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Abstract

ABSTRACT: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.

Current Infestation Status and Damage Severity of Eucalyptus Gall Wasps, Leptocybe invasa (Fisher & La Salle), and Ophelimus maskelli Ashmead (Hymenoptera: Eulophidae), Infesting Eucalyptus Germplasms in Tanzania

“…The intensity of the damage was determined using subjective visual criteria and a formula developed by several authors. [26,27]; 60 trees were specifically selected. The severity score based on the percentage of leaves affected ranges 0 -4, and presented as follows: 1) score 0, for healthy tree, no damage; 2) score 1, when ˂25% leaves and twigs of crown infested; 3) score 2, when 25 -50% leaves and twigs of crown infested; 4) score 3, when >50 -75% leaves and twigs of crown infested; and 5) score 4, when >75% leaves and twigs of crown infested.…”

The value of sentinel plants for risk assessment and surveillance to support biosecurity

“…Sentinel plants for risk assessment and surveillance can be used not only for the primary purpose of identifying and detecting new potential invaders (e.g. Stevens 2008;Tomoshevich et al 2013;Vettraino et al 2017;, but also to test either general ecological theories about biological invasions (Kirichenko et al 2013;Kirichenko and Kenis 2016;Burgess and Wingfield 2017) or specific hypotheses about particular invasive species (Thu et al 2009;Rathe et al 2014;Kurose et al 2015). Some sentinel plant programs address both purposes (Roques et al 2015;Vettraino et al 2015;Eschen et al 2018).…”

A review of the introduced forest pests in Brazil

“…It was first observed in Israel in 2000 and has since spread rapidly (Thu et al, 2009). This wasp is a devastating pest of eucalyptus plantations, woodlots, and urban trees (Thu et al, 2009).…”

“…It was first observed in Israel in 2000 and has since spread rapidly (Thu et al, 2009). This wasp is a devastating pest of eucalyptus plantations, woodlots, and urban trees (Thu et al, 2009). Leptocybe invasa displays thelytokous reproduction, forming typical bump-shaped galls on the leaf midribs, petioles, and stems of new growth of several Eucalyptus species (Garlet et al, 2013).…”

“…In Brazil, the wasp is already established in several states, such as Bahia, São Paulo, Minas Gerais, Mato Grosso do Sul, Tocantins, Maranhão, Pernambuco, Paraná, Santa Catarina, and Rio Grande do Sul (Costa et al, 2008;Wilcken et al, 2010bWilcken et al, , 2012Garlet et al, 2013;Rinaldi et al, 2013 (Thu et al, 2009). The most threatened species is E. camaldulensis (Garlet et al, 2013), followed by E. grandis, E. tereticornis (all three susceptible to severe damage), and E. saligna (susceptible to medium damage) (Thu et al, 2009). The last three species are largely cultivated in Brazil, and the mentioned study made it possible to rank the vulnerability of the Brazilian commercial species of eucalyptus to the insect.…”