Comportamiento de Eucalyptus grandis frente al ataque de Leptocybe invasa en un ensayo clonal en el departamento de Tacuarembó

The Uruguayan forestry sector has been characterized by the implementation of large areas with a low genetic diversity, a few numbers of species and from clonal origin. Eucalyptus grandis is currently the most planted species, with more than 250,000 ha of forest plantations older than 3 years. The entry of new pests into the country supposes an eventual health risk that compromises the stability of these monocultures, such as the galling wasp of the eucalyptus Leptocybe invasa (Hymenoptera: Eulophidae). In Uruguay, the presence of this pest insect species was noted for the first time in 2011, becoming a problem for plantations since it was detected. The main damages are associated with the formation of galls on the main veins, leaves petioles, branches and even trunks of young plants, which causes symptoms such as leaves deformation resulting in a reduction of the photosynthetic area and a loss of growth. This generates a state of stress in the plant which predisposes it to the attack of secondary pests or even in severe attacks can cause their death. The objective of this work was to evaluate the susceptibly of different clones of E. grandis to the attack by the galling wasp of the eucalyptus L. invasa, in a clonal trial located in the department of Tacuarembó. A total of 164 clones and 11 commercial controls were evaluated by means of a DBCA consisting of 370 plots distributed in four blocks (stands). The level of damage was measured at the age of 6 months using a visual scale and the model describing its behavior is a Mixed Generalized Linear Model (GLMM), with the Clone variable as a fixed effect and the variables Plot and Block as random effects. No plots were observed without damage, that means, all the clones evaluated showed attack symptoms to a greater or lesser extent. The Deviancy analysis indicates that the Clone variable was significant in the model with a p-value of 7.288e-16, indicating that there is an effect of the genotype on the response to the damage level. However, the post-hoc Tukey Test did not show major differences between the clones evaluated.