Pest Of The Month: Pepper Mild Mottle Virus

Pepper mild mottle virus (PMMoV) can be found virtually anywhere peppers are grown because the virus is generally introduced with the pepper seed. The virus moves long distances on the seed and moves short distances via plant-to-plant contact. Handling of plants by contaminated implements and workers aids in the spread of the virus. PMMoV enters the plant through very tiny wounds.

As pepper is the primary host, symptoms from infection due to contaminated seed can show up fairly soon after planting. Typically fifth or sixth true leaf plants will be noticeably stunted compared to non-infected plants. Infected plants also show leaf mottling and puckering.

PMMoV is in the tobacco mosaic virus family, and these viruses are known for being very easily spread and extremely difficult to kill. It is also important to be sure the virus is accurately identified. For example, pepper mottle virus, which has symptoms similar to PMMoV, is transmitted by aphids and not by contaminated tools or people.

Control Measures

The best way to combat the virus is to use virus-free seeds or transplants grown from virus-free seeds. There is no way to “cure” pepper plants once they are infected with the virus so growers need to focus on avoiding getting the virus in the first place. Rouging infected plants — if done carefully to avoid contaminating non-infected plants — may help.

Diseased plants can cause additional infection until they are completely broken down. Tillage, increased irrigation, and high temperatures help with the breakdown of plant material in the soil. Crop rotation is encouraged as infected plant material in the soil can serve as a source of inoculum for the next pepper crop.