Susceptibility of 18 eucalypt species to the gall wasp Leptocybe invasa in the nursery and young plantations in Vietnam

The gall wasp, Leptocybe invasa, is a devastating pest of eucalypt plantations, woodlots, and urban trees in the Middle East, the Mediterranean basin, Africa, India, South-East Asia, and China. It was first observed in Israel in 2000 and has since spread rapidly south and east. It reached southern Vietnam in 2002 and has since moved northward devastating nurseries and young plantations. Eighteen species of eucalypts were selected for a sentinel trial in northern Vietnam to determine their susceptibility to pathogens in the region. They were also rated for the impact of Leptocybe invasa. Leptocybe invasa was capable of feeding and forming galls on 13 species from six sections within Eucalyptus and one species of Corymbia. The impact was greater in the nursery. Five of the Eucalyptus spp. which were susceptible in the nursery were not damaged in the field. The most susceptible hosts in Vietnam were E. camaldulenis, E. grandis, and E. tereticornis, both in the nursery and field trial. Variation in the susceptibility of provenances of E. camaldulensis, E. urophylla, and E. grandis were observed, which is promising for breeding for resistance and long-term control.