Japanese knotweed psyllid

Japanese knotweed psyllid (Aphalara itadori or Psylla itadori) belongs to the family Aphalaridae and is native to Japan. This psyllid has Japanese knotweed (Fallopia japonica) as its host plant and can therefore be used as biological control of this invasive plant. Eggs of the psyllid are found on the underside of the leaves of Japanese knotweed. In warm weather, development from egg to adult psyllid takes about thirty days. Japanese knotweed psyllids hibernate in the bark of conifers. Females lay + 600 eggs on the underside of the leaves of Japanese knotweed. A Japanese knotweed psyllid lives about 60 days. Adult psyllids feed on the cell tissues (meristem) in the leaf, causing it to become deformed. The plant loses leaves, becomes exhausted and growth slows to the point that Japanese knotweed fails to sprout in a subsequent season. Because the Japanese knotweed psyllid only has Japanese knotweed as a host plant, the risk of this psyllid feasting on other plants is basically low.