The bugs that eat parsley include aphids, carrot weevils, clickbeetles, several species of moths and worms, and two spotted spider mites.
These tiny, white, soft-bodied insects attack parsley with their piercing-sucking mouthparts, which they use to feed on plant juices. They deplete the plant of nutrients while injecting toxins that can cause abnormal plant growth.
Adult carrot weevils puncture a hole in the parsley's petioles and lay eggs. The newly hatched larvae feed on parsley roots killing the plant if it is, severely injuring it if is more established.
This brown, black, or gray beetle is about ½"-1" long produce larvae, which feed on the seeds and roots of plants beneath the soil surface hollowing the stems. Young plants begin to wilt and quickly die.
Several species of moths lay eggs that feed destructively on plants including parsley. They include the beat armyworm, cabbage looper, and the granulate and black cutworm. The female moth lays eggs on the underside of plant leaves, which develop into larva that feed on the leaves and stems of a plant. This feeding cuts off plant stems as well as kills developing petioles.
Two spotted Spider mites
Though the tiny spider mite is only 1/50" long, it can severely damage your parsley plants. Spider mites pierce plants with their sucking mouthparts extracting the juices causing graying and yellowing of the leaves.