Leaf-spotting bug
Adult leaf-spotting bug on a eucalypt leaf
© Queensland Government
Leaf-spotting bug symptoms on Dunn’s white gum leaves
© FWPA
Leaf-spotting bugs extract nutrients from leaves and inject enzymes into leaves when feeding, creating dead patches. They can cause leaf shedding, and large infestations can lead to tree death.
Scientific name
Rayieria species
Other names
- Mirid bugs
- Acacia spotting bugs
Description
- Leaf-spotting bugs are thin, elongate, medium-sized bugs (8–10mm long).
- Their colouring varies across different species and can be:
- orange to red in the thorax with black and white abdomen and wing covers
- mainly white or yellow to pale brown, sometimes with a reddish tinge
- greenish, reddish or brown to black with white or pink markings.
- Their antennae are as long as or longer than their body.
Distribution
- Throughout Queensland
Hosts
- Acacia species
- Plants from the Myrtaceae family, including:
- Dunn’s white gum (Eucalyptus dunnii)
- broad-leaved paperbark (Melaleuca quinquenervia)
Damage
- Both adults and nymphs are sap suckers, extracting nutrition from leaves. Adults are mostly present in the lower third of the canopy.
- They inject enzymes into the leaf while feeding, causing dead patches to form on the upper leaf surface. Dead patches are generally square to rectangular.
- Severely affected leaves have reduced photosynthetic capacity and may shed prematurely.
- Large infestations can cause tree death.
Biology
- Females lay eggs in the young stems of plants in groups of 1 to 7, and cover them with a waxy substance.
- There are 5 nymphal instars, each lasting about 3 days.
- Adults usually live for 1–3 months.
- Nymphs and adults feed by inserting their stylets into leaf tissue. They inject enzymes into the leaf to help with digestion of leaf cells and their contents.
- Adults are swift and active flyers and are mostly present in the lower third of canopy.
Control
- Predators of leaf-spotting bugs have not been identified but are likely to include various birds and other insects.
- Additional control is not usually necessary.
Resources and research
- Carnegie, AJ, Lawson, SA, Smith, TE, Pegg, GS, Stone, C, McDonald, JM, 2008, Healthy hardwoods: a field guide to pests, diseases and nutritional disorders in subtropical hardwoods, Forest & Wood Products Australia, Victoria.
- Namyatova, AA, Cassis, G, 2013, Systematics, phylogeny and host associations of the Australian endemic monaloniine genus Rayieria Odhiambo (Insecta : Heteroptera : Miridae : Bryocorinae) , Invertebrate Systematics, 27:689–726.