Authors：Ya-Ling Lin, Te-Pin Chang, Gene-Sheng Tung

Year：2014

Key words：eucalyptus, gall, Leptocybe invasa, susceptibility tests, host preferences

Eucalyptus trees are the collective name of the genus Eucalyptus which is in the family
Myrtaceae. These are globally well-known species with fast-growing characteristics and
economic value. Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae), the gall
wasp of eucalyptus trees, originated in Australia. In 2000, the gall wasp was discovered
in Israel. It causes damage to young eucalyptus branches, petioles and veins. It can affect
the growth of plants and cause serious infections and even death. The gall quantity,
density, and plants damaged varied among various host species. In this study, we found
that 10 eucalyptus species were affected by L. invasa, but with different extents of
infection: E. amplifolia, E. camaldulensis, E. citriodora, E. dunii, E. grandis, E.
maculata, E. propinqua, E. robusta, E. saligna, and E. tereticornis. Among them, E.
camaldulensis, E. grandis, and E. saligna were the 3 most vulnerable ones. Because of
variable degrees of resistance of these species of eucalyptus, we carried out susceptibility
tests on 7 different known strains of eucalyptus using Fisher’s least significant difference
(LSD) test. We found that most of hybrid strains from E. grandis and E. camaldulensis had
higher infection rates by L. invasa than did the other strains. On the contrary, hybrids from
strains GUT5 and L151 had lower infection rates. The results can help us choose suitable
strains to protect against L. invasa.