Biology of the Eucalyptus leaf beetle Paropsisterna selmani (Chrysomelidae: Paropsini): a new pest of Eucalyptus species (Myrtaceae) in Ireland
- The biology of the Eucalyptus leaf beetle Paropsisterna selmani (de Little) (Chrysomelidae: Paropsini) was assessed in the field and under laboratory conditions. The invasive species, most probably from Tasmania, severely defoliates the new flush foliage of several Eucalyptus species in Ireland.
- The adult beetles and larvae both fed on the foliage and caused typical broom-top damage to trees. Adult beetles over-wintered in the soil and emerged in April and laid egg batches of approximately seven eggs on the leaves. Teneral adults were most noticeable in late June and July.
- In bioassays, the life cycle took approximately 26 days to complete at 20 °C, and survival rates were approximately 67% when fed on E. parvula. Teneral adults took 13.3 days to initiate egg-laying. Leaf consumption was highest in female larvae, and adult beetles consumed a leaf area of approximately 102 mm2/day.
- A mean daily egg-laying rate of 11.4 eggs/female was recorded over a period of 130 days. This egg-laying rate is comparable to other leaf beetles attaining pest status in other Eucalyptus-growing regions.
- The biology of Pt. selmani suggests that this will be a significant pest of Eucalyptus species grown for cut-foliage and forestry in Ireland. It also poses a potential threat to eucalypt-growing regions in the U.K. and mainland Europe.