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

Abstract

Abstract Eucalypts spp., are the most popular hardwood timber species in the world, indigenous to Australia, Indonesia, the Philippines, Timor, and New Guinea. Distribution is attributable to their exceptionally high ability to adapt to diverse ecological conditions and the substantially varying products and services they offer. Leptocybe invasa and Ophelimus maskelli are serious pests causing damage to eucalypt plantations in Tanzania. Due to limited knowledge and literature, a study assessed the infestation status and damages of two gall inducers on three government plantations, namely Korogwe, North Ruvu, and Morogoro forests planted with several Eucalypt species, including E. tereticornis and hybrids of E. grandis x E. camadulensis, from October 2021 to April 2022, through assessments of percentage of infested leaves in three crown parts, the association between stand elevations and the infestation magnitude and damage index. Microsoft Excel and Minitab 19 statistical software were used to analyze the data. Results showed positive correlations between wasp infestations and stand altitude among eucalypt germplasms. Clonal hybrids were more infested. The middle crown part was highly infested, followed by the lower crown part at p= 0.880 and p= 0.641 respectively. L.invasa had a higher invasive capacity than O. maskelli. Control efforts should focus on biological control and greenhouse-gall screening to get resistant genotypes. Nevertheless, mass trapping using a yellow sticky trap and a cattle stable can be used for monitoring the pest population immediately.