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.
