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Summary
The sap-sucking psyllid Creiis lituratus has become a significant pest of young Eucalyptus dunnii plantations in north-eastern New South Wales (NSW) and south-eastern Queensland. Previously recorded from native forests and amenity trees, but not as a significant pest or from E. dunnii, it has recently (1998–2004) caused severe damage in plantations 1–5 y old. This paper reports observations on C. lituratus from routine and specific forest health surveys, as well as preliminary results from a detailed study on the behaviour and pest management of the insect, with the objective of highlighting the presence of this new insect pest in commercial plantations. Damage symptoms associated with C. lituratus are chlorosis, reddening and necrosis of leaves. Moderately—to severely-affected trees take on a purple-brown colour and damaged (necrotic) leaves are often retained on trees until re-foliation occurs over summer. Severely-affected trees, where >75% of the tree has been damaged, may experience severe defoliation, tip dieback and the sprouting of epicormic shoots the following growing season. Damage can occur on both immature and mature (fully expanded) juvenile, intermediate and adult foliage. Populations are most active over autumn—winter when nymphs can occur in large numbers, virtually covering the entire (abaxial) leaf surface. Creiis lituratus was first observed causing severe damage in several E. dunnii plantations south of Bonalbo in north-eastern NSW in 1998. In 1999 and 2000, severe crown damage was observed in more plantations around Bonalbo, as well as in plantations around Casino. In 2003 C. lituratus caused severe crown damage in up to 25 E. dunnii plantations within 100 km of Bonalbo, with almost 500 ha moderately to severely affected. About 450 ha were sprayed with insecticide (dimethoate). Damage from C. lituratus was more localised in 2004, with less than 50 ha significantly affected; most of this was sprayed with insecticide. Creiis lituratus has been observed in E. dunnii and E. grandis plantations from Bulahdelah to south-eastern Queensland, but significant damage has occurred only in E. dunnii plantations from Grafton north. The occurrence of C. lituratus in plantations south of Grafton is sporadic.
