Suitable areas for invasive insect pests in Brazil and the potential impacts for eucalyptus forestry.

BACKGROUND: Brazil is among the world's largest producers of eucalyptus and the damage caused by native and invasive insect pests is one of the main factors affecting eucalyptus yield. The recent history of biological invasions of eucalyptus pests in Brazil prompts demand for phytosanitary measures to prevent new invasions. This study used ecological niche models to estimate suitable areas for nine eucalyptus pests. This information was used to assess the potential ports of entry, generate invasion risk maps considering the likelihood of introducing invasive species, and estimate the eucalyptus producing municipalities and areas within the species' suitable range. RESULTS: A large distribution range was predicted for Eucalyptolyma maideni (Hempitera: Aphalaridae), Orgya postica (Lepidoptera: Erebidae), Sinoxylon anale (Coleoptera: Bostrichidae), and Trachymela sloanei (Coleoptera: Chrysomelidae) in Brazil, while a comparatively smaller distribution was predicted for Ophelimus maskelli (Hymenoptera: Eulophidae), Mnesampela privata (Lepidoptera: Geometridae), Paropsis atomaria (Coleoptera: Chrysomelidae), Paropsisterna beata, and P. cloelia (Coleoptera: Chrysomelidae). High-risk areas of invasion near airports and seaports were predicted mainly in southern, southeastern, and northeastern Brazil. A large proportion of the municipalities (24.4% to 93.7%) and areas with eucalyptus plantations (31.9% to 98.3%) are within the climatically suitable areas estimated for the pests, especially in southern and southeastern regions, which comprises 61.5% of the Brazilian eucalyptus production. CONCLUSION: The results indicate that eucalyptus forestry may be significantly impacted by biological invasion. The findings provided by our study can assist decision-makers in developing phytosanitary measures to prevent new invasions of forest pests in Brazil. © 2022 Society of Chemical Industry.

Cell death and changes in primary metabolism: the onset of defence in Eucalyptus in the war against Leptocybe invasa.

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. © 2022 Society of Chemical Industry.

How can global climate change influence the geographic distribution of the eucalyptus yellow beetle? Modeling and prediction for Brazil / Como mudanças climáticas globais podem influenciar na distribuição geográfica do besouro amarelo do eucalipto? Modelagem e predição para o Brasil

Popularly known as the yellow eucalyptus beetle, Costalimaita ferruginea (Fabricius, 1801) (Coleoptera: Chrysomelidae), in the adult phase it feeds on the leaves of the myrtaceae, leaving them laced, a fact that impairs the productivity of plantations. Therefore, this work aims to model the potential distribution of the beetle in climate change scenarios for Brazil. The biotic data were collected through a review of the literature and entomological collections, totaling 88 georeferenced points of occurrence of the insect in the country. The abiotic data (19 biovariables, precipitation and minimum, average and maximum temperature) in the Wordcllim database, represent the periods: current (1970-2000), middle (2041-2060), and final (2061-2080) of the century, with representation in two projections of climatic anomalies (RCP 4.5 and RCP 8.5). To determine the most important variables for the models, the Jackknife test was performed in the Maxent software, which resulted in five biovariables, namely: annual precipitation (35.2%), temperature seasonality (15.2%), annual temperature variation (13.7%), seasonality of precipitation (8.7%) and an average temperature of the coldest quarter (7.4%). Subsequently, the Openmodeller software was used and five algorithms were tested to determine which model represents the prediction of areas of suitability for the occurrence of the insect. The algorithm that best represented the appropriate areas was the Envelope Score (AUC = 0.808), corroborating the occurrence data collected. The prediction shows that the Pampa biome, in the RCP8.5 scenario for the period between 2061-2080, will become fully suitable for the occurrence of this defoliator beetle, unlike the Amazon, which presents retraction in areas suitable for the occurrence of the beetle for the same period. In this sense, commercial eucalyptus plantations implemented in climatologically suitable areas for the occurrence of this insect must be monitored periodically.

Conhecido popularmente como, o besouro-amarelo do eucalipto, Costalimaita ferrugínea (Fabricius, 1801) (Coleoptera: Chrysomelidae), na fase adulta alimenta-se das folhas da mirtácea deixando-as rendilhadas, fato este que prejudica a produtividade dos plantios. Sendo assim, este trabalho tem como objetivo modelar a distribuição potencial do besouro em cenários de mudanças climáticas para o Brasil. Os dados bióticos foram levantados através de revisão de literatura e de coleções entomológicas, totalizando 88 pontos georreferenciados de ocorrência do inseto no país. Os dados abióticos (19 biovariáveis, precipitação e temperatura mínima, média e máxima) no banco de dados Wordlclim, representando os períodos: atual (1970-2000), meio (2041-2060) e final (2061-2080) do século, com representação em duas projeções de anomalias climáticas (RCP 4.5 e RCP 8.5). De modo a determinar as variáveis mais importantes para os modelos, foi realizado o teste Jackknife no software Maxent, o qual resultou em cinco biovariáveis, sendo elas: precipitação anual (35.2%), sazonalidade da temperatura (15.2%), variação anual de temperatura (13.7%), sazonalidade de precipitação (8.7%) e temperatura média do trimestre mais frio (7.4%). Posteriormente, utilizou-se o software Openmodeller e testados cinco algoritmos, para determinar qual modelo representa a predição de áreas de adequabilidade para a ocorrência do inseto. O algoritmo que melhor representou as áreas adequadas foi o Envelope Score (AUC = 0.808), corroborando com os dados de ocorrência levantados. A predição mostra que o bioma Pampa, no cenário RCP8.5 para o período entre 2061-2080 se tornará totalmente adequado à ocorrência desse besouro desfolhador, ao contrário da Amazônia, que apresenta retração nas áreas adequadas à ocorrência do besouro para o mesmo período. Nesse sentido, plantios comerciais de eucalipto implementados em áreas climatologicamente adequadas à ocorrência desse inseto devem ser monitoradas periodicamente.

Differential development times of galls induced by Leptocybe invasa (Hymenoptera: Eulophidae) reveal differences in susceptibility between two Eucalyptus clones.

BACKGROUND: The significance of morphological responses of hosts on susceptibility against gall-inducing insects is relatively unknown, especially in planted forests. Here, we investigate the temporal morphological responses (gall development) induced by the invasive gall wasp Leptocybe invasa and the subsequent insect development in two Eucalyptus clones. RESULTS: Our results identified a novel stage of gall development, not previously reported, termed here 'brownish ring'. In both hosts similar gall development stages were observed. Although L. invasa oviposited in both clones, comparison of external morphological traits of galls over time revealed a differential response in the number of galls between clones. Comparison of the developmental time of each gall and insect stage between clones suggests that plant defense mechanisms against L. invasa are activated shortly after oviposition by the wasp, yet before gall formation. CONCLUSION: Gall number is an important parameter that should be used to measure host susceptibility among Eucalyptus clones. To the best of our knowledge, this is the first study showing differential morphological responses induced by a galling insect, even before gall formation, revealing differences in susceptibility between different plant hosts. These findings provide insight into the use of early stages of gall formation by L. invasa to prevent invasion and establishment of this pest.

Influence of Temperature and Precipitation Anomaly on the Seasonal Emergence of Invasive Bark Beetles in Subtropical South America.

Several invasive bark beetle species have caused major economic and ecological losses in South America. Accurate predictions of beetle emergence times will make control efforts more efficient and effective. To determine whether bark beetle emergence can be predicted by season, temperature, or precipitation, we analyzed trapping records for three introduced pest species of bark beetles in Uruguay. We used trigonometric functions as seasonal predictors in generalized linear models to account for purely seasonal effects, while testing for effects of temperature and precipitation. Results show that all three beetle species had strong but unique seasonal emergence patterns and responded differently to temperature and precipitation. Cyrtogenius luteus (Blandford) emerged in summer and increased with precipitation but was not affected by temperature. Hylurgus ligniperda (Fabricius) emerged in winter and increased with temperature but was not affected by precipitation. Orthotomicus erosus (Wollaston) had a primary emergence in spring, and a smaller emergence in early summer, but showed no significant relationship with temperature or precipitation. This study shows that the emergence of these bark beetle species in Uruguay is influenced by seasonality more than by temperature and precipitation fluctuations. It also shows how seasonality can be easily incorporated into models to make more accurate predictions about pest population dynamics.

Forrageamento e sobrevivência de colônias do cupim Nasutitermes sp em laboratório / Foraging and maintenance of Nasutitermes sp colonies (Isoptera: Termitidae) in laboratory

Os cupins são insetos sociais da ordem Isoptera, com cerca de 2.900 espécies catalogadas no mundo. No Brasil, são várias as espécies de importância agrícola e florestal. Caracterizam-se por colônias complexas do ponto de vista social e estrutural, muitas vezes subterrâneas, o que dificulta o seu completo conhecimento. Diante deste fato, este trabalho teve como objetivo a criação de colônias de cupins com importância agrícola em laboratório, para determinar as condições necessárias ao seu desenvolvimento, incluindo preferências de forrageamento. Colônias jovens foram coletadas em campo e mantidas em laboratório, num sistema artificial com condições estruturais (abrigo) e ambientais (luz, temperatura, umidade relativa do ar) que buscaram ser as mais similares possíveis àquelas naturais. Diferentes substratos foram oferecidos como opção alimentar. Após estabelecimento da criação laboratorial e observação do forrageamento de colônias do cupim Nasutitermes sp, verificou-se a preferência de forrageamento por raiz, seguida de matéria orgânica, folhas secas e frescas, equivalentemente. Verificou-se também sua adaptação à um sistema estrutural artificial composto por caixa central e caixa de alimentação, permitindo a manutenção das colônias por tempo indeterminado.

Termites are social insects of Isoptera order, with about 2,900 species cataloged in the world. In Brazil, there are several species of agricultural and forestry importance. They are characterized by complex colonies from the social and structural point of view, often subterranean, which hinders their complete knowledge. In view of this fact, this work had as objective the breeding of termite colonies with agricultural importance in the laboratory, of the genus Nasutitermes, to determine the necessary conditions for its development, including foraging preferencesfor different parts of Paspalum notatum. Young colonies were collected in field and kept in laboratory, in an artificial system with structural conditions (shelter) and environmental conditions (light, temperature, relative humidity) that sought to be the most similar to those natural ones. Different parts of P. notatum were offered as food option, in a test with a chance of choice. After establishing of laboratory rearingand observing the foraging of Nasutitermesspp. colonies, it was verified the preference of foraging by root, followed by decaying fragments, dry and fresh leaves, equivalently. It was also verified its adaptation to an artificial structural system composed of central box and feeding box, allowing the maintenance of the colonies for a minimum period of 5 months.

Forrageamento e sobrevivência de colônias do cupim Nasutitermes sp em laboratório / Foraging and maintenance of Nasutitermes sp colonies (Isoptera: Termitidae) in laboratory

Os cupins são insetos sociais da ordem Isoptera, com cerca de 2.900 espécies catalogadas no mundo. No Brasil, são várias as espécies de importância agrícola e florestal. Caracterizam-se por colônias complexas do ponto de vista social e estrutural, muitas vezes subterrâneas, o que dificulta o seu completo conhecimento. Diante deste fato, este trabalho teve como objetivo a criação de colônias de cupins com importância agrícola em laboratório, para determinar as condições necessárias ao seu desenvolvimento, incluindo preferências de forrageamento. Colônias jovens foram coletadas em campo e mantidas em laboratório, num sistema artificial com condições estruturais (abrigo) e ambientais (luz, temperatura, umidade relativa do ar) que buscaram ser as mais similares possíveis àquelas naturais. Diferentes substratos foram oferecidos como opção alimentar. Após estabelecimento da criação laboratorial e observação do forrageamento de colônias do cupim Nasutitermes sp, verificou-se a preferência de forrageamento por raiz, seguida de matéria orgânica, folhas secas e frescas, equivalentemente. Verificou-se também sua adaptação à um sistema estrutural artificial composto por caixa central e caixa de alimentação, permitindo a manutenção das colônias por tempo indeterminado.(AU)

Termites are social insects of Isoptera order, with about 2,900 species cataloged in the world. In Brazil, there are several species of agricultural and forestry importance. They are characterized by complex colonies from the social and structural point of view, often subterranean, which hinders their complete knowledge. In view of this fact, this work had as objective the breeding of termite colonies with agricultural importance in the laboratory, of the genus Nasutitermes, to determine the necessary conditions for its development, including foraging preferencesfor different parts of Paspalum notatum. Young colonies were collected in field and kept in laboratory, in an artificial system with structural conditions (shelter) and environmental conditions (light, temperature, relative humidity) that sought to be the most similar to those natural ones. Different parts of P. notatum were offered as food option, in a test with a chance of choice. After establishing of laboratory rearingand observing the foraging of Nasutitermesspp. colonies, it was verified the preference of foraging by root, followed by decaying fragments, dry and fresh leaves, equivalently. It was also verified its adaptation to an artificial structural system composed of central box and feeding box, allowing the maintenance of the colonies for a minimum period of 5 months.(AU)

Predicting North American Scolytinae invasions in the Southern Hemisphere.

Scolytinae species are recognized as one of the most important tree mortality agents in coniferous forests worldwide, and many are known invaders because they are easily transported in wood products. Nonnative trees planted in novel habitats often exhibit exceptional growth, in part because they escape herbivore (such as Scolytinae) pressure from their native range. Increasing accidental introductions of forest pest species as a consequence of international trade, however, is expected to diminish enemy release of nonnative forest trees. In this context, there is need to characterize patterns of forest herbivore species invasion risks at global scales. In this study, we analyze the establishment potential of 64 North American Scolytinae species in the Southern Hemisphere. We use climate-based ecological niche models (MaxEnt) to spatially define the potential distribution of these Scolytinae species in regions of the Southern Hemisphere were pines are planted. Our model predicts that all of the pine-growing regions of the Southern Hemisphere are capable of supporting some species of North American Scolytinae, but there are certain "hotspot" regions, southeastern Argentina, Bolivia, Chile, Peru and southwestern Australia, that appear to be suitable for a particularly large number of species. The species with the highest predicted risk of establishment were Dendroctonus valens, Xyleborus intrusus, Hylastes tenuis, Ips grandicollis, Gnathotrichus sulcatus, and Ips calligraphus. Given that global commerce is anticipated to continue to increase, we can expect that more Scolytinae species will continue to establish outside their range. Our results provide information useful for identifying a global list of potential invasive species in pine plantations, and may assist in the design of comprehensive strategies aimed at reducing pest establishment in Southern Hemisphere forest plantations.

Persistence of fipronil residues in Eucalyptus seedlings and its concentration in the insecticide solution after treatment in the nursery.

Eucalyptus seedlings are normally protected from underground termites (Isoptera: Termitidae) by immersing them in insecticide solutions. Fipronil (phenylpyrazole) is the most frequently used product to protect seedlings in the field for up to 6 months after application. This is performed just prior to planting. However, the persistence of this product in seedlings that are treated and subjected to irrigation several days prior to planting has not yet been evaluated. This study aims to quantify the fipronil concentration in the substratum and roots of the seedlings treated and subjected to irrigation for up to 56 days prior to planting and to quantify this insecticide concentration in the solutions, without continuous stirring, for 120 min. The quantitative determination of fipronil in the seedlings and in the insecticide solution was done by high-performance liquid chromatography (HPLC) with an ultraviolet (UV) detector. It was found that irrigation up to 56 days, performed in the nurseries, did not decrease the fipronil concentration in the seedlings. The absence of stirring reduced the fipronil concentration in the insecticide solution, necessitating a homogenization system to maintain the recommended concentration of this product, to effectively treat the eucalyptus seedlings. The seedling treatment with fipronil can be conducted strictly in the nursery, reducing cost and environmental risks.