Pepper Mild Mottle

Pepper mild mottle virus (PMMoV) and pepper mottle (PepMoV or PeMV) are not the same diseases. The pepper mild mottle virus is related to the tomato mosaic virus. Unlike pepper mottle, pepper mild mottle does not affect eggplant or tomatoes. It is a peppers-only disease (so far).

Bell peppers infected with pepper mild mottle (UF/IFAS Pest Alert Website/Pamela Roberts) CC BY 2.5

Pepper mild mottle symptoms

Like many other diseases, pepper mild mottle causes stunting and chlorosis, or yellowing of the leaves. It also causes distorted and lumpy fruit, leaf curling, and streaking. These symptoms will vary depending on the species and cultivar.

Pepper leaves infected with pepper mild mottle on the left (Yubing Jiao, et al) CC BY 4.0

Pepper mild mottle management

The virus that causes pepper mild mottle occurs around the world. It is the most abundant RNA virus found, I beg your pardon, in human feces. It ends up that we are the Number One carriers of this disease. Just as livestock manure can carry many pathogens, such as E. coli, our waste can, too. This virus also moves around on our clothing, tools, and skin. There is some suspicion that this virus can also cause disease in people, but more research is needed. Whether it hurts us or not, it can devastate your pepper plants.

This pathogen thrives in heat and humidity, making it a common problem in greenhouse environments. The viruses can enter plants through wounds and other damaged areas. This disease is highly contagious in the pepper world. And it remains viable on tools, containers, structures, and plant debris for a long time.

Remove any plants infected with pepper mild mottle and throw them in the trash. Do not add them to the compost pile or burn them. These viruses are so rugged that they can travel on smoke! And wash your hands.

Commercial growers used to apply methyl bromide as a pre-plant treatment. Most countries have banned that nasty chemical. One Japanese study demonstrated that soil that contains a lot of humus is less likely to harbor the pepper mottle virus, so keep mulching and composting. Crop rotation is a good idea, too.

The best way to prevent this problem is to use certified disease-free seeds and seedlings.