The galling insect Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae) is a major limiting factor in the cultivation of drought-tolerant eucalyptus. The insect L. invasa is a major pest of eucalyptus plantations, and Beauveria bassiana (Bals.) Vuill (Ascomycota: Hypocreales) is being investigated as a potential biocontrol agent against this pest. The fungus B. bassiana can produce metabolites that affect insect biology and survival. Here, we investigated the ability of the entomopathogenic B. bassiana to endophytically develop and induce resistance to L. invasa in a drought-tolerant eucalyptus hybrid. In a greenhouse under semi-controlled conditions, a group of seedlings were sprayed with a solution containing the fungal spores of B. bassiana. The uninoculated seedlings and seedlings inoculated were infested with L. invasa, and their morphometric responses, gas exchange, and chlorophyll indexes were assessed. The number of leaves and height of the inoculated plants was higher than those of the uninoculated plants. The mean CO2 assimilation rate (A) and transpiration rate (E) were higher for inoculated plants. The inoculated plants showed higher chl a and chl b contents. Compared to the uninoculated plants, the inoculated plants developed much fewer galls, while some showed only scar formations where L. invasa deposited its eggs. These results indicated that inoculating Eucalyptus with B. bassiana promoted resistance to L. invasa. To the best of our knowledge, this is the first study showing that an entomopathogenic fungus can develop endophytically to promote resistance against a galling insect pest.

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RESUMO:Com o presente trabalho, objetivou-se comparar a estimativa visual de altura e quatro instrumentos hipsométricos baseados no princípio geométrico com o hipsômetro Suunto, que é um hipsômetro baseado no princípio trigonométrico. Os dados foram coletados em uma área de cerrado localizada na região sul do estado de Tocantins e divididos em três classes de altura: 1 (h < 7 m); 2 (7 < h < 9 m); e 3 (h > 9 m). Para cada classe, foi medida a altura de dez árvores e a avaliação dos instrumentos se deu através da análise de variância em parcelas subdivididas, com posterior aplicação do teste para comparação de médias de Dunnett. Os resultados mostraram que o método de estimação visual de altura é eficiente quando comparado ao Suunto apenas para árvores com altura maiores a 7 m; o método do bastão não se mostrou eficiente em nenhuma das classes; o método do graveto se mostrou eficiente apenas para árvores menores ou iguais a 7 m; o hipsômetro Christen e a prancheta dendrométrica se mostraram eficientes em todas as classes de altura estudadas, entretanto, a última, obteve maior precisão. Portanto, de maneira alternativa ao Suunto, a prancheta dendrométrica foi o instrumento mais indicado em áreas de Cerrado tocantinense. Palavras-chave: hipsômetro Suunto, prancheta dendrométrica, altura das árvores.Hypsometers assessment based on the geometric principle in area of savanna ABSTRACT: This study aimed to compare four hypsometric instruments based on the geometric principle and visual estimation of height with Suunto hypsometer based on trigonometric principle. The data were divided into three classes in height, they were collected in a savannah area located in the southern region of Tocantins. For each class, the height was measured ten trees and evaluation of instruments was made through the analysis of variance in a split plot, with subsequent application of the test for medium Dunnett comparison. It was concluded that the visual estimation method is time efficient when compared to Suunto only trees with increased height of 7 m; Method bat not efficient in any of the classes; the method of stick proved efficient only for smaller trees or equal to 7 m; the Christen hypsometer and dendrometric clipboard were efficient in all studied height classes. Among these instruments, the Suunto alternatively, the dendrometric clipboard was the most appropriate instrument in Tocantins savanna areas.

BACKGROUND: Here, we investigated changes in primary metabolism and cell death around oviposition sites in two hybrid clones of Eucalyptus with different degrees of resistance to Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae), as well as tolerance to water deficiency. RESULTS: We showed that apices of the resistant clone with oviposition had a higher content of amino acids, organic acids and the compound putrescine compared with those of the susceptible clone with oviposition. By contrast, apices of the resistant clone with oviposition had lower sugar and pyruvate organic acid content than those of the susceptible clone with oviposition. Small areas of necrosis were induced around the oviposition sites in the stem apices of Eucalyptus 24 h after infestation. The resistant clone developed larger necrotic areas that showed progressive increases 24-72 h after infestation compared with the susceptible clone, in which cell death was significantly lower and no changes were observed in necrotic area over time. Thus, the programmed death of cells around the egg, modulated by several amino acids, is likely the first defence response of Eucalyptus against L. invasa.CONCLUSION: Our results serve as the basis for the early identification of key metabolites produced in plants in defence against galling insects.