Advances in submerged liquid fermentation and formulation of entomopathogenic fungi.

Entomopathogenic fungi (EPF) can be defined as beneficial multifunctional eukaryotic microorganisms that display pivotal ecological services in pest management, with some species possessing the special ability to establish mutualistic relationships with plants. Mass production of these fungi is critical to support affordable widespread commercialization and worldwide field application. Among the mass production methods explored mainly by industry, submerged liquid fermentation is a robust and versatile technology that allows the formation of different types of propagules designated for various applications in pest control. Many hypocrealean EPF are easily culturable on artificial substrates by producing single-celled structures (hyphal bodies, blastospores, and submerged conidia) or multicellular structures (mycelium and microsclerotia). Less frequently, some EPF may form environmentally resistant chlamydospores, but these structures have almost always been overlooked. A continued research pipeline encompassing screening fungal strains, media optimization, and proper formulation techniques aligned with the understanding of molecular cues involved in the formation and storage stability of these propagules is imperative to unlock the full potential and to fine-tune the development of robust and effective biocontrol agents against arthropod pests and vectors of diseases. Finally, we envision a bright future for the submerged liquid fermentation technology to supplement or replace the traditional solid substrate fermentation method for the mass production of many important EPF. KEY POINTS: • Submerged liquid fermentation (SLF) allows precise control of nutritional and environmental factors • SLF provides a scalable, robust, and cost-effective platform for mycopesticide production • Enhancing formulation, shelf life, and field efficacy of submerged propagules remain crucial • Understanding the molecular mechanisms behind submerged propagule formation is key to advancing SLF technology.

Isolation and characterization of a native strain of the entomopathogenic fungus Beauveria bassiana for the control of the palm weevil Dynamis borassi (Coleoptera: Curculionidae) in the neotropics.

This study aimed to isolate and characterize a native strain of Beauveria bassiana, coded as Bv065, showcasing its potential as a biological control agent targeting the palm weevil Dynamis borassi. Originating from a naturally infected D. borassi specimen collected in southwestern Colombia, the fungus underwent molecular identification and was identified as B. bassiana, exhibiting high sequence similarity with known reference strains. The physiological characterization revealed that Bv065 thrived within a temperature range of 25 to 30 °C and a pH range of 6 to 9. Moreover, the key carbon sources that allow optimal growth of the strain were identified through metabolic profiling, including sucrose, D-mannose, and γ-amino-butyric acid. These findings offer strategic insights for scalability and formulation methodologies. Additionally, enzymatic analyses unveiled robust protease activity within Bv065, crucial for catalysing insect cuticle degradation and facilitating host penetration, thus accentuating its entomopathogenic potential. Subsequent evaluations exposed Bv065's pathogenicity against D. borassi, causing significant mortality within nine days of exposure, albeit exhibiting limited effectiveness against Rhynchophorus palmarum. This study underscores the importance of understanding optimal growth conditions and metabolic preferences of B. bassiana strains for developing effective biopesticides. The findings suggest Bv065 as a promising candidate for integrated pest management strategies in neotropical regions, particularly for controlling palm weevil infestations in coconut and peach palm cultivation. Future research avenues include refining mass production methodologies, formulating novel delivery systems, and conducting comprehensive field efficacy trials to unlock the full potential of Bv065 in fostering sustainable pest management practices. Overall, this study contributes to the growing body of knowledge on entomopathogenic fungi and their pivotal role in biological control, offering nuanced perspectives on eco-friendly alternatives to conventional insecticidal interventions.

Optimization of In Vivo Production of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV).

Insect viruses have been used to protect crops and forests worldwide for decades. Among insect viruses, isolates of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) have proven potential for the control of Spodoptera frugiperda (J. E. Smith) (FAW) (Lepidoptera: Noctuidae), a pest of many economically essential crops across several continents. Mass production of SfMNPV depends on an in vivo system using host insect rearing. However, many factors can limit its production, including abiotic factors and host characteristics, such as the stage of development and an antagonist intraspecific interaction. Thus, to improve in vivo production, we verified the most suitable larval age to inoculate the virus and the influence of incubation temperature on viral production. Subsequently, cannibal behavior was verified in FAW larvae reared at different densities, while reproducing the conditions of the best treatments. The highest viral yield occurred when FAW larvae were inoculated at 10 and 8 days old and incubated at 22 °C and 25 °C, respectively. Nonetheless, survival (lethal period in days) and cannibal behavior were positively influenced by larval development, which potentially increases the load of contamination and requires larval individualization for these production conditions. In contrast, 4-day-old larvae, which were inoculated and incubated at 31 °C, also demonstrated high viral production, with lower rates of cannibalism and death on the same day, thereby showing potential. The information presented in this study is useful for the optimization of the in vivo production systems of SfMNPV.

Spark Plasma Sintering of Aluminum Nanocomposite Powders: Recent Strategy to Translate from Lab-Scale to Mass Production.

The aim of this paper focuses on presenting a recent study that describes the fundamental steps needed to effectively scale-up from lab to mass production parts produced from Al powders reinforced with 0.5 wt% of industrial multiwalled carbon nanotubes (MWCNTs), with mechanical and electrical conductivity properties higher that those measured at the lab scale. The produced material samples were produced via a Spark Plasma Sintering (SPS) process using nanocomposite aluminum powders elaborated with a planetary ball-mill at the lab scale, and high-volume attrition milling equipment in combination with controlled atmosphere sinter hardening furnace equipment, which were used to consolidate the material at the industrial level. Surprisingly, the electrical conductivity and mechanical properties of the samples produced with the reinforced nanocomposite Al powders were made with mass production equipment and were similar or higher than those samples fabricated using metallic powders prepared with ball-mill lab equipment. Experimental measurements show that the hardness and the electrical conductivity properties of the samples fabricated with the mass production Al powders are 48% and 7.5% higher than those of the produced lab samples. This paper elucidates the steps that one needs to follow during the mass production process of reinforced aluminum powders to improve the physical properties of metallic samples consolidated via the SPS process.

Advances in the biological control of phytoparasitic nematodes via the use of nematophagous fungi.

Agricultural production is one of most important activities for food supply and demand, that provides a source of raw materials, and generates commercial opportunities for other industries around the world. It may be both positively and negatively affected by climatic and biological factors. Negative biological factors are those caused by viruses, bacteria, or parasites. Given the serious problems posed by phytoparasitic nematodes for farmers, causing crop losses globally every year, the agrochemical industry has developed compounds with the capacity to inhibit their development; however, they can cause the death of other beneficial organisms and their lixiviation can contaminate the water table. On the other hand, the positive biological factors are found in biotechnology, the scientific discipline that develops products, such as nematophagous fungi (of which Purpureocillium lilacinum and Pochonia chlamydosporia have the greatest potential), for the control of pests and/or diseases. The present review focuses on the importance of nematophagous fungi, particularly sedentary endoparasitic nematodes, their research on the development of biological control agents, the mass production of fungi Purpureocillium lilacinum and Pochonia chlamydosporia, and their limited commercialization due to the lack of rigorous methods that enable the anticipation of complex interactions between plant and phytopathogenic agents.

Optimization of Large-Scale Production of Chrysodeixis includens nucleopolyhedrovirus for Its Use as a Biopesticide.

The baculovirus Chrysodeixis includens nucleopolyhedrovirus (ChinNPV) is pathogenic to Chrysodeixis includens (Walker) (Lepidoptera: Noctuidae) larvae, known as soybean looper, which is an important pest of soybean and bean. In this study, some parameters were tested to overcome the difficulties in the in vivo production of ChinNPV aiming to increase its use as a biopesticide. First, different combinations of larval instars (3rd and 4th instars), larval incubation temperatures (23 °C and 26 °C), and rearing densities (individually and 10 larvae/cup) were compared for larval weight and the production of occlusion bodies (OBs). A positive correlation (p< 0.001) was observed for OB production and larval weight. Fourth instar larvae produced more OBs than third instar larvae (p<0.05); however, no significant differences in OBs/larva (p>0.05) were observed for larvae kept in groups or individually. Therefore, a second assay was performed using fourth instar larvae incubated at 26 °C and two larval densities (10 larvae/cup and 40 larvae/cup). The losses of insects and OB production were evaluated as well as the influence of storage temperatures post-mortem (-20 °C, 4 °C, and 15 °C) in the OB yield. As expected, insect losses due to cannibalism or microbial contamination were greater (p<0.05) with the increase in larval density, although no difference was observed in OBs/larva (p>0.05). In addition, the storage temperature post-mortem did not influence the OB yield (p>0.05). The average production of ChinNPV OBs was 3×1010 OBs/40 larvae cup. The results demonstrate the viability of rearing C. includens in groups to enhance the mass production and reduce virus production costs.

A nonconventional two-stage fermentation system for the production of aerial conidia of entomopathogenic fungi utilizing surface tension.

AIM: To describe a new approach in which production of conidia of an entomopathogenic fungus takes place on the surface of an unstirred shallow liquid culture kept in nonabsorbent wells distributed in plastic sheets resembling a honeycomb. METHODS AND RESULTS: First, liquid incubation time and medium composition for production of Beauveria bassiana aerial conidia were optimized. Wells inoculated with Sabouraud dextrose yeast extract produced 2·2 × 108 conidia per cm2 of liquid surface following 5 days of incubation. Finally, tests were carried out in a prototype comprised of stacked plastic sheets in a cylindrical container. Conidia production on liquid culture surface varied from 1·2 to 1·6 × 109 conidia per ml of fermented broth. Germination rates and insect activity towards Tenebrio molitor larvae were not negatively affected when compared to conidia produced on solid medium. CONCLUSIONS: The two-stage fermentation process here described, based on a simple nonabsorbent inert support, has potential for the application in the production of aerial conidia of B. bassiana and other fungi. SIGNIFICANCE AND IMPACT OF THE STUDY: Aerial conidia are the most extensive propagule type used in commercial mycopesticides, traditionally produced by solid-state fermentation (SSF). The industrial applications and other important benefits of the two-stage fermentation process here described may overcome some hurdles inherent to SSF aiming for the production of aerial conidia. Additionally, production consistency is increased by the use of chemically defined medium, and the better control of the environmental conditions could allow for more reproducible industrial batches.

Male irradiation affects female remating behavior in Anastrepha serpentina (Diptera: Tephritidae).

Female remating in target pest species can affect the efficacy of control methods such as the Sterile Insect Technique (SIT) but very little is known about the postcopulatory mating behavior of these pests. In this study, we investigated the remating behavior of female Anastrepha serpentina (Diptera: Tephritidae), an oligophagous pest of Sapotaceae. First, we tested how long the sexual refractory period of females lasted after an initial mating. Second, we tested the effect of male and female sterility, female ovipositing opportunities and male density on female propensity to remate. Lastly, we tested if the amount of sperm stored by females was correlated to the likelihood of females to remate. We found that receptivity of mass-reared A. serpentina females had a bimodal response, with up to 16% of mass-reared A. serpentina females remating five days after the initial copulation, decreasing to 2% at 10 and 15 days and increasing to 13% after 20 days. Compared to fertile males, sterile males were less likely to mate and less likely to inhibit females from remating. Copula duration of sterile males was shorter compared to fertile males. Remating females were less likely to mate with a sterile male as a second mate. Sterile females were less likely to mate or remate compared to fertile females. Opportunity to oviposit and male density had no effect on female remating probability. Sperm numbers were not correlated with female likelihood to remate. Information on the post-copulatory behavior of mass-reared A. serpentina will aid fruit fly managers in improving the quality of sterile males. We discuss our results in terms of the differences this species presents in female remating behavior compared to other tephritids.

Biological control of banana black Sigatoka disease with Trichoderma / Controle biológico da Sigatoka-negra da bananeira com Trichoderma

Black Sigatoka disease caused by Mycosphaerella fijiensis is the most severe banana disease worldwide. The pathogen is in an invasive phase in Brazil and is already present in most States of the country. The potential of 29 isolates of Trichoderma spp. was studied for the control of black Sigatoka disease under field conditions. Four isolates were able to significantly reduce disease severity and were further tested in a second field experiment. Isolate 2.047 showed the best results in both field experiments and was selected for fungicide sensitivity tests and mass production. This isolate was identified as Trichoderma atroviride by sequencing fragments of the ITS region of the rDNA and tef-1α of the RNA polymerase. Trichoderma atroviride was as effective as the fungicide Azoxystrobin, which is recommended for controlling black Sigatoka. This biocontrol agent has potential to control the disease and may be scaled-up for field applications on rice-based solid fermentation.

A Sigatoka-negra causada por Mycosphaerella fijiensis é a doença mais destrutiva da bananeira em termos mundiais. O patógeno está em uma fase invasiva no Brasil e já se encontra distribuído na maior parte dos Estados do país. O potencial de 29 isolados de Trichoderma spp. para o controle da Sigatoka-negra foi estudado sob condições de campo. Quatro isolados foram capazes de reduzir significativamente a severidade da doença e foram selecionados para um segundo experimento de campo. O isolado 2.047 apresentou os melhores resultados e foi utilizado em testes de sensibilidade a fungicidas e produção massal. Esse isolado foi identificado como Trichoderma atroviride por meio do sequenciamento de fragmentos da regiões ITS do rDNA e tef-1α da RNA polymerase. Trichoderma atroviride foi tão efetivo no controle da Sigatoka-negra quanto o fungicida Azoxystrobin, que é recomendado para o controle da doença. O agente de controle biológico tem potencial para o controle da Sigatoka-negra e pode ser produzido em massa em arroz autoclavado para aplicações no campo.

Biological control of banana black Sigatoka disease with Trichoderma / Controle biológico da Sigatoka-negra da bananeira com Trichoderma

Black Sigatoka disease caused by Mycosphaerella fijiensis is the most severe banana disease worldwide. The pathogen is in an invasive phase in Brazil and is already present in most States of the country. The potential of 29 isolates of Trichoderma spp. was studied for the control of black Sigatoka disease under field conditions. Four isolates were able to significantly reduce disease severity and were further tested in a second field experiment. Isolate 2.047 showed the best results in both field experiments and was selected for fungicide sensitivity tests and mass production. This isolate was identified as Trichoderma atroviride by sequencing fragments of the ITS region of the rDNA and tef-1 of the RNA polymerase. Trichoderma atroviride was as effective as the fungicide Azoxystrobin, which is recommended for controlling black Sigatoka. This biocontrol agent has potential to control the disease and may be scaled-up for field applications on rice-based solid fermentation.(AU)

A Sigatoka-negra causada por Mycosphaerella fijiensis é a doença mais destrutiva da bananeira em termos mundiais. O patógeno está em uma fase invasiva no Brasil e já se encontra distribuído na maior parte dos Estados do país. O potencial de 29 isolados de Trichoderma spp. para o controle da Sigatoka-negra foi estudado sob condições de campo. Quatro isolados foram capazes de reduzir significativamente a severidade da doença e foram selecionados para um segundo experimento de campo. O isolado 2.047 apresentou os melhores resultados e foi utilizado em testes de sensibilidade a fungicidas e produção massal. Esse isolado foi identificado como Trichoderma atroviride por meio do sequenciamento de fragmentos da regiões ITS do rDNA e tef-1 da RNA polymerase. Trichoderma atroviride foi tão efetivo no controle da Sigatoka-negra quanto o fungicida Azoxystrobin, que é recomendado para o controle da doença. O agente de controle biológico tem potencial para o controle da Sigatoka-negra e pode ser produzido em massa em arroz autoclavado para aplicações no campo.(AU)

New method for rearing Spodoptera frugiperda in laboratory shows that larval cannibalism is not obligatory

New method for rearing Spodoptera frugiperda in laboratory shows that larval cannibalism is not obligatory. Here we show, for the first time, that larvae of the fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera, Noctuidae), can be successfully reared in a cohort-based manner with virtually no cannibalism. FAW larvae were reared since the second instar to pupation in rectangular plastic containers containing 40 individuals with a surprisingly ca. 90% larval survivorship. Adult females from the cohort-based method showed fecundity similar to that already reported on literature for larvae reared individually, and fertility higher than 99%, with the advantage of combining economy of time, space and material resources. These findings suggest that the factors affecting cannibalism of FAW larvae in laboratory rearings need to be reevaluated, whilst the new technique also show potential to increase the efficiency of both small and mass FAW rearings.

Crescimento e produtividade da abobrinha italiana: efeito da concentração iônica da solução nutritiva / Growth and yield of summer squash: effect of the ionic concentration of nutrient solution

Com o objetivo de avaliar o efeito de diferentes concentrações iônicas da solução nutritiva sobre o crescimento e a produtividade da abobrinha italiana cultivada em substrato de casca de arroz in naturacom recirculação dos lixiviados, foram realizados dois experimentos em duas épocas de cultivo: primavera-verão de 2005 e verão-outono de 2006, em Pelotas, RS. Quatro concentrações iônicas da solução nutritiva (com base na condutividade elétrica - CE) foram estudadas: 1,3; 1,7; 2,1 e 4,2 dS m-1. Determinou-se o crescimento da cultura, por meio da quantificação da produção e da partição de massa seca acumulada ao final dos ciclos de cultivo pelos diferentes órgãos aéreos da planta (folha, caule e frutos), e a produtividade. Os resultados obtidos nos experimentos indicam que concentrações iônicas iguais ou inferiores a 1,7 dS m-1 são limitantes para o adequado crescimento e produtividade da cultura. O efeito da alta concentração iônica da solução nutritiva (acima de 2,1 dS m-1) sobre a produção e a partição de massa seca varia de acordo com ciclo de cultivo. A menor disponibilidade de radiação solar no período de verão-outono minimiza os efeitos das diferentes concentrações da solução nutritiva sobre a produção e a partição de massa seca para os frutos, bem como sobre a produtividade. Os frutos representaram de 28 a 52% da massa seca total da parte aérea das plantas. Apenas na solução nutritiva com CE de 2,1 dS m-1 e em período de crescente disponibilidade de radiação solar (primavera-verão), os frutos representaram os maiores drenos de fotoassimilados. Segundo os modelos matemáticos, a condutividade elétrica da solução nutritiva que maximizaria a produção de matéria seca e a produtividade é de aproximadamente 3,0 dS m-1, em ambos os ciclos de cultivo.

With the objective of evaluating the effect of different ionic concentrations of the nutrient solution on growth of summer squash cultivated in raw rice husk substrate with leaching recirculation, two experiments were conducted in two crop-seasons: spring-summer of 2005 and summer-autumn of 2006, in Pelotas, RS. Four ionic concentrations of the nutrient solution (based on electrical conductivity - EC) were studied: 1.3; 1.7; 2.1 and 4.2 dS m-1. Crop growth was determinated by the accumulated dry mass production and partitioning among the different above-ground plant organs (leafs, stem and fruits) at the end of the crop-seasons. Fruit yield was also evaluated. The obtained results indicate that ionic concentrations equal or lower than 1.7 dS m-1 were limiting for proper growth and yield of the crop. The effect of high ionic concentration of the nutrient solution (above 2.1 dS m-1) on dry mass production and partitioning varied according to the crop-season. The lower solar radiation availability of the summer-autumn crop season minimized the effects of the different concentrations of nutrient solution on dry mass production and partitioning to the fruits, as well as on the yield. The fruits comprised from 28 to 52% of the total above-ground dry mass production. Fruits represented the largest sink of assimilates of the plant only at 2.1 dS m-1 ionic concentration of the nutrient solution and in crescent solar radiation availability condition (spring-summer). According to the mathematics models, the electrical conductivity that maximizes dry mass production and yield is approximately 3.0 dS m-1 for both crop-seasons.

Produção de clamidósporos de Pochonia chlamydosporia em diferentes substratos / Production of chlamydospores of Pochonia chlamydosporia in different substrates

Clamidósporos são estruturas de sobrevivência do fungo nematófago Pochonia chlamydosporia. Objetivou-se, com este trabalho, avaliar diferentes substratos, teores de água e formas de inóculo para a produção in vitro de clamidósporos de P. chlamydosporia. Inicialmente, testaram-se os substratos grãos de milho triturado, grãos de arroz e casca de café e os tipos de inóculo meio líquido concentrado ou diluído (1:40) e discos de cultura, colonizados por P. chlamydosporia. Posteriormente, testou-se o substrato grãos de milho triturado suplementado ou não com caldo de batata com os inóculos do fungo nas formas de discos de micélio ou suspensão aquosa. As maiores produções de clamidósporos g-1 de substrato foram obtidas nos substratos grãos de milho triturado e casca de café, e as melhores formas de inóculo foram meio líquido diluído (1:40) e discos de micélio. A suplementação do substrato grãos de milho triturado com caldo de batata não aumentou a produção de clamidósporos do fungo e a melhor forma de inóculo do fungo foi a de discos de micélio. Além disso, testaram-se os substratos canjica, grãos de arroz, casca de café e fibra de coco, umedecidos com diferentes quantidades de água; o substrato casca de café umedecido por diferentes períodos; a casca de café enriquecida ou não com sacarose e farinha de arroz e o substrato grãos de arroz esterilizado no forno micro-ondas com diferentes quantidades de água. Apenas o substrato grãos de arroz, em todas as quantidades de água testadas, apresentou maior produção de clamidósporos. Não houve diferença na produção de clamidósporos no substrato casca de café umedecido por diferentes períodos e apenas quando a casca de café foi enriquecida com farinha de arroz, apresentou maior média de clamidósporos g-1 de substrato. Todos os tratamentos apresentaram grande produção de clamidósporos g-1 quando o substrato utilizado foi o de grãos de arroz tratados no forno de micro-ondas. O melhor meio de cultivo de P. chlamydosporia para a produção de clamidósporos foi o substrato contendo grãos de arroz.

Chlamydospores are survival structures of the nematophagous fungus Pochonia chlamydosporia. The objective of this study was to evaluate different substrates, different contents of water and kinds of inoculum for the production of Pochonia chlamydosporia chlamydospores. The substrates evaluated were: milled maize, rice grains and coffee husk; all of them were inoculated with disks of culture, concentrated liquid media or diluted liquid media (1:40) colonized by P. chlamydosporia. Besides, the substrates milled maize, supplemented or not with potato broth, and inoculated with fungus disks or aqueous suspension were evaluated. Milled maize and coffee husk were the best substrates for chlamydospores production. The best inoculum kinds were disks of culture and diluted liquid media (1:40) colonized by P. chlamydosporia. The supplementation of milled maize with potato broth did not improve the production of chlamydospores, and the best inoculum form was disks of fungus. Moreover, it was also studied the substrates rice grains, coffee husk and coconut fibers with different rates of water; the substrate coffee husk moistened by different periods; the supplementation of coffee husk with rice flour or dextrose; and the substrate grains of rice sterilized in microwave oven with different rates of water. The substrate grains of rice, in all of the amounts of water tested showed increase in production of chlamydospores. There was no difference in the chlamydospores production of the coffee husk substrate, when moistened by different periods of time and only when it was supplemented with rice flour it showed higher mean of clamydospores per gram of substrate. All treatments evaluated showed higher production of chlamydospores in the substrate grains of rice treated in the microwave oven. The best substrate for the production of chlamydospores of P. chlamydosporia was the rice grains.

Crescimento do morangueiro: influência da cultivar e da posição da planta no canteiro / Strawberry growth: effect of cultivar and plant position in the bed

O objetivo deste trabalho foi avaliar o crescimento de cultivares de morangueiro em sistema de cultivo orgânico, observando a influência da posição da planta no canteiro sobre a produção acumulada e a partição de massa seca entre os órgãos aéreos das plantas. O experimento foi realizado na Embrapa Clima Temperado, Estação Experimental Cascata, Pelotas, RS. Os tratamentos constaram da combinação de dois fatores experimentais: cultivar ('Albion', 'Aromas', 'Camarosa' e 'Camino Real') e a posição das plantas no canteiro (Central e Bordadura). O delineamento experimental adotado foi o de blocos completos casualizados com parcelas divididas e quatro repetições. A cultivar 'Camarosa' apresentou maior produção de massa seca dos órgãos aéreos das plantas (62,3; 27,5 e 88,0g planta-1 para folha, coroa e frutos, respectivamente) e, juntamente com a 'Aromas', maior produtividade (64,2 e 59,1Mg ha-1, respectivamente). A cultivar 'Aromas' apresentou a maior contribuição proporcional dos frutos para a composição do total de massa seca da planta (60,6 por cento) e o maior índice de colheita (88 por cento). A posição das plantas não influenciou o crescimento e a produtividade, indicando ausência de efeito de bordadura para as cultivares 'Albion', 'Aromas', 'Camarosa' e 'Camino Real'.

The aim of this research was to evaluate the growth of strawberry cultivars growing in organic crop system observing the influence of plant position in the bed on accumulated dry matter production and its partitioning among the aboveground plant organs. The experiment was conducted in Embrapa Clima Temperado, Estação Experimental Cascata, Pelotas, RS. The treatments were compose by the combination of two experimental factors: cultivar ('Aromas', 'Albion', 'Camarosa' and 'Camino Real') and plant position in the bed (Central and Border). The experimental design used was randomized blocks with split-plots and four replications. 'Camarosa' cultivar presented highest dry mass production of aboveground organs (62.3; 27.5 and 88.0g plant-1 for leaves, crown and fruits, respectively), and together 'Aromas', highest yield (64.2 and 59.1Mg ha-1, respectively). 'Aromas' cultivar presented highest fruit dry mass contribution for the total aboveground dry mass production (60.6 percent) and the highest harvest index (88 percent). The plant position in the bed did not influence the growth and yield of the plants, which indicate no border effect for the 'Albion', 'Aromas', 'Camarosa' and 'Camino Real' strawberry cultivars.

Crescimento do morangueiro: influência da cultivar e da posição da planta no canteiro

The aim of this research was to evaluate the growth of strawberry cultivars growing in organic crop system observing the influence of plant position in the bed on accumulated dry matter production and its partitioning among the aboveground plant organs. The experiment was conducted in Embrapa Clima Temperado, Estação Experimental Cascata, Pelotas, RS. The treatments were compose by the combination of two experimental factors: cultivar ('Aromas', 'Albion', 'Camarosa' and 'Camino Real') and plant position in the bed (Central and Border). The experimental design used was randomized blocks with split-plots and four replications. 'Camarosa' cultivar presented highest dry mass production of aboveground organs (62.3; 27.5 and 88.0g plant-1 for leaves, crown and fruits, respectively), and together 'Aromas', highest yield (64.2 and 59.1Mg ha-1, respectively). 'Aromas' cultivar presented highest fruit dry mass contribution for the total aboveground dry mass production (60.6%) and the highest harvest index (88%). The plant position in the bed did not influence the growth and yield of the plants, which indicate no border effect for the 'Albion', 'Aromas', 'Camarosa' and 'Camino Real' strawberry cultivars.

O objetivo deste trabalho foi avaliar o crescimento de cultivares de morangueiro em sistema de cultivo orgânico, observando a influência da posição da planta no canteiro sobre a produção acumulada e a partição de massa seca entre os órgãos aéreos das plantas. O experimento foi realizado na Embrapa Clima Temperado, Estação Experimental Cascata, Pelotas, RS. Os tratamentos constaram da combinação de dois fatores experimentais: cultivar ('Albion', 'Aromas', 'Camarosa' e 'Camino Real') e a posição das plantas no canteiro (Central e Bordadura). O delineamento experimental adotado foi o de blocos completos casualizados com parcelas divididas e quatro repetições. A cultivar 'Camarosa' apresentou maior produção de massa seca dos órgãos aéreos das plantas (62,3; 27,5 e 88,0g planta-1 para folha, coroa e frutos, respectivamente) e, juntamente com a 'Aromas', maior produtividade (64,2 e 59,1Mg ha-1, respectivamente). A cultivar 'Aromas' apresentou a maior contribuição proporcional dos frutos para a composição do total de massa seca da planta (60,6%) e o maior índice de colheita (88%). A posição das plantas não influenciou o crescimento e a produtividade, indicando ausência de efeito de bordadura para as cultivares 'Albion', 'Aromas', 'Camarosa' e 'Camino Real'.

Crescimento do morangueiro: influência da cultivar e da posição da planta no canteiro

The aim of this research was to evaluate the growth of strawberry cultivars growing in organic crop system observing the influence of plant position in the bed on accumulated dry matter production and its partitioning among the aboveground plant organs. The experiment was conducted in Embrapa Clima Temperado, Estação Experimental Cascata, Pelotas, RS. The treatments were compose by the combination of two experimental factors: cultivar ('Aromas', 'Albion', 'Camarosa' and 'Camino Real') and plant position in the bed (Central and Border). The experimental design used was randomized blocks with split-plots and four replications. 'Camarosa' cultivar presented highest dry mass production of aboveground organs (62.3; 27.5 and 88.0g plant-1 for leaves, crown and fruits, respectively), and together 'Aromas', highest yield (64.2 and 59.1Mg ha-1, respectively). 'Aromas' cultivar presented highest fruit dry mass contribution for the total aboveground dry mass production (60.6%) and the highest harvest index (88%). The plant position in the bed did not influence the growth and yield of the plants, which indicate no border effect for the 'Albion', 'Aromas', 'Camarosa' and 'Camino Real' strawberry cultivars.

O objetivo deste trabalho foi avaliar o crescimento de cultivares de morangueiro em sistema de cultivo orgânico, observando a influência da posição da planta no canteiro sobre a produção acumulada e a partição de massa seca entre os órgãos aéreos das plantas. O experimento foi realizado na Embrapa Clima Temperado, Estação Experimental Cascata, Pelotas, RS. Os tratamentos constaram da combinação de dois fatores experimentais: cultivar ('Albion', 'Aromas', 'Camarosa' e 'Camino Real') e a posição das plantas no canteiro (Central e Bordadura). O delineamento experimental adotado foi o de blocos completos casualizados com parcelas divididas e quatro repetições. A cultivar 'Camarosa' apresentou maior produção de massa seca dos órgãos aéreos das plantas (62,3; 27,5 e 88,0g planta-1 para folha, coroa e frutos, respectivamente) e, juntamente com a 'Aromas', maior produtividade (64,2 e 59,1Mg ha-1, respectivamente). A cultivar 'Aromas' apresentou a maior contribuição proporcional dos frutos para a composição do total de massa seca da planta (60,6%) e o maior índice de colheita (88%). A posição das plantas não influenciou o crescimento e a produtividade, indicando ausência de efeito de bordadura para as cultivares 'Albion', 'Aromas', 'Camarosa' e 'Camino Real'.

Growth and yield of summer squash: effect of the ionic concentration of nutrient solution / Crescimento e produtividade da abobrinha italiana: efeito da concentração iônica da solução nutritiva

With the objective of evaluating the effect of different ionic concentrations of the nutrient solution on growth of summer squash cultivated in raw rice husk substrate with leaching recirculation, two experiments were conducted in two crop-seasons: spring-summer of 2005 and summer-autumn of 2006, in Pelotas, RS. Four ionic concentrations of the nutrient solution (based on electrical conductivity - EC) were studied: 1.3; 1.7; 2.1 and 4.2 dS m-1. Crop growth was determinated by accumulated dry mass production and partitioning among the different above-ground plant organs (leafs, stem and fruits) at the end of the crop-seasons. Fruit yield was also evaluated. The obtained results indicate that ionic concentrations equal or lower than 1.7 dS m-1 were limiting for proper growth and yield of the crop. The effect of high ionic concentration of the nutrient solution (above 2.1 dS m-1) on dry mass production and partitioning varied according to the crop-season. The lower solar radiation availability of the summer-autumn crop season minimized the effects of the different concentrations of nutrient solution on dry mass production and partitioning to the fruits, as well as on the yield. The fruits comprised from 28 to 52% of the total above-ground dry mass production. Fruits represented the largest sink of assimilates of the plant only at 2.1 dS m-1 ionic concentration of the nutrient solu

Com o objetivo de avaliar o efeito de diferentes concentrações iônicas da solução nutritiva sobre o crescimento e a produtividade da abobrinha italiana cultivada em substrato de casca de arroz in natura com recirculação dos lixiviados, foram realizados dois experimentos em duas épocas de cultivo: primavera-verão de 2005 e verão-outono de 2006, em Pelotas, RS. Quatro concentrações iônicas da solução nutritiva (com base na condutividade elétrica - CE) foram estudadas: 1,3; 1,7; 2,1 e 4,2 dS m-1. Determinou-se o crescimento da cultura, por meio da quantificação da produção e da partição de massa seca acumulada ao final dos ciclos de cultivo pelos diferentes órgãos aéreos da planta (folha, caule e frutos), e a produtividade. Os resultados obtidos nos experimentos indicam que concentrações iônicas iguais ou inferiores a 1,7 dS m-1 são limitantes para o adequado crescimento e produtividade da cultura. O efeito da alta concentração iônica da solução nutritiva (acima de 2,1 dS m-1) sobre a produção e a partição de massa seca varia de acordo com ciclo de cultivo. A menor disponibilidade de radiação solar no período de verão-outono minimiza os efeitos das diferentes concentrações da solução nutritiva sobre a produção e a partição de massa seca para os frutos, bem como sobre a produtividade. Os frutos representaram de 28 a 52% da massa seca total da parte aérea das plantas. Apenas na solu