Dealing with Whiteflies in a Hydroponic System

What Whiteflies Do

Whiteflies are tiny sap-sucking insects that cluster on the undersides of leaves. They extract plant fluids, causing yellowing, wilting, and stunted growth, and excrete sticky honeydew that promotes sooty mold and can spread plant viruses. [1]

Latin Name

Bemisia tabaci (silverleaf whitefly) and Trialeurodes vaporariorum (greenhouse whitefly). [1]

Identification

Adults: 1-2 mm, moth-like, white, powdery wings
Nymphs: oval, flattened, scale-like, on leaf undersides [3]
When disturbed, adults fly up in clouds
Leaves exhibit honeydew deposits and sooty mold

Alternative Names

Silverleaf whitefly
Greenhouse whitefly
Cotton whitefly
Tomato whitefly

Varieties (Common Species)

Bemisia tabaci (Silverleaf whitefly) [1]
Trialeurodes vaporariorum (Greenhouse whitefly) [1]
Bemisia argentifolii (Sweet potato whitefly) [4]

Climates Where They Thrive

Warm, humid conditions (20-30 °C, RH ≥ 60 %) [3]
Poorly ventilated, stagnant airspaces
Populations decline in temperatures below 15 °C or very dry (< 40 % RH) environments [3]

Companion Planting as Deterrents

Cultivar	Hydroponic Methods	Effectiveness
Chrysanthemum (Tanacetum cinerariifolium)	All (DWC, NFT, Ebb & Flow, Drip)	High-pyrethrins repel adults [2]
Marigold (Tagetes spp.)	All methods	Moderate-thiophenes deter feeding [2]
Basil (Ocimum basilicum)	NFT, DWC, Drip	Moderate-aromatic oils mask host cues [5]
Mint (Mentha spp.)	Wick, Kratky, Drip	Moderate-strong scent disrupts landing [5]
Cilantro (Coriandrum sativum)	All methods	Low-attracts beneficial predators [6]

Natural Predators

Encarsia formosa (parasitic wasp) [4]
Delphastus catalinae (predatory beetle) [4]
Macrolophus pygmaeus (mirid bug) [6]
Ladybird beetles (Coccinellidae) [6]

Remedies

Treatment	Hold Period	Natural?	Effectiveness
Insecticidal soap spray	1 day	Yes	Moderate-direct contact kill [2]
Neem oil emulsion	3 days	Yes	Moderate-repellent & growth disruptor [2]
Pyrethrin spray	7 days	No	High-rapid knockdown [3]
Yellow sticky traps	0 days	Yes	Low-monitoring & some adult capture [1]

Other Remedies

Reflective mulch: Aluminum film to confuse landing adults [5]
UV LED traps: Low-intensity UV light to attract and trap adults [3]
Essential oil diffusion: Disperse lavender or lemongrass vapor [6]
Vacuum suction: Gently remove adults with a handheld vacuum [6]

Tips and Tricks

Inspect undersides of leaves daily under bright light
Maintain humidity around 60 % and good airflow to discourage colonies [3]
Quarantine new plants under fine mesh for 7-10 days
Rotate treatments weekly to prevent resistance
Sanitize reservoirs and trays between crop cycles

Common Hosts

Tomatoes, Peppers, Cucumbers [1]
Leafy greens (lettuce, spinach) [1]
Herbs (basil, mint, cilantro) [5]
Strawberries, Ornamentals [3]

Citations

[1] Whitefly - Wikipedia - https://en.wikipedia.org/wiki/Whitefly
[2] How to Get Rid of Whiteflies in Hydroponics - Eden Green Technology - https://www.edengreen.com/blog-collection/whiteflies-hydroponics
[3] Whitefly Pest Notes - UC IPM - https://ipm.ucanr.edu/PMG/PESTNOTES/pn7403.html
[4] Biological Control of Whiteflies in Protected Culture - UF IFAS EDIS - https://edis.ifas.ufl.edu/publication/IN163
[5] Companion Planting - Wikipedia - https://en.wikipedia.org/wiki/Companion_planting
[6] Natural Enemies of Whiteflies - CABI Invasive Species Compendium