Insects on a Primrose

Remove beet armyworms from your primroses by hand. The beet armyworm is actually a caterpillar that eats both the leaves and flowers. They are green or black with yellow stripes. If you see any of these critters on your primroses, simply pick them off the flower and remove them from your garden.

Introduce parasitic wasps or tachnid flies to kill off large infestations of beet armyworms.

Apply insecticides to get rid of night creatures such as the black vine weevil. The black vine weevil eats primroses and other plant species in the night hours, so hand-removing them would be difficult. Introduce beauveria bassiana, a fungus that kills the weevils, or apply a chemical insecticide containing the active ingredient azadirachtin.

Search for yellowing leaves, a sign of whitefly damage. Whiteflies suck the liquid from the primrose and drop honeydew on the primroses, which grows a fungus that destroys the plant. Apply a chemical pesticide that contains malathion to get rid of whiteflies.

Search for webbing under the leaves. Webbing is usually an indicator of spider mites, which eat and live on the primroses. Spray insecticidal soap on your primroses to get rid of them.