What do psyllids look like?

Psyllids, along with aphids, scale insects and whiteflies, belong to the Order Hemiptera, suborder Sternorrhyncha.

What do psyllids look like?

Size:

• 1 mm - 40 mm in length.

Body:

• Psyllids, whiteflies and male scale insects are generally widest at the wing attachment (wide shoulders), abdomen tapered or globular.
• Aphids are blob-like.
• Mealybugs look like a dome with segments.
• Lerp insects (immature psyllids) and female scale insects are larvae-like but their waxy coating can come in a wide range of shapes.

Antennae:

• Thread-like, length variable.

Eyes:

• Large and widely separated.
• Often absent in scale insects and other non-moving species.

Mouthparts:

• For piercing and sucking, do not have visible palps (look like a chain of beads).
• Very small tube, thorn-like in appearance and appearing to come from chest.
• A small number of species have reduced mouthparts that maybe difficult to see, or retractable tubular mouthparts that are hidden in the head when not in use.

Wings:

• One or two pairs if present.
• Male scale insects have membranous forewings with only one or two veins, hindwing absent or greatly reduced.
• Both pairs of whitefly wings are membranous, clear or partially see-through with one or two veins.
• Both pairs of psyllid wings are membranous, often covered with white waxy scales.
• At rest, wings are held tent-like over body for all groups.

Limbs:

• Six legs short and stocky.
• Some female scale insects lack legs.

Abdomen tip:

• Cerci (tails) absent.
• Male scale insects may have a single spike or waxy filaments.

Where are psyllids, aphids, scale insects and whiteflies found?

• On the leaves or young stems of plants.
• In ant nests.
• In galls, which they create.

What do psyllids, aphids, scale insects and whiteflies do?

• Some are solitary but most form groups around a common food source.
• When disturbed they jump, run away, remain still or emit an chemical informing others of danger.
• Most lerp and female scale insects are fixed to a plant surface. They hide themselves under waxy or sugary secretions, which harden and form a protective shield. These shields are highly variable in shape, with dome-like to scallop-like shells.
• They are primarily sap feeders.
• Many, especially aphids and mealybugs, are tended by ants, which drink the honeydew they exude.
• Some produce eggs but some such as aphids produce live young. Some do not mate and produce only female offspring.
• They are active during the day or night.

What looks similar?

• Psocids are easily confused with psyllids. Psocids maybe distinguished by their large bulging nose, long antennae, wing veins that form 'S-shaped' lines, long slender legs and they usually run or fly away when disturbed rather than jump.
• Flies can be confused with male scale insects as they both have only one pair of functional wings and another pair that are reduced to haltere-like structures. However, male scale insects have only two or three veins in their wings, the haltere-like structures are not club-like and they often have a tail of waxy filaments. Flies never have this combination of characters.