INTERESTING INSECTS

By N A Martin (2017, revised 2019)

Lancewood psyllid, Lancewood jumping plant louse

Powellia panacis (Maskell, 1890)

This endemic psyllid lives in the North and South Islands of New Zealand. It occurs in city gardens and parks as well as native ecosystems on its host plants, lancewood, Pseudopanax crassifolius, and closely related, Pseudopanax species.

Conservation status: Widespread, not threatened, a minor pest in gardens.

In Auckland, adults and juveniles may be found all year. In colder areas the insect probably overwinters as adults, probably females that were mated the previous autumn. Adults each have three pairs of legs and two pairs of transparent wings that are held partly covering their abdomens. The body is green. The head has a pair of antennae, a pair of compound eyes and a ventral rostrum that holds the stylets used for feeding. The male has a complex apparatus at the tip of the abdomen that is used for grasping the female during mating. While mating the male sits alongside the female, facing in the same direction, and the end of the abdomen curls under the female and the tip of her abdomen. The tip of the female’s abdomen is slender and houses a narrow blade-like ovipositor that assists with egg laying.

Eggs

Females lay eggs on the surface of leaves. They are laid on the underside of older leaves amongst a psyllid colony or on young expanding leaves. Eggs are shining, smooth and tear drop-shaped. The egg base has a short stalk that may be inserted into the plant. The eggs are a pale cream. A few days before hatching red eyespots are present. Eggs are about 0.35 mm long.

Scale-like nymphs

Nymphs hatch from the eggs. First instar (stage) nymphs are small, pale brown, flat and oval shaped. They have three pairs of legs and sucking mouthparts. They settle on the upper side of young expanding leaves or on the underside of older leaves. There are five nymphal stages, and each is called an instar. Nymphs go from one stage to the next by moulting (changing their skin). During moulting, the skin on the dorsal side splits and the next stage pulls itself out of the old skin which in many Lancewood psyllid nymphs remains attached on the tip of the abdomen. Older nymphs may have two or three moulted skins attached. Adults emerge from fifth instar nymphs.

As the insects progress through the nymphal stages their colour and shape changes. The second, third and fourth instar nymphs are usually pale while the fifth instar has brown marking that are almost black centrally. Some early instars also have dark markings. The older instars have progressively larger wing buds.

The length of time needed for egg and nymphal development depends on the temperature.

Walking jumping and flying

Adults and all nymphal stages possess three pairs of legs that are used for walking. When the adults are at rest and walking the last pair of legs are held under the body (see photo of underside of an adult male). These hind legs are used make the adult jump if it is disturbed. And hence a common name for psyllids, jumping plant lice. The adults also possess wings and can fly, which aids dispersal and location of new host plants.

Feeding and honeydew

Like other Hemiptera, the lancewood psyllid has sucking mouthparts. The long stylets, which are specially shaped rods, are held in the rostrum. When it wishes to feed, the psyllid moves the tip of the rostrum to the surface of a leaf or stem. The stylets are then gradually pushed into the plant. The stylets form two tubes, one through which saliva is injected into the plant and a second through which plant juices are sucked up into the insect. The lancewood psyllid inserts the stylets into the phloem (the plant vessels for transmitting sap from the leaves to other parts of the plant). The sap has a high volume of water and sugars, more than the insect needs. The psyllid excretes the excess water and sugar, which is called honeydew.

Adult female Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5L]

Adult male Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae), note the bulbous tip of the abdomen. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5K]

Dorsal (top) of adult female Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae), note the slender tip of the abdomen. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5H]

Dorsal (top) of adult male Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae), note the bulbous tip of the abdomen. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5I]

Adult female Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae), note the slender tip of the abdomen. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5J]

Underside of adult female Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae), note the slender tip of the abdomen. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5G]

Eggs of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) on underside of leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H58]

Two first stage (instar) nymphs of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) on underside of leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5D]

Second and third stage (instar) nymphs of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) on underside of leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5C]

Third and fourth stage (instar) nymphs of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) on underside of leaf, note the moulted skins of earlier instars attached to their abdomen. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5F]

Second stage (instar) nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) on underside of leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5Y]

Second stage (instar) nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) on underside of leaf with moulted skin. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5Z]

Nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) in pit on upper side of leaf of Pseudopanax lessonii. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5X]

Nymphs of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) in pit on underside of leaf of Pseudopanax lessonii; note the moulted skin with skins of earlier instars attached. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H60]

Fifth stage (instar) nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) on underside of leaf, and moulted skin with skins of earlier instars attached. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5A]

Fifth stage (instar) nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae): note the moulted skins of earlier instars attached to its abdomen. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H59]

There are several kinds of psyllids in New Zealand, the adults of which look very similar to the lancewood psyllid and can only be distinguished through microscopic examination. However, the Lancewood psyllid, Trioza panacis, is the only species that breeds on Lancewood, (Pseudopanax crassifolius), Fierce lancewood (Pseudopanax ferox) and Coastal five finger (Pseudopanax lessonii).

Aphids could be confused with Lancewood psyllids on Pseudopanax lessonii. Winged aphids are similar in size to adult psyllids, but have globular bodies and the round ended wings are held above their bodies. Psyllids are more like tiny cicadas, slender with point ended the wings that cover the body when they are at rest. Furthermore, the abdomen of the adult psyllid often twitches from side to side.

Juvenile lancewood psyllids are flat and scale like, unlike globular long legged aphids. The presence of moulted skins on nymphs is a distinctive feature.

The presence of pits in host plant leaves and associated chlorotic (yellow or red) areas on leaves is an indication of the presence of Lancewood psyllid.

Adult female Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5L]

An aphid holding its wings above its body; melon aphid (Aphis gossypii Glover, 1877 (Hemiptera: Aphididae). Creator: DSIR photographers. © Plant & Food Research. [Image: 3HB]

Eggs and small nymphs of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) on underside of leaf. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6F]

Two second stage (instar) nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) on underside of leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5B]

Underside of lancewood, Pseudopanax ferox (Araliaceae) leaf with nymphs of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2H57]

Fifth stage (instar) nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae): note the moulted skins of earlier instars attached to its abdomen. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H59]

Underside of lancewood, Pseudopanax crassifolius (Araliaceae) leaf with pit galls induced by lancewood psyllids, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6R]

Lancewood, Pseudopanax crassifolius (Araliaceae) leaves with pit galls and chlorotic (yellow) areas induced by lancewood psyllids, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H5Q]

Chlorotic (yellow) areas on leaves of Pseudopanax lessonii (Araliaceae) cuased by feedong of Lancewood psyllids, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6U]

Chlorotic (red and yellow) areas on leaves of Pseudopanax lessonii (Araliaceae) caused by feeding of Lancewood psyllids, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H54]

Pathogens

Two fungal pathogens of the Lancewood psyllid have been found. A white fluffy fungus on nymphs is called Torrubiella confragosa Mains (Clavicipitaceae) (previously called Verticillium lecanii) and the fungus with spiky growths on an adult and nymph is Hirsutella saussurei (Cooke) Speare (Ophiocordycipitaceae).

Predators

Birds probably feed on the psyllid, but there are no specific reports. Spiders and several species of lacewings, ladybirds and mirid bugs are likely to pry upon adult and juvenile lancewood psyllids.

Parasitoids

At least three species of parasitoid wasp (Hymenoptera) have been reared from Lancewood psyllid nymphs. One species is Tamarixia sp. A (Eulophidae), a parasitoid of several native psyllids. The adult female has a pale area on the top (dorsal) abdomen. This parasitoid lay an egg on the underside of the nymph, the wasp larva lives under the psyllid and feeds from the outside. When the larva is full grown, the wasp larva pupates under the psyllid nymph. The adult wasp, after emergence from the pupa, chews an exit hole in the top, dorsal, side of the dead nymph. Another the adult female of another apparent ectoparasitoid is all black on top, has dark hind legs and the middle pair of legs have a prominent tibial ‘spine’.

Endoparasitoids (Encyrtidae) lay an egg in the nymph and the wasp larva develops in the psyllid nymphs body. When it is fully grown the larva pupates within the nymph. Again the adult wasp chews an exit hole in the top of the nymph.

A sign that parasitoids have killed lancewood psyllid nymphs is a round exit hole made by the adult parasitoid, though this does not provide information about the kind of parasitoid.

White fluffy fungal pathogen, Torrubiella confragosa Mains (Clavicipitaceae) (previously called Verticillium lecanii), growing on nymphs of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5R]

Nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) with developing fruiting bodies of a fungal pathogen, Hirsutella saussurei (Cooke) Speare (Ophiocordycipitaceae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5S]

Adult Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) with fruiting bodies of a fungal pathogen, Hirsutella saussurei (Cooke) Speare (Ophiocordycipitaceae). Other nymphs with exit hole of parasitoid. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5T]

Fifth stage (instar) nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) with exit hole of an adult parasitoid. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5M]

Fourth stage (instar) nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) with exit hole of an adult parasitoid. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5N]

Underside of two fifth stage (instar) nymphs of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) that have been parasitised by wasps; the upper nymph is parasitised by an endoparasitoid and the lower nymph is parasitised by an ectoparasitoid, note the black wasp pupa. Creator: Tim Holmes. © Plant & Food Research. [Image: 2H62]

Adult wasp ectoparasitoid that emerged from nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2H61]

Brown pupa of wasp parasitoid from under nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H69]

Brown pupa of wasp parasitoid from under nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6B]

Adult female wasp parasitoid that emerged from nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H63]

Adult male wasp parasitoid that emerged from nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae), note the branched antennae. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H64]

Underside of adult female wasp parasitoid that emerged from nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H66]

Underside of adult male wasp parasitoid that emerged from nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae), note the branched antennae. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H65]

Ectoparasitic (living outside) larva of wasp parasitoid from under nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H67]

White pupa of wasp parasitoid from under nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H68]

White pupa of wasp parasitoid from under nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6C]

Wasp parasitoid exit hole in nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6D]

Underside of nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) with parasitoid in its body. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6E]

Pupa of wasp parasitoid under nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6G]

Adult female wasp parasitoid and exit hole in nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6I]

Adult female wasp parasitoid and exit hole in nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6H]

Adult female wasp parasitoid from a nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6K]

Underside of an adult female wasp parasitoid from a nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6J]

Nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae) that appears to be parasitised by a wasp living in its body. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6L]

Wasp parasitoid exit hole in nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6M]

Dead adult female wasp parasitoid from a nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6P]

Dead adult female wasp parasitoid from a nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae), note the dark area on the wing. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6N]

The lancewood psyllid, Trioza panacis, breeds on leaves of three species of Pseudopanax, Lancewood, Fierce lancewood and Coastal five finger (Araliaceae).

Feeding and plant damage

When the psyllid nymph settles and feeds on a young expanding leaf, a pit gall is formed. This happens when the nymph settles on the upper or lower side of the leaf. Very young leaves may also develop areas of chlorotic (yellow or red) tissue as a result of psyllid feeding. In a heavy infestation a leaf can become badly distorted and in lancewood, the edge of the leaf may roll over. The presence of dimples and yellow or red areas on leaves makes it easy to recognise plants that have been infested by this insect.

Lancewood, Pseudopanax crassifolius (Araliaceae) leaves with pit galls induced by lancewood psyllids, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6Q]

Coastal five finger Pseudopanax lessonii (Araliaceae) leaves with pit galls induced by Lancewood psyllids, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6T]

Chlorotic (yellow) areas on leaves of Coastal five finger, Pseudopanax lessonii (Araliaceae) caused by feeding of Lancewood psyllids, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H6S]

Chlorotic (red and yellow) areas on leaves of Coastal five finger, Pseudopanax lessonii (Araliaceae) caused by feeding of Lancewood psyllids, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H55]

Leaf of Coastal five finger, Pseudopanax lessonii (Araliaceae) with chlorotic area and pit with a nymph of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2H5W]

Underside of lancewood, Pseudopanax ferox (Araliaceae) leaf with nymphs of Lancewood psyllid, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H56]

Lancewood, Pseudopanax crassifolius (Araliaceae) leaves with chlorotic (yellow areas and leaf edge roll caused by feeding of Lancewood psyllids, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H52]

Lancewood, Pseudopanax crassifolius (Araliaceae) leaves with chlorotic (yellow areas and leaf edge roll caused by feeding of Lancewood psyllids, Trioza panacis (Hemiptera: Triozidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2H53]

Nymphs of Lancewood psyllids, Trioza panacis (Hemiptera: Triozidae) on the underside of a leaf of Lancewood, Pseudopanax crassifolius (Araliaceae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2SBK]

Nymphs of Lancewood psyllids, Trioza panacis (Hemiptera: Triozidae) on the underside of a leaf of Lancewood, Pseudopanax crassifolius (Araliaceae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2SBL]

Juvenile leaves of Lancewood, Pseudopanax crassifolius (Araliaceae) galls induced by feeding of Lancewood psyllids, Trioza panacis (Hemiptera: Triozidae): note that the nymph had been feeding on the upper side of the leaf (left) in the cavity in the gall. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2SBM]

Plant-SyNZ: Invertebrate herbivore-host plant association database. plant-synz.landcareresearch.co.nz/

Sommerfield KG 1984. Greenhouse and ornamental pests. In: Scott RR ed. New Zealand pest and beneficial insects. Canterbury, New Zealand, Lincoln University College of Agriculture. Pp. 65-92.

Tuthill LD 1952. On the Psyllidae of New Zealand (Homoptera). Pacific Science 6(2): 18-125.

Pam Dale for psyllid identifications and information about the psyllid.

Peter Workman for information about the psyllid, especially its natural enemies, and photographs.

The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research) for permission to use photographs.

1 October 2019, NA Martin. Recognition: changed ‘continually twitches’ to ‘often twiches’.

1 August 2018, NA Martin. Photos added of nymphs and galls on lancewood.