Eucalyptus Plantations In Brazil Research Articles

Evaluation of Palmistichus elaeisis Delvare & LaSalle (Hymenoptera: Eulophidae) as Parasitoid of the Sarsina violascens Herrich-Schaeffer (Lepidoptera: Lymantriidae)

This is the first report on the parasitoid Palmistichus elaeisis, genus Eulophidae, found in the field parasitizing pupae of defoliating eucalyptus. Lepidopterous pests occur in eucalyptus plantations in Brazil, reaching high population levels. Due to the complexity of pest control in eucalyptus forests, alternative control methods have been proposed, for instance biological control through use of parasitoids. Natural enemies play an important role in regulating host populations because their larvae feed on the eggs, larvae, pupae or adults of other insects. The parasitic Hymenoptera are important agents in biological control programs against forest pests, and may provide economic and environmental benefits. The generalist endoparasitoid Palmistichus elaeisis Delvare and LaSalle, 1993 (Hymenoptera: Eulophidae) can develop in its host’s pupae, which overcome the host’s physiology and can therefore be used for biological control of agricultural and forest pests. This study aimed to evaluate the impact of P. elaeisis as a pupal parasitoid of S. violascens in providing a potential alternative to chemical control of the pest and creation of an alternative host. The experiment was developed in the Laboratory for Biological Control of Forest Pests, Universidade Estadual Paulista

Real options valuation of forest plantation investments in Brazil

In this paper, we consider investments in eucalyptus plantations in Brazil. For such projects, we discuss real options valuation in the place conventional methods such as IRR or NPV, possibly with CAPM. Traditionally, real options valuation assumes complete markets and neglects market imperfections. Yet, market frictions, such as transaction costs, interest rate spreads, and restricted short positions, can play an important role. We extend real options valuation to allow incomplete and imperfect markets. The value is obtained as a competitive price, given markets of competing investment opportunities, such as real and financial assets. Under perfect and complete markets, such valuation method is consistent with conventional real options theory. Stochastic programming and standard software is used for valuation of eucalyptus plantations. We estimate the underlying interdependent diffusion processes of stock market, interest rates, exchange rates and pulpwood price, and derive novel expressions of stochastic integrals to be employed in scenario generation for discrete time stochastic programming.

Rapidly expanding host range for Puccinia psidii sensu lato in Australia

A rust affecting Myrtaceae was recently detected in New South Wales, Australia. Based on urediniospore morphology and host range, it was identified as Uredo rangelii, a taxon regarded as a member of the eucalyptus/guava rust (Puccinia psidii sensu lato) complex, although confusion currently surrounds its taxonomy. The exotic rust was given the common name of myrtle rust to distinguish it from eucalyptus/guava rust. The more recent discovery of teliospores in NSW that match those of P. psidii sensu stricto indicates the rust in Australia is a strain (with tonsured urediniospores) of P. psidii s.l. Outside Australia, P. psidii has a wide host range within Myrtaceae, being reported from 129 species in 33 genera, and is very damaging in South and Central America–including in eucalypt plantations in Brazil–the Caribbean and in Florida and Hawaii. To ascertain the potential threat to forestry in Australia posed by the introduced rust, we tested key forestry species, as well as key known hosts of eucalyptus/guava rust, in artificial inoculation experiments. We showed that several species of Eucalyptus are susceptible (viz. E. pilularis, E. cloeziana, E. agglomerata and E. grandis), as is Melaleuca quinquenervia. Observations during testing revealed a lengthened latent period (from inoculation until pustule formation and eruption) of four to five weeks during winter. Here we also report on observations on new hosts from surveys in NSW under the emergency response that followed the detection of the exotic rust, and surveys in NSW and Queensland following the cessation of the emergency response. In Australia, P. psidii s.l. has currently been found on 107 host species in 30 genera during surveys, including species in Angophora, Asteromyrtus, Austromyrtus, Backhousia, Callistemon, Chamelaucium, Choricarpia, Decaspermum, Eucalyptus, Eugenia, Gossia, Lenwebbia, Leptospermum, Lophomyrtus, Melaleuca, Metrosideros, Myrtus, Pilidiostigma, Rhodamnia, Rhodomyrtus, Ristantia, Stockwellia, Syncarpia, Syzygium, Tristania, Tristaniopsis, Ugni, Uromyrtus and Xanthostemon. Species under cultivation (in nurseries and gardens) that are severely affected include Gossiainophloia, Agonis flexuosa, Syzygium jambos and S. anisatum while species that are severely damaged in native bushland include Rhodamnia rubescens, Rhodomyrtus psidioides, Choricarpia leptopetala and Melaleuca quinquenervia.

Evaluation of Trichospilus diatraeae (Hymenoptera: Eulophidae) as parasitoid of the eucalyptus defoliator Euselasia eucerus (Lepidoptera: Riodinidae)

Lepidopteran pests have occurred in eucalyptus plantations in Brazil since 1948, reaching high population levels, reducing tree growth and causing considerable losses in wood production. The control of defoliating caterpillars in eucalyptus forests is complex, mainly due to the large extent of forest plantations and tree height, necessitating the aerial application of chemical or biological insecticides. Due to this complexity, alternative control methods have been proposed, for instance biological control through the use of parasitoids. Trichospilus diatraeae Cherian & Margabandhu, 1942 is a gregarious pupal parasitoid that preferentially attacks species of the order Lepidoptera. This is the first report of T. diatraeae parasitizing pupae of the eucalyptus defoliator Euselasia eucerus Hewitson in Brazil. This parasitoid offers new perspectives for the biological control programmes of this species in eucalyptus plantations in Brazil.

Morphological and molecular characterization of Pisolithus in soil under eucalyptus plantations in Brazil

Eighteen Pisolithus basidiomes were collected from Eucalyptus plantations in the state of Minas Gerais, Brazil. These basidiomes were characterized morphologically and molecularly. The basidiomes varied in shape, color and size. One of them was found underground, indicating a hypogeous fungus. The main morphological distinctive characteristic was spore ornamentation, which distinguished two groups. One group with short and erect spines was identified as Pisolithus microcarpus, and the other with long and curved spines as Pisolithus marmoratus, after analyzing the cladogram obtained by phylogenetic relationship based on internal transcribed spacer (ITS) regions of the nuclear ribosomal DNA of these isolates.

Effects of irrigation on water use and water use efficiency in two fast growing Eucalyptus plantations

Eucalyptus plantations occupy almost 20 million ha worldwide and exceed 3.7 million ha in Brazil alone. Improved genetics and silviculture have led to as much as a three-fold increase in productivity in Eucalyptus plantations in Brazil and the large land area occupied by these highly productive ecosystems raises concern over their effect on local water supplies. As part of the Brazil Potential Productivity Project, we measured water use of Eucalyptus grandis × urophylla clones in rainfed and irrigated stands in two plantations differing in productivity. The Aracruz (lower productivity) site is located in the state of Espirito Santo and the Veracel (higher productivity) site in Bahia state. At each plantation, we measured stand water use using homemade sap flow sensors and a calibration curve using the clones and probes we utilized in the study. We also quantified changes in growth, leaf area and water use efficiency (the amount of wood produced per unit of water transpired). Measurements were conducted for 1 year during 2005 at Aracruz and from August through December 2005 at Veracel. Transpiration at both sites was high compared to other studies but annual estimates at Aracruz for the rainfed treatment compared well with a process model calibrated for the Aracruz site (within 10%). Annual water use at Aracruz was 1394 mm in rainfed treatments versus 1779 mm in irrigated treatments and accounted for approximately 67% and 58% of annual precipitation and irrigation inputs respectively. Increased water use in the irrigated stands at Aracruz was associated with higher sapwood area, leaf area index and transpiration per unit leaf area but there was no difference in the response of canopy conductance with air saturation deficit between treatments. Water use efficiency at the Aracruz site was also not influenced by irrigation and was similar to the rainfed treatment. During the period of overlapping measurements, the response to irrigation treatments at the more productive Veracel site was similar to Aracruz. Stand water use at the Veracel site totaled 975 mm and 1102 mm in rainfed and irrigated treatments during the 5-month measurement period respectively. Irrigated stands at Veracel also had higher leaf area with no difference in the response of canopy conductance with air saturation deficit between treatments. Water use efficiency was also unaffected by irrigation at Veracel. Results from this and other studies suggest that improved resource availability does not negatively impact water use efficiency but increased productivity of these plantations is associated with higher water use and should be given consideration during plantation management decision making processes aimed at increasing productivity.

Alocação de nutrientes em plantios de eucalipto no Brasil

Práticas de manejo florestal podem alterar a exportação de nutrientes do sítio. Este trabalho teve por objetivo estimar o conteúdo de nutrientes em árvores de eucalipto, em diferentes regiões do Brasil. Avaliou-se a influência de algumas características climáticas na produção e no conteúdo de nutrientes na biomassa, utilizando-se o banco de dados do Programa de Pesquisa em Solos e Nutrição de Eucalipto do Departamento de Solos - UFV. As características climáticas foram um importante componente dos modelos. A produção de biomassa e o conteúdo de nutrientes foram positivamente relacionados entre si e ambos foram menores nas regiões com menor disponibilidade de água. As estimativas apontaram que até à idade de 4,5 anos pós-plantio acumulam-se as maiores proporções de nutrientes (68 % do N, 69 % do P, 67 % do K, 63 % do Ca e 68 % do Mg) para a idade de corte de 6,5 anos. Isto indica que, após 4,5 anos, o potencial de resposta à aplicação de fertilizantes é menor. O conteúdo estimado de nutrientes acumulados na copa e na casca representou 65, 70, 64, 79 e 79 %, de N, P, K, Ca e Mg, respectivamente, até 6,5 anos de idade. Assim, a colheita apenas do lenho representa expressiva redução na exportação desses nutrientes proporcionando maior sustentabilidade da produção nas plantações de eucalipto.

Estimativa de biomassa de plantios de eucalipto no Brasil

O objetivo deste trabalho foi estimar a produção de biomassa de eucalipto, para diferentes regiões do Brasil. Foi avaliado o efeito de características climáticas sobre a produtividade de eucalipto utilizando-se o banco de dados do Programa de Pesquisa em Solos e Nutrição de Eucalipto do Departamento de Solos - UFV. Características climáticas e idade do povoamento foram importantes para obtenção do modelo. Houve variação na produção estimada de biomassa entre regiões, sendo a maior produtividade três vezes superior à menor. A produção de biomassa foi menor nas regiões com menor disponibilidade de água. A proporção de copa em relação ao tronco reduziu com a idade da plantação, de maneira acentuada até à idade de 3,6 anos, e de maneira mais lenta a partir desta idade.

New record ofTrichospilus diatraeae as a parasitoid of the eucalypt defoliatorThyrinteina arnobia in Brazil

This is the first report ofTrichospilus diatraeae Cherian & Margabandhu, 1942 (Hymenoptera: Eulophidae) parasitizing pupae of the eucalypt defoliatorThyrinteina arnobia (Stoll, 1782) (Lepidoptera: Geometridae). Parasitized pupae of this insect were collected in the field in Brazil. In view of this finding, the potential of this parasitoid for biological control ofT. arnobia in eucalypt plantations in Brazil should be investigated.

Growth and water balance of Eucalyptus grandis hybrid plantations in Brazil during a rotation for pulp production

The water balance and growth of Eucalyptus grandis hybrid plantations in Brazil are presented based on 6 years of intensive catchment hydrology, physiological and forest growth surveying, and modelling. The results show a balance between water supply by precipitation and output through evapotranspiration (considered as canopy interception, soil evaporation and trees transpiration) and runoff. The annual average precipitation was 1147 mm and average evapotranspiration was 1092 mm. The runoff was only 3% of the precipitation, because of high soil infiltration and the flat topography where the trees are planted. Evapotranspiration rates varied from 781 mm to 1334 mm during the years of the study and are strongly influenced by variations in annual precipitation and leaf area index. When the precipitation was close to the regional mean annual precipitation of 1350 mm there was enough water to supply the demands of the trees and produce some runoff. Biomass production was high and the peak annual growth rate was 95 m 3 ha −1 year −1. The UAPE model [Soares, J.V., Almeida, A.C., 2001. Modeling the water balance and soil water fluxes in a fast-growing Eucalyptus plantation in Brazil. J. Hydrol. 253, 130–147] was used to estimate the water balance and the widely used 3-PG model [Landsberg, J.J., Waring, R.H., 1997. A generalised model of forest productivity using simplified concepts of radiation-use efficiency, carbon balance and partitioning. For. Ecol. Manage. 95, 209–228] was used to estimate forest growth and water-use efficiency.

FIRST RECORD OF Trichogramma pratissolii IN Eucalyptus spp. PLANTATION IN THE STATE OF MINAS GERAIS – BRAZIL

Cardboards with Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs were fastened to eucalyptus plants in the Municipality of Paraopeba, State of Minas Gerais, Brazil aiming to collect egg parasitoids that naturally occur in this area. All individuals of egg parasitoids collected were identified as Trichogramma pratissolii Querino and Zucchi (Hymenoptera: Trichogrammatidae) and it represents the first report of this species in the Minas Gerais State and also in Eucalyptus plantations in Brazil.

Improving phosphorus availability from patos phosphate rock for Eucalyptus: a study with 32P radiotracer

Eucalyptus plantation in Brazil is generally set on low fertility soils, therefore phosphorus (P) fertilization is mandatory and increases the cost of plantation operation. Using species that more efficiently uptake phosphorus from less soluble sources is an interesting option. However, little is known about eucalyptus regarding its ability of using less soluble forms of phosphorus. The use of P by eucalyptus (E. urophylla, E. grandis, and E. urophylla <FONT FACE=Symbol>´</FONT> E. grandis) was studied in greenhouse using a loamy-textured, hipodystrophic Typic Haplustox from the Cerrado region, and 32P isotopic method. The P sources tested were triple superphosphate (TSP), phosphate rock (PR) and the triple superphosphate mixed with PR (TSP+PR). The effectiveness of P sources in terms of increasing dry matter yield was TSP = (TSP + PR) > PR, and the P uptake followed the order (TSP + PR) > TSP > PR for both species plus the hybrid. The increase in P uptake from PR due to TSP influence was 217.3% for E. urophylla, 235.7% for E. grandis, and 28.7% for E. urophylla <FONT FACE=Symbol>´</FONT> E. grandis, indicating an enhancement effect of TSP on the effectiveness of PR. The hybrid E. urophylla <FONT FACE=Symbol>´</FONT> E. grandis was the most efficient genotype on P soil use and E. grandis most exigent in P fertilizer.

Nitrogênio, carbono e atividade da biomassa microbiana do solo em plantações de eucalipto

Grande parte das plantações de eucalipto no Brasil situa-se em solos de baixa fertilidade, para os quais a técnica de fertilização e o processo de ciclagem de nutrientes são fundamentais para elevar e manter a produção florestal. Os ganhos de produtividade dessas plantações em resposta à aplicação de N têm sido relativamente baixos, o que indica que o solo tem sido capaz de suprir boa parte da demanda deste nutriente para as plantas. O N da biomassa microbiana é tido como uma fração facilmente disponível, mas pouco se sabe sobre como fatores bióticos e abióticos afetam a sua dinâmica em plantações de eucalipto no Brasil. Desse modo, o objetivo deste trabalho foi avaliar a variação do N (NBM) e C (CBM) da biomassa microbiana do solo e de outras características com elas relacionadas em plantações de eucalipto com sete anos de idade, cultivadas em várias condições edafoclimáticas do sudeste brasileiro. Amostragens do solo foram realizadas durante quatro épocas, de março a novembro de 1995. O teor de NBM variou de 9,17 a 103,71 µg g-1 solo, sendo significativamente influenciado pela época de amostragem. Essa variação foi explicada pela combinação da precipitação pluviométrica com o teor de C orgânico ou N total. O teor de argila dos solos estudados foi outra característica de grande importância nessa variação. Dentre outras características avaliadas, verificou-se que a forma de N mineral predominante foi N-NH4+ e que os teores de C orgânico e do CBM (carbono da biomassa microbiana) variaram de 2,78 a 12,32 g kg-1 e de 43,39 a 401,06 µg g-1 solo, respectivamente. A RA (respiração acumulada do solo) foi de 14,57 a 79,42 µg g-1 solo e o qCO2 (quociente metabólico) de 862 a 8026 µg g-1 h-1 . O CBM foi também afetado significativamente pela época de amostragem, ao contrário dos teores de C orgânico e N total. As regressões lineares simples do teor de N-NO3-, C orgânico, N total, CBM e NBM com o teor de argila permitiram um modelo preditivo que explicasse a variação destes atributos nos diferentes municípios. A umidade atual do solo explicou 87% da variação dos teores de N-NO3- e de N total; em torno de 71% do C orgânico e de 48 e 55% da variação do CBM e NBM, respectivamente. As regressões simples do N-NO3- com o CBM ou NBM apresentaram baixa capacidade preditiva, porém, quando conjugadas com os teores de C orgânico ou N total, por meio de regressão linear múltipla, aumentaram a capacidade preditiva da mineralização do N.

Aspectos biológicos de Thyrinteina arnobia (Lep.: Geometriadae) provenientes de lagartas criadas em folhas de Eucalyptus cloeziana ou de Psidium guajava sob condições de campo

Os plantios de Eucalyptus no Brasil podem sofrer danos por espécies nativas de insetos de diversas ordens, como Orthoptera, Coleoptera e Lepidoptera. Esses insetos podem alimentar-se tanto de mirtáceas brasileiras como goiabeira, gabirobeira, jabuticabeira, entre outras, como de espécies do gênero Eucalyptus. Entre os desfolhadores, destaca-se Thyrinteina arnobia (Stoll) (Lepidoptera: Geometridae) como o mais daninho dessa ordem para a eucaliptocultura brasileira. Este trabalho teve por objetivo avaliar aspectos biológicos de adultos de T. arnobia provenientes de lagartas alimentadas com plantas de eucalipto e, ou, goiabeira. Adultos deste inseto criados em folhas de eucalipto e, ou, de goiabeira apresentaram diferenças significativas para a maioria dos aspectos biológicos avaliados, exceto para a duração dos períodos de préoviposição, de oviposição e razão sexual. Assim, insetos herbívoros que vivem em hospedeiros filogeneticamente próximos ao eucalipto são capazes de causar danos consideráveis em reflorestamentos com espécies desse grupo, o que provavelmente ocorre pelo fato de elas estarem ainda em processo de adaptação a essa praga que atacaria o eucalipto, por estar fugindo da pressão exercida por barreiras físicas e químicas existentes nas mirtáceas nativas brasileiras.

Produção e estado nutricional de povoamentos de Eucalyptus grandis, em segunda rotação, em resposta à adubação potássica

A condução de brotação de cepas é uma técnica corriqueira nas plantações de eucalipto no Brasil. Contudo, a queda de produtividade da primeira para a segunda rotação tem sido freqüentemente observada, e a deficiência de nutrientes minerais é uma das possíveis causas deste fato. O objetivo deste estudo foi avaliar o efeito residual de doses de K sobre o estado nutricional, o balanço de K e a produção de Eucalyptus grandis, em segunda rotação, assim como as quantidades de N, P, K, Ca e Mg acumuladas na copa e no tronco. Doses de 30, 60, 120 e 240 kg/ha de K2O, na forma de KCl, foram aplicadas a lanço em toda a área e incorporadas ao solo antes do plantio. Incluiu-se, ainda, a parcela sem aplicação de K. Na primeira rotação as árvores foram cortadas aos 78 meses. Em seguida, fez-se a condução de um broto por cepa. Aos 80 meses após o primeiro corte, ou seja, já na segunda rotação, foram avaliados o volume do tronco, a produção de matéria seca e o conteúdo de nutrientes na árvore e na manta orgânica e os teores de nutrientes no solo. A maior dose de K, aplicada na implantação do povoamento, causou aumento da ordem de 54% no volume e na matéria seca dos troncos das árvores na segunda rotação, em comparação com o tratamento sem adubação. Nessas condições, a diferença no acúmulo de N, P, Ca e Mg nas árvores foi, em média, de 69%. Da primeira para a segunda rotação houve decréscimo médio de 52% na produtividade, atribuído à exportação de nutrientes, em especial de K, na rotação anterior, ocasionando a redução na fertilidade do solo.

Modeling the water balance and soil water fluxes in a fast growing Eucalyptus plantation in Brazil

A five-layered water balance model, with water movement between layers along hydraulic gradients, was developed and parameterized for a eucalypt plantation (Eucalyptus grandis Hill ex. Maiden hybrids) in Brazil. Available soil water controls stomatal conductance and hence transpiration, which is calculated by the Penman–Monteith equation. The model accounts for changes in the depths of the water table. Calculations are supported by measurements: the test period was from October 1995 to September 1996 in a 9-year-old plantation in an experimental catchment in eastern Brazil. Total transpiration for the year was 1116mm, with 151mm intercepted and re-evaporated and another 78mm soil surface evaporation, giving evapotranspiration of 1345mm compared to rainfall of 1396mm. The water balance was closed by net flow below the root zone of about 25mm and an increase in water storage (in the first layer) of 24mm. The model also estimated a transpiration deficit (difference between the potential and current transpiration) of 125mm for the period. Upward flux from the water table was around 82mm and piezometric measurements showed 2.5m recession of the water table for the same period. The upward flux into the root zone was about 1mm day−1 at the end of a long dry season; that kept the water storage in that zone to about 15% of capacity and helped prevent complete stomatal closure.Comparison between estimated water storage and measurements confirmed that this model is a very promising tool for calculating water use by plantations. It can also provide water balance information and information about stomatal conductance for growth prediction models.

Genetic variability of Pisolithus isolates associated with native hosts and exotic eucalyptus in the western Mediterranean region.

• Genetic diversity and host specificity of Pisolithus is reported here in exotic (Eucalyptus) and native hosts in the western Mediterranean region. • Polymorphism in the internal transcribed spacer (ITS) sequences of the nuclear rDNA of Pisolithus was analysed. Sequences for 17 isolates associated with native Mediterranean hosts and Eucalyptus were compared with those in the GenBank DNA database using distance and parsimony methods. • Bootstrap analysis showed clustering of all Pisolithus isolates associated with Mediterranean hosts. The ITS sequences suggest the occurrence of several ecological species adapted to exploit different soil types (basic, acid and clayey slate-derived soils), with specificity for particular indigenous hosts. Isolates from eucalypt plantations in Brazil, Kenya and the Mediterranean grouped together with eucalypt-associated Australian isolates. Transfer to native hosts did not occur; the host specificity range of these exotic strains might prevent out-competition and interbreeding with local species. • Pisolithus spp. in eucalypt plantations in the Mediterranean basin are of Australian origin; the co-introduction of the ectomycorrhizal fungi might explain the success of these exotic forest plantations.

Relationships between nursery practices and field performance for Eucalyptus plantations in Brazil

The 3.5 million ha of Eucalyptus plantations in Brazil support many domestic and industrial activities. In the pulpwood sector, forest productivity has increased from 12 to 40 m3 ha−1 year−1 through breeding and silviculturalpractices. Nurseries have fostered thisevolution with changes in container/substratetypes, propagation methods and specificinfrastructure for each plant growth phase.Eucalyptus plants are mainly produced bycuttings, using rigid tube containers filledwith vermiculite-organic compound substrates.Stock quality is based on morphologicalcharacteristics of the plants, andenvironmental conditions are highly significantfor plant performance. Performance is dependenton physiological short-term effects related tosurvival and long-term effects of genotype/rootmorphology related to tree development. Currentsilvicultural trends are reducing establishmentcosts but increasing the risk of using lowquality plants. The development of fieldperformance models and nursery physiologicaltests is recommended for Eucalyptusplantations in Brazil. Improved experimentaldesigns are needed to capture the interactionbetween plant quality and field performance.

Effect of plantation age on diversity and population fluctuation of Lepidoptera collected in Eucalyptus plantations in Brazil

A faunistic survey of Lepidoptera associated with eucalyptus was carried out from June 1989 to June 1994 in a plantation at the Vale do Rio Doce Region, State of Minas Gerais, Brazil. Insects were collected every fifteen days with five light traps and divided in primary, secondary and non-pests of eucalyptus as well as a group of nonidentified morphospecies. Twelve primary pests with 5823 individuals; 17 secondary pests with 2757 individuals; 148 non-pests with 8856 individuals and 1179 unidentified morphospecies with 11,834 individuals were collected. The most abundant primary pest species were Stenalcidia grosica and Glena unipennaria (Lepidoptera: Geometridae) while Eacles imperialis magnifica and Automeris illustris (Lepidoptera: Saturniidae) and Idalus admirabilis (Lepidoptera: Arctiidae) were the most abundant secondary species. Differences in numbers of individuals trapped were significantly higher between locations of light traps than between years. There were significantly more species in the last years of this study, but the number of specimens was similar for all years. These results indicate a high environmental stability and suggest that this region is one of the most suitable areas for Eucalyptus plantation in Brazil.

Effects of environmental heterogeneity on Lepidoptera and Hymenoptera populations in Eucalyptus plantations in Brazil

For 5 months, insects from the Lepidoptera and Hymenoptera orders were collected at five sites: in the interior of a Brazilian native forest, in the zone of contact between the native forest and a Eucalyptus plantation, and in three sites within the Eucalyptus plantation, at 200, 400 and 600 m from the edge of the native forest. Lepidoptera were collected with light traps and divided into three groups in relation to the damage they cause to Eucalyptus: primary pests, secondary pests, and other abundant but non-pest species. Hymenoptera were collected with Malaise traps and categorized as predators, egg parasitoids or larval parasitoids. In general, the heterogeneity hypothesis was supported: total lepidopteran abundance was higher and total natural enemy abundance was lower in the Eucalyptus plantation than within the native forest or at the edge of the native forest and the Eucalyptus plantation. Negative correlations were found between the abundance of Lepidoptera and that of egg parasitoids and larval parasitoids. No significant differences in the abundance of lepidopteran pests and hymenopteran natural enemies were found among the three sites within the Eucalyptus plantation. Plantations of Eucalyptus intercalated with native vegetation could reduce outbreaks of lepidopteran pests by increasing numbers of Hymenoptera natural enemies of these pests.