ABSTRACT Wasps that belong to the genus Ophelimus develop galls on Eucalyptus spp., and E. globulus is considered among the most susceptible species. In 2003, a new species of Ophelimus was detected in Chile. This species forms galls on E. globulus and E. camaldulensis, and it was recently considered as Ophelimus migdanorum nov sp. The present study was carried out 16 yr after its detection and it was aimed to determine the presence of Ophelimus in plantations of E. globulus located in Maule, Biobío and La Araucanía Regions, which represent 76% of the area covered with this species in the country. Between August and September 2017, a total of 165 sampling forest farms were established in stands of E. globulus, located in these regions of the country. In each farm, twigs were collected that represented formation of galls and maintained in laboratory conditions until the emergence of adults. These were identified according to their external morphological characteristics. The presence of O. migdanorum and Closterocerus chamaeleon was determined. Both species emerged together in all the regions considered in the study, 92.1% and 46.7% of the evaluated forest farms, respectively. Then Ophelimus migdanorum is widely distributed in Maule, Biobío and La Araucanía Regions, in Chile

RESUMO Quatro sistemas de colheita de madeira foram avaliados nas atividades de desbaste de povoamentos de Pinus radiata (harvester-forwarder, motosserra-skidder, motosserra-carregadora de três rodas e motosserra-yarder), considerando seu impacto no percentual de árvores e superfície afetada. Adicionalmente, foi analisado o efeito combinado do sistema colheita e estação do ano (verão e inverno), na incidência e área de injúria, e sua relação com o diâmetro das árvores. Entre os sistemas de colheita estudados, aqueles que utilizaram motosserra-yarder e harvester-forwarder tiveram maior incidência de injúria mecânica nas árvores, atingindo 34,5% e 32,2%, respectivamente; como também em uma maior área injuriada por árvore com 349.7 e 427.2 cm2, respectivamente. A estação do ano para as operações de colheita foi um fator que aumentou significativamente o número de árvores com algum nível de injúria, variando entre 27,1% no inverno e 10,1% no verão. Entretanto, o estudo mostrou também que a extração da árvore com o forwarder e yarder tem um alto potencial de dano residual no povoamento, sendo que sua estrutura não foi afetada pelo desbaste mecanizado, porque foram danificadas árvores em todas as classes de tamanho.

ABSTRACT The effect of four harvesting systems for thinning tasks (harvester-forwarder, chainsaw-skidder, chainsaw-three-wheeled loader and chainsaw-yarder) was evaluated on percentage of damaged trees and damage surface. Additionally, the effect of the logging system and the season of the operation (winter and summer) on the incidence of damage and surface of the injuries, and their relationship with tree diameter, was also analyzed. Of the four logging systems studied, those carried out with chainsaw-yarder and harvester-forwarder originated the greater incidence of damage with 34.5% and 32.2%, respectively, also producing the greatest injuries with 349.7 and 427.2 cm2, respectively, by individual tree. The season in which the operations were conducted is a factor that significantly affected on the increase of the number of trees with some sort of damage, with an average incidence of 27.1% in winter and 10.1% in summer. In addition, tree extraction with forwarder and yarder has a high potential for residual stand damage, and the stand structure was not affected by mechanized thinning, because there were damages in all sizes of remaining trees.

ABSTRACT In Chile, the Eucalyptus nitens (H. Deane & Maiden) Maiden × E. globulus Labill. hybrid presents the highest production potential due to its desirable characteristics for the production of cellulose. Nevertheless, its low ability to rooting complicates the clonal propagation in nurseries, with the need for new alternatives to increase rooting. The objective of this research was to evaluate the effect of rhizobacteria in the adventitious rooting of mini-cuttings of two hybrid E. nitens × E. globulus clones, wherein 106 rhizospheric bacterial isolates from five species and hybrids of Eucalyptus spp. were used. The mini-cuttings were treated at the base with a 20 mL liquid suspension of rhizobacterial strains. In addition, cultured bacteria were applied by manual sprinklers in the rooting substrate. In the first trial, 38% of rhizobacteria increased significantly rooting of X-64 clone mini-cuttings. Of these, in a second trial, 50% of rhizobacteria maintained their effect in promoting the rooting in two clones, and in the third trial among the 20 strains evaluated, 10 strains increased rooting in both clones. The rhizobacteria that had the most consistent effect in the rooting increase of the mini-cuttings were species of Bacillus and Pseudomonas sp., as well as the genera Chryseobacterium, Mucilaginibacter and Rhodococcus sp., with these results, it is concluded that 10 rhizobacterial isolates have increased the adventitious rooting of minicuttings of two hybrid clones of E. nitens × E. globulus, and these inoculants could be used in periods of underperformance of minicuttings, in order to optimize their performance.

ABSTRACT Twenty-one Clonostachys rosea strains, previously selected by its biocontrol activity higher than 80% against Fusarium circinatum, were evaluated for its ability to promote growth of Pinus radiata seedlings on natural substrate. Stem height, root length, dry weight of stem and roots, and ectomycorrhization were measured at 102 days after seeding. The results showed significant differences between some of the tested C. rosea strains when compared to the controls, showing increases for plant height of 25%, dry stem mass of 37%, root length of 13.5%, dry root mass of 20.5% and ectomycorrhization of 55% when compared to their respective controls, demonstrating a possible dual use of these strains for both plant protection and increased biomass of P. radiata.

RESUMEN Veintiún aislamientos de C. rosea, previamente seleccionadas por su actividad de biocontrol superior al 80% contra Fusarium circinatum, fueron evaluadas en su habilidad para promover el crecimiento de plántulas de Pinus radiata sobre substrato natural. Las variables altura de tallo, longitud de raíz, masa seca de tallo y raíz, y ectomicorrización fueron medidas a los 102 días posterior a la siembra. Los resultados muestran el aumento significativo de las variables evaluadas con la aplicación de algunos de los aislamientos de C. rosea, alcanzando incrementos del 25% en altura, 37% en peso seco del tallo, 13,5% en la longitud de la raíz, 20,5% en peso seco de la raíz, y 55% de ectomicorrización, demostrando un posible uso dual de estas cepas tanto para protección fitosanitaria como para incremento en la biomasa de P. radiata.

ABSTRACT Fusarium circinatum is the fungus that causes the disease "canker" (pitch canker), which affects many species of conifers. This review describes the state of the art of F. circinatum worldwide and the current situation in Chile, covering the history of the pathogen and the disease. In Chile, the pathogen was detected in Pinus radiata hedges in late 2001, being present today in 39 of 196 nurseries, located between the regions of O'Higgins and Los Ríos. After 14 years of the detection of F. circinatum, the pathogen has not attacked commercial plantations of P. radiata. Measures for integrated disease management, where genetic resistance constitutes the main strategy in a scenario in which pitch canker could appear in commercial plantations of P. radiata in Chile.

RESUMEN Fusarium circinatum es el hongo causante de la enfermedad "cancro resinoso" (pitch canker), que afecta numerosas especies de coníferas. En esta revisión se describe el estado del arte de F. circinatum a nivel mundial y su situación actual en Chile, abarcando antecedentes del patógeno y de la enfermedad. En Chile, el patógeno fue detectado en setos de Pinus radiata a fines de 2001, encontrándose hoy presente en 39 viveros de un total de 196, ubicados entre las regiones de O'Higgins y de Los Ríos. Después de 14 años de la detección de F. circinatum en Chile, el patógeno no ha presentado diseminación en las plantaciones comerciales de P. radiata. Se destacan las medidas para el manejo integrado de la enfermedad, donde la resistencia genética sería la principal estrategia ante un escenario en que el cancro resinoso se presente en las plantaciones comerciales de P. radiata en Chile.

Rhizospheric and endophytic bacteria were isolated from the rizosphere and root tissue of Eucalyptus nitens. The objective of this work was to evaluate their capacity to promote growth in seedlings of the same species under greenhouse conditions. The isolates that improved seedling growth were identified and characterized by their capacity to produce indoleacetic acid (IAA), solubilize phosphates and increase 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. One hundred and five morphologically different strains were isolated, 15 of which promoted E. nitens seedling growth, significantly increasing the height (50%), root length (45%) as well as the aerial and root dry weight (142% and 135% respectively) of the plants. Bacteria belonged to the genus Arthrobacter, Lysinibacillus, Rahnella and Bacillus. Isolates A. phenanthrenivorans 21 and B. cereus 113 improved 3.15 times the emergence of E. nitens after 12 days, compared to control samples. Among isolated R. aquatilis, 78 showed the highest production of IAA (97.5±2.87 μg/ml) in the presence of tryptophan and the highest solubilizer index (2.4) for phosphorus, while B. amyloliquefaciens 60 isolate was positive for ACC deaminase activity. Our results reveal the potential of the studied rhizobacteria as promoters of emergence and seedling growth of E. nitens, and their possible use as PGPR inoculants, since they have more than one mechanism associated with plant growth promotion.

Se aislaron bacterias rizosféricas y endófitas a partir de rizósfera y tejidos de raíz de árboles de Eucalyptus nitens con el objetivo de evaluar su capacidad de promover el crecimiento en plántulas de la misma especie en condiciones de invernadero. Los aislamientos que incrementaron el crecimiento de las plántulas fueron identificados y caracterizados por su capacidad de producir ácido indolacético (AIA), solubilizar fosfato y expresar la 1-aminociclopropano-1-carboxilato (ACC) desaminasa. Los 105 aislamientos obtenidos fueron morfológicamente diferentes y solo 15 promovieron significativamente el crecimiento de plántulas de E. nitens. Los máximos incrementos observados fueron en el peso seco aéreo (142 %) y de la raíz (135 %); también aumentaron la altura de las plantas (50 %) y el largo de raíces (45 %) de las mismas. Las rizobacterias pertenecieron a los géneros Arthrobacter, Lysinibacillus, Rahnella y Bacillus. Los aislados identificados como A. phenanthrenivorans 21 y B. cereus 113 incrementaron la emergencia de E. nitens a los 12 días en un valor promedio de 3,15 veces con relación al control. R. aquatilis aislado 78 presentó la mayor producción de AIA (97,5 ± 2,87 μg/ml) en presencia de triptófano y el mayor índice de solubilización de fósforo (2,4). B. amyloliquefaciens aislado 60 fue positivo para la actividad ACC desaminasa. Los resultados obtenidos indican el potencial de las rizobacterias estudiadas como promotoras de emergencia y crecimiento de plántulas de E. nitens y su posible uso como inoculantes, ya que presentan más de un mecanismo de acción asociado a la promoción del crecimiento.

Swiss needle cast is a disease caused by Phaeocryptopus gaeumannii, a fungal pathogen causing severe defoliation in Pseudotsuga menziesii (Douglas fir) in some countries of the world, leading to losses in the volume of timber harvesting. This pathogen is distributed in the native range of P. menziesii in North America (U.S., Canada and Mexico) and has been introduced in Europe, New Zealand, Turkey and, recently, in Chile. Currently the country has an area larger than 16,000 ha of plantations of P. menziesii, which are increasing because it is a potentially productive species considered in species diversification programs. In Chile P. gaeumannii is distributed from the region of La Araucanía to Los Lagos, focusing on these areas the largest area of Douglas fir in the country (70 % approximately). The aim of this review was to examine studies related to biology and life cycle of the pathogen, epidemiology and infection processes, impact on plantations and control measures implemented in the different countries affected by this pathogen, in order to have a background take on the first studies to Chile, a referent to basic and applied research for the country.

El swiss needle cast o pérdida suiza de las acículas, es una enfermedad de carácter fungoso provocada por el patógeno Phaeocryptopus gaeumannii, organismo que causa severas defoliaciones en Pseudotsuga menziesii (pino oregón) en el mundo, originando pérdidas en el volumen de madera para cosechar. Este patógeno se distribuye en el rango nativo de P. menziesii en América del Norte (EE.UU., Canadá y México) y se ha introducido en Europa, Nueva Zelanda, Turquía y, recientemente en Chile. Actualmente, el país cuenta con una superficie superior a las 16.000 hectáreas de plantaciones de P. menziesii, las cuales van en aumento por tratarse de una especie con potencial productivo considerada en programas de diversificación de especies. En Chile P. gaeumannii se encuentra distribuido desde las regiones de La Araucanía a Los Lagos, concentrándose en estas zonas la mayor superficie de P. menziesii del país (70 % aproximadamente). El objetivo de esta revisión fue analizar estudios relacionados a la biología y ciclo de vida del patógeno, la epidemiología y procesos de infección, impacto en las plantaciones y medidas de control implementadas en los diferentes países afectados por este patógeno, de manera de contar con antecedentes científicos para realizar los primeros estudios en Chile, referentes a investigación básica y aplicada para el país.

The fungus Fusarium circinatum Nirenberg & O’Donnell causes pine pitch canker, an important disease for conifers worldwide. F. circinatum was first detected in Chile in 2001 and to date is present in nurseries and clonal hedges from Libertador General Bernardo O’Higgins Region to Los Rios Region. The purpose of this study was to evaluate the potential of Trichoderma spp. and Clonostachys spp. strains to control F. circinatum in Pinus radiata D. Don seedlings in the absence of other effective control methods. Eighty-one Trichoderma spp. and Clonostachys spp. strains were evaluated through in vitro assays to determine their ability to act as antagonists of F. circinatum and 21 strains were tested for their ability to reduce post-emergence mortality and increase P. radiata survival under greenhouse conditions. During in vitro experiments, 15 strains of Trichoderma inhibited mycelial growth of the pathogen by more than 60% and one strain of Clonostachys showed parasitism of F. circinatum hyphae. Greenhouse experiments showed no control of the disease when the antagonists were added to substrate after the pathogen. However, when the antagonists were added before the pathogen, four strains (Clonostachys UDC-32 and UDC-222 and Trichoderma UDC-23 and UDC-408) reduced post-emergence mortality between 80 and 100%. Among these strains, only Clonostachys UDC-222 significantly increased the survival of P. radiata seedlings. These results showed that Clonostachys UDC-222 has the potential to be used as a biocontrol agent against F. circinatum in the production of P. radiata plants.

Fusarium circinatum Nirenberg & O’Donnell es el hongo que causa el cancro resinoso del pino, una enfermedad de importancia mundial en coníferas. En Chile, F. cicirnatum fue detectado por primera vez el año 2001 y a la fecha se encuentra presente en algunos viveros y huertos clonales desde la Región del Libertador General Bernardo O’Higgins hasta la Región de Los Ríos. Debido a la ausencia de métodos eficientes para controlar este patógeno, el propósito de este estudio fue evaluar el potencial uso de cepas de Trichoderma y Clonostachys como control de F. circinatum en plántulas de Pinus radiata D. Don. Ochenta y un cepas de Trichoderma spp. y Clonostachys spp. fueron evaluadas a través de ensayos in vitro para determinar su habilidad para actuar como antagonistas de F. circinatum y 21 cepas fueron probadas por su habilidad para reducir la mortalidad post-emergencia e incrementar la supervivencia de P. radiata bajo condiciones de invernadero. Durante los experimentos in vitro, 15 cepas de Trichoderma inhibieron el crecimiento del patógeno más de un 60% y una cepa de Clonostachys mostró parasitismo de hifas de F. circinatum. En experimentos en invernadero, los antagonistas no controlaron la enfermedad cuando fueron agregados después de la inoculación del patógeno. Sin embargo, cuando los antagonistas fueron sembrados antes del patógeno, cuatro cepas (Clonostachys UDC-32 y UDC-222, Trichoderma UDC-23 y UDC-408) redujeron la mortalidad post-emergencia entre 80 y 100%. Entre estas cepas, sólo Clonostachys UDC-222 incrementó significativamente la supervivencia de plántulas de P. radiata. Estos resultados demuestran que Clonostachys UDC-222 posee gran potencial para ser empleado como agente de biocontrol contra F. circinatum en la producción de plantas de P. radiata.

Botrytis cinerea Pers. ex Fr. causes the disease known as gray mold in more than 200 hosts. It is one of the most important pathogens in Chilean forest nurseries and Eucalyptus globulus Labill. is one of the most susceptible species, especially in vegetative reproduction systems. Clonostachys and Trichoderma strains were selected as potential biocontrol agents of gray mold in previous research by the authors. The objective of this study was to evaluate the effectiveness of antagonistic fungi to control B. cinerea in E. globulus mini-cuttings. Five fungi strains were tested and applied weekly, two Clonostachys and three Trichoderma (5 x 10(6) conidia mL-1). In addition, comparison treatments were also used: absolute control (water) and fungicide application. The experiment was carried out under operational conditions to produce E. globulus mini-cuttings. The Clonostachys UDC-A10 and UDC-A11 strains reduce mini-cutting mortality caused by B. cinerea in 54 and 71%, respectively, and with effects similar to those achieved by fungicides. Clonostachys UDC-A11 reduces the disease progression rate with the same statistical results as fungicides. A negative effect of applying fungicides on rooting of the surviving mini-cuttings was also confirmed. These results demonstrate the effectiveness of Clonostachys as a control agent against gray mold disease in E. globulus mini-cuttings.

Botrytis cinerea Pers. ex Fr. ocasiona la enfermedad conocida como moho gris en más de 200 hospederos. En Chile es uno de los patógenos más importantes en viveros forestales, siendo Eucalyptus globulus Labill. una de las especies más susceptibles, especialmente en los sistemas de reproducción vegetativa. En investigaciones previas, realizadas por los autores, se seleccionaron cepas de Clonostachys y Trichoderma como potenciales agentes de biocontrol del moho gris. El objetivo fue evaluar la eficacia de hongos antagonistas en el control de B. cinerea en mini-estacas de E. globulus. Se probaron cinco cepas de hongos, dos de Clonostachys y tres de Trichoderma (5 x 10(6) conidias mL-1) aplicados semanalmente. Además, se utilizaron tratamientos para realizar comparaciones: control absoluto (agua) y aplicación de fungicidas. El ensayo se realizó bajo condiciones operacionales de producción de mini-estacas de E. globulus. Las cepas de Clonostachys UDC-A10 y UDC-A11 redujeron la mortalidad de las mini-estacas ocasionada por B. cinerea en 54% y 71%, respectivamente, con efectos similares a los logrados por los fungicidas. Clonostachys UDC-A11 redujo la tasa de incremento de la enfermedad con resultados estadísticamente similares a los obtenidos con fungicidas. Además, con la aplicación de fungicidas se constató un efecto negativo en el enraizamiento de las mini-estacas sobrevivientes. Estos resultados demuestran la eficacia de Clonostachys como agente de control contra la enfermedad del moho gris en mini-estacas de E. globulus.

Espécies de Rhizoctonia causam queima foliar em brotações de jardim clonal e podridão de estacas durante o enraizamento, que podem limitar a clonagem do eucalipto, por estaquia. Diante da importância do patógeno para a cultura e da falta de estudos sobre a diversidade de isolados, esse trabalho objetivou caracterizar isolados e relatar novos grupos de anastomose de Rhizoctonia spp. em jardim clonal de eucalipto. Os isolados obtidos nas diferentes fases de propagação por estaquia foram caracterizados quanto ao número de núcleos nas células vegetativas, agrupados segundo as características morfológicas das colônias e identificados quanto aos grupos de anastomose, incluindo auxotrofia por tiamina. Avaliou-se, também, a virulência ao eucalipto e o efeito da temperatura no crescimento micelial dos isolados. Não se detectou correlação entre os agrupamentos morfológicos e reações de anastomose. Constatou-se, também, que a população de Rhizoctonia spp., nos solos de jardins clonais, é constituída por ampla gama de isolados, predominantemente binucleados, com diferentes graus de virulência a eucalipto. Os isolados binucleados e os multinucleados, tiveram a mesma tendência de crescimento em relação à temperatura, com ótimo para a taxa de crescimento entre 25-30 ºC. Observou-se, pela primeira vez, isolados de R. solani AG2-2 IIIB e os binucleados de Rhizoctonia spp., AG-P e AG-O, como agentes etiológicos da podridão de estacas em casa de vegetação, e os isolados binucleados AG-A e AG-L em solo de jardim clonal de eucalipto.

Rhizoctonia spp. cause shoot and leaf blight of eucalyptus in clonal hedges as well as cuttings. Despite the importance of Rhizoctonia spp. to eucalyptus, little is known about their diversity. Thus, we characterized isolates and report new anastomosis groups in a eucalyptus clonal hedge. Isolates obtained at different stages of cutting propagation were characterized according to the number of nuclei in vegetative cells, grouped by morphological characteristics of the colony, anastomosis group, and thiamine auxotrophism. The isolates were also evaluated for virulence on eucalyptus and effect of temperature on their mycelial growth. No correlation between morphological grouping and anastomosis reaction was detected. A wide range of isolates, predominantly binucleate, forms the population of Rhizoctonia spp. present in the soil of clonal hedges, which differed in virulence to eucalyptus. Binucleate and multinucleate isolates had similar growth features at different temperatures, with an optimum growth rate between 25-30 ºC. Isolates of R. solani AG2-2 IIIB and binucleate isolates of Rhizoctonia spp., AG-P and AG-O, as agents of cutting rot, and binucleate isolates AG-A and AG-L in the soil of eucalyptus clonal hedge are reported for the first time.

A queima de folhas em brotações em jardim clonal e a mela de estacas na fase de enraizamento, causadas por espécies de Rhizoctonia, podem limitar a produção de mudas de eucalipto por estaquia. Apesar de sua importância, pouco se conhece sobre essas doenças. Assim, visando otimizar as estratégias de controle dessas doenças, nesse trabalho objetivou-se elucidar aspectos da dinâmica populacional de Rhizoctonia spp. no solo e em brotações, a fim de estabelecer, correlações com a incidência da doença, bem como determinar a distribuição do patógeno em jardim clonal de eucalipto. Conclui-se que há flutuação populacional de Rhizoctonia spp. em jardim clonal de eucalipto, sendo observado um padrão de distribuição espacial agregado do inóculo no solo. A dinâmica populacional de Rhizoctonia spp. foi correlacionada à temperatura, mas não à precipitação pluviométrica.

Leaf blight in shoots of clonal hedges and web blight of cuttings for rooting, caused by Rhizoctonia species, may be limiting to the production of eucalyptus seedlings by cuttings. Despite their importance, there have been few etiological and epidemiological studies of these diseases. To optimize disease management strategies, this research aimed to evaluate population dynamics of Rhizoctonia spp. in soil and eucalyptus cuttings to correlate with disease incidence, and to determine spatial distribution of Rhizoctonia spp. inoculum in a clonal nursery of eucalyptus cuttings. Population fluctuation of Rhizoctonia spp. was detected throughout the year. Pathogen distribution in soil was found to have an aggregated pattern. Temperature, but not rainfall, was correlated to population levels of Rhizoctonia spp in soil samples.

Avaliou-se a eficiência de Trichoderma longibranchiatum (UFV-1), de T. inhamatum (UFV-2 e UFV-3), compostos de casca e folhas de eucalipto contra Rhizoctonia spp., aplicados em solo de jardim clonal de eucalipto (Eucalyptus sp.). Em solos artificialmente infestados com Rhizoctonia spp., sob condições controladas, os antagonistas UFV-2 e UFV-3 apresentaram níveis elevados de supressividade, quando se aumentou a fonte alimentar na formulação, de 5 a 50 g de farelo de trigo por litro. No campo, o antagonista UFV-3 não teve efeito significativo na redução do inóculo de Rhizoctonia spp. Compostos de casca de eucalipto apresentaram diferentes graus de supressão a Rhizoctonia spp., dependendo da origem e do lote do composto. A incorporação de folhas de eucalipto ao solo favoreceu o aumento do inóculo de Rhizoctonia spp.

The effectiveness of Trichoderma longibranchiatum (UFV-1), T. inhamatum (UFV-2 and UFV-3), eucalyptus bark compost and leaves of eucalyptus was tested for the suppression of Rhizoctonia spp. in the soil of a clonal hedge of eucalyptus under controlled conditions. Soils artificially infested with Rhizoctonia spp., the antagonists UFV-2 and UFV-3 showed high levels of suppression of the pathogen when the feeding formulation rose from 5 to 50 g wheat bran per liter. However, in the field, the antagonist UFV-3 did not show a significant effect in reducing the inoculum of Rhizoctonia spp. Eucalypt us bark compost resulted in different levels of suppression of the pathogen depending on the compost pile and source. Adding eucalyptus leaves to the soil favored the inoculum of Rhizoctonia spp.