Peiolegall aphids – Pempighus spp.
Petiole gall aphids (Pemphigus spyrothecae)
Latin Name: Pemphigus spyrothecae
Common Name: poplar spiral gall aphid
- Adult petiole gall aphids are about 1/13 inch (2 mm) long, pale green with a black thorax, and coated in wax.
- They have small, thread-like antennae and don’t have the terminal abdominal tubules known as cornicles that other aphid has.
- Aphids are tiny, soft-bodied insects that induce galling of the leaf stem (petiole).
- Hosts plants: creates round galls on cottonwood, poplar, and aspen petioles; damage primarily aesthetic
Pemphigus spyrothecae is found across Europe, North Africa (Tunisia), western Siberia, Pakistan, and Canada.
Damages caused by Petiole gall aphids:
These aphids may induce some leaf drop and are responsible for the production of the intriguing galls, but they do not harm the plants in any way.
Description about Leaf chewers:
Insect chewing damage to plants can take numerous forms. Foliage or flowers may vanish when certain insects eat them. Occasionally, the plant will appear ragged and, upon closer inspection, will reveal bitten edges or cores. Plants can be cut at the root and topple over, or twigs can be girdled and die as a result. Mining or boring is the process of causing harm to a plant through chewing. Only the upper or lower surfaces are sometimes destroyed, producing a brown, burned look or skeletonization (openings between the veins).
Life History and Habits:
Pemphigus spyrothecae, often known as the poplar spiral gall aphid, is a social insect that appears altruistic. The aphids build galls and protect the colony, sometimes at the cost of their own lives.
Petiole gall aphids have a one-year life cycle in which they switch between two hosts. In the fall, eggs are placed in bark cracks on Populus spp. Trees and the nymphs hatch into asexually reproducing females. Nymphs use tubular, sucking mouthparts to feed on growing leaf petioles. Feeding causes the host plant to generate gall, a swelling growth that envelops the aphid as it develops. Winged adults are created towards the end of the summer and fly back to their winter hosts.