Beet Western Yellows

Bright yellow, red, or purple leaves may indicate beet western yellows, though this plant disease is not limited to beets or the west.

Beet western yellows virus is responsible for significant losses in many global crops. Unfortunately, free-to-use photos are not as readily available. You can search online to see what this disease looks like.

Beet western yellows host plants

This disease occurs on over 250 plant species, including beets, broccoli, cabbage, canola, cauliflower, chickpeas, endive, escarole, fava beans, lentils,  lettuce, mustard, peas, peppers, radish, 
spinach, sunflowers, tomatoes, turnips, and oilseed rape. Oilseed rape is a member of the cabbage family grown for its oily seeds and as food for livestock.

It can also occur on annual phlox, bee’s friend, false flax, and lupine. Weeds that harbor beet western yellows include chickweed, common groundsel, prickly lettuce, little mallow, shepherd’s purse, sowthistles, and pennycress. [Even though it is a weed, pennycress is commonly used to salvage toxic soil through phytoremediation.]

Spinach plants infected with beet western yellows (Howard F. Schwartz, CSU, Bugwood.org) CC BY 3.0 US

Beet western yellows virus symptoms

Symptoms of beet western yellows infection vary depending on the affected species and the virus strain, making diagnosis tricky.

Most plants infected with BWYV don’t show any signs at first. Then red, blue, purple, or black discolorations that start at the tips and edges of leaves appear. Eventually, the entire leaf turns bright yellow or orange. Petioles and veins remain green or may be pale. Infected leaves feel thick and brittle, and they may curl upward. Stunting is common, and leaf crinkling may occur. These symptoms look similar to iron or nitrogen deficiencies or chemical overspray.

Beet western yellows virus management

Aphids spread beet western yellows. Green peach and wheat aphids are the biggest culprits, though other aphid species are involved. So, the best way to prevent and manage beet western yellows is to control aphids and eliminate rouge host plants. 

Also known as turnip yellows and turnip mild yellows, some cultivars are resistant to this disease. Look for the letters TuYV, BWYV, and TuMYV on plant labels. Buying resistant plants makes your job a lot easier.

Avoid planting too early in a season, as this can make plants more vulnerable to beet western yellows. Toss infected plants in the trash.

There are no chemical controls for viruses (yet).