia (Virginia Tech) developed a management calendar to support early detection and proactive control efforts for ornamental growers in the Southeastern U.S. This seasonal framework offers practical guidance to help growers address SLF concerns proactively from late summer 2025 through summer 2026.

Here is the link  Spotted Lanternfly Management Calendar for Ornamental Growers in the Southeastern U.S.

Mealybugs may be small, but their impact in greenhouse production can be massive. These sap-sucking pests often sneak in as nearly invisible crawlers and quickly establish persistent infestations—nestling behind leaves, burrowing into root zones, and hiding in plant debris. Once entrenched, they can be notoriously difficult to manage.

At the Turf and Ornamental Entomology Laboratory, we’ve seen firsthand how challenging mealybug outbreaks can be for growers. That’s why PhD students Powlomee Mondal and Peilin Tan, under the guidance of Dr. Zee Ahmed, compiled a comprehensive guide to help greenhouse professionals tackle these pests head-on.

What’s Inside the Strategy

In the article, Managing Mealybugs in the Greenhouse, we outline a science-based, step-by-step approach that includes:

• Accurate species identification to tailor control strategies
• Timed applications based on pest life cycles
• Rotation of systemic and contact insecticides to prevent resistance
• Sanitation protocols, including bench-washing and debris removal
• Efficacy data to guide product selection and application timing

This guide is designed to empower growers with practical, research-backed tactics that reduce pest pressure while preserving plant health and minimizing chemical overuse.

Read the Full Article

Mondal, P., Tan, P. and Ahmed, Z., 2025. How to manage mealybugs in the greenhouse. Greenhouse Management, [online] 24 June. Available at: https://www.greenhousemag.com/article/managing-mealybugs-pest-control-greenhouse/ [Accessed 4 Jul. 2025].

Grower Input Needed:

In addition to the article, Peilin Tan is conducting a brief survey to better understand the current challenges and research needs related to mealybug management in greenhouse systems. The survey consists of nine multiple-choice questions and does not collect any personal information.

We would greatly appreciate your participation:
Take the Survey

Figure 1: Scale insects.

Figure 2: Mealy bug species globally, in the USA, and in greenhouses.

Figure 3: Mealybug species considered greenhouse pests.