In Case You Missed It: Two-Spot Cotton Leafhopper – a New Pest of Hibiscus.

Just when we think we have Thrips parvispinus under control, a new pest is threatening tropical ornamentals. The two-spot cotton leafhopper (Amrasca biguttula) is mainly a pest of – you guessed it, COTTON – but also attacks hibiscus. Growers in Ontario should be aware of this pest if importing hibiscus cuttings from the Southern U.S., where this pest has currently invaded.

There’s been lots of good information shared on this pest recently. Read on for a summary relevant to ornamental growers, including what to look for, effective pesticides and what actions you should take NOW.

The Pest:

A pest alert was first put out by Florida Department of Agriculture in 2023. Since then, Two-spot cotton leafhopper (or TSCL from now on, because I’m not typing that out forever) was first found in the mainland U.S. in the summer of 2025, according to a publication by several researchers in that region. TSCL originates from the Indian subcontinent, and is known to feed on cotton, okra, and eggplant. The only recorded ornamentals this pest feeds on are hibiscus and sunflower, but this host list may expand as we learn more about how this pest adapts to North American crops.

Regulatory Status:

Two-spot cotton leafhopper is currently a regulated pest in the Southern U.S.. Nurseries found with the leafhopper are placed under a “stop sale and hold order”. As of mid November, 43 nurseries were quarantined in Florida alone.

Given that it’s a regulated pest, any presence of the leafhopper on a shipment of plants returning to the U.S. from Canada could result in the shipment being held or turned around.

Note that this pest is NOT known to be able to survive at cold temperatures, so it is unlikely to establish outside in Canada, or in the Northern U.S.

Damage:

Damage from any leafhopper results in what is known as “hopper burn”. The adults and nymphs of TSCL feed on the contents of plant cells on the undersides of leaves, turning the leaves chlorotic, then red, then eventually brown. On hibiscus, leaf curling is also a symptom of feeding.

Treating Cutting Material Upon Receipt:

One strategy you can implement NOW to mitigate your risk from this pest is to dip your cuttings in reduced-risk pesticides.

Although we don’t have data for this specific pest yet, dips have been shown to reduce levels of all sorts of insects that come in on hibiscus, including thrips, whitefly and spider mite. Part of this efficacy comes from simply washing the pests off the cuttings. The University of Florida will be working on dips specific for TSCL, but for now, it’s probably wise to dip your cuttings with products we know to be effective on another pest of hibiscus coming from Florida and Texas: Thrips parvipsinus.

In a previous post, I talked about some products that are effective for Parvispinus as cutting dips. (For more current information on dip options for Thrips parvispinus and their efficacy, check out the latest American Floral Endowment (AFE) webinar by Dr. Rose Buitenhuis). The Vineland Research and Innovation Centre also expanded tests of cutting dips to other tropicals affected by T. parvispinus, including hibiscus, to check for phytotoxicity of the dip solutions on different plant species.

It turns out hibiscus are generally are more sensitive to dips than mandevilla or anthurium. Products that should be AVOIDED on hibiscus include Lalguard M52 OD and Suffoil X (both oil-containing products), along with Bioceres WP. Generally, EC formulations were fine, including BotaniGard ES and Bioceres ES.

Chemical Control:

Pesticide trials for TSCL have been done by the University of Florida, Clemson, and the University of Georgia. Click on the university name to go straight to their results (go to slide 22 of the UofF presentation for the information from Georgia).

To make things easier, I’ve summarized the effective pesticides in a table. Note that some of the data is lab-based, so efficacy may be reduced on whole-plants. Since this is an ornamental blog, I’ve only included those chemicals registered on ornamentals. Always check to see if these products are registered on YOUR crop group in YOUR state or province.

Multiple sprays will likely be needed to control this pest, as the eggs are protected within the leaf tissue (similar to thrips). This means 2 sprays, 5-10 days apart, will be needed to hit the whole population. If further sprays are needed within the pest’s generation time (around 30 days at warmer temperaturs), then make sure to switch to a new chemical class to avoid resistance.

Table 1. Relative efficacy of pesticides registered on ornamentals for two-spot cotton leafhopper. Higher stars indicate better efficacy in tests of both direct contact and pesticide residue tests and/or field tests. Four starts indicates 80% control or better, two stars indicates at least 50% control – may also indicate variable results across studies. Anything lower than 50% control is not included.

CDN Trade Name	U.S. Trade Name	Active	IRAC Group	Efficacy Rating
Beleaf	Aria	flonicamid	29	****
Talus	Talus	buprofezin	16	****
N/A	Hachi-Hachi	tolfenpyrad	21A	****
N/A	Safari	dinotefuran	4A	****
Altus	Altus	flupyradifurone	4D	****
(sub in Kopa?)	M-pede	insecticidal soap	UC	****
Intercept	Merit	imidacloprid	4A	***
Orthene	Acephate	acephate	1B	***
N/A	Talstar	bifenthrin	3A	**
Ventigra	Ventigra	afidopyropen	9D	**
Ference	Mainspring	cyantroniliprole	28	**
Rimon	Pedestal	novaluron	15	**
Suffoil X	Suffoil	mineral oil	UC	**

The good news here is that several chemicals seem to be effective for this pest, and some have been validated in field trials (on cotton). The bad news is a lot of these could potentially disrupt biocontrol programs for other pests in hibiscus, including whitefly, thrips and spider mites – especially those chemicals in IRAC classes 1 and 4.

If you are doing biocontrol for other pests of hibiscus, and encounter TSCL, your best bets for compatibility with natural enemies are applications of Beleaf, Ventigra, Suffoil, Rimon and even Talus, as it has a low residual (1 week).

Biological Control:

University of Florida researchers are also looking into the possibility of biological control. Both green lacewings and Orius will prey on the leaf hoppers, but this was in lab trials. It remains to be seen if these predators can effectively control hoppers on whole plants. (Remember, they hop!)

More Resources:

There’s was an excellent webinar on this pest from the Horticultural Research Institute recently. You can access it using this link: Understanding and Managing the Two-Spotted Cotton Leafhopper

For updates on this pest, you can follow the University of Florida’s Tropical Research and Education Centre’s webpage.