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1.
Neotrop Entomol ; 46(3): 324-335, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27844467

RESUMEN

In Brazil, the Neotropical brown stink bug, Euschistus heros (F.) (Hemiptera: Pentatomidae), commonly disperses from soybeans to cotton fields. The establishment of an economic treatment threshold for this pest on cotton crops is required. Infestation levels of adults of E. heros were evaluated on cotton plants at preflowering, early flowering, boll filling, and full maturity by assessing external and internal symptoms of injury on bolls, seed cotton/lint production, and fiber quality parameters. A completely randomized experiment was designed to infest cotton plants in a greenhouse with 0, 2, 4, 6, and 8 bugs/plant, except at the full-maturity stage in which only infestation with 8 bugs/plant and uninfested plants were evaluated. Results indicated that the preflowering, early-flowering, and full-maturity stages were not affected by E. heros. A linear regression model showed a significant increase in the number of internal punctures and warts in the boll-filling stage as the population of bugs increased. The average number of loci with mottled immature fibers was significantly higher at 4, 6, and 8 bugs compared with uninfested plants with data following a quadratic regression model. The seed and lint cotton was reduced by 18 and 25% at the maximum level of infestation (ca. 8 bugs/plant) in the boll-filling stage. The micronaire and yellowing indexes were, respectively, reduced and increased with the increase of the infestation levels. The economic injury level of E. heros on cotton plants at the boll-filling stage was determined as 0.5 adult/plant. Based on that, a treatment threshold of 0.1 adult/plant can be recommended to avoid economic losses.


Asunto(s)
Productos Agrícolas/economía , Glycine max , Gossypium , Heterópteros , Animales , Brasil , Control de Plagas , Semillas
2.
Neotrop Entomol ; 42(1): 82-8, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23949716

RESUMEN

The boll weevil Anthonomus grandis Boheman (Coleoptera: Curculionidae) is the most important cotton pest in Brazil. A large-scale field-testing of a Boll Weevil Suppression Program (BWSP) was implemented to assess its technical and operational feasibility for boll weevil suppression in the state of Goiás, Brazil. The pilot plan focused on 3,608 ha of cotton during the 2006/2007 and 6,011 ha in the 2007/2008 growing seasons; the areas were divided into four inner zones with an outer buffer zone. We analyzed data on boll weevil captures using pheromone traps installed in the BWSP fields, on the detection of the first insect and the first damaged floral bud, greatest damage, and number of insecticide applications. The nonparametric Mann-Whitney U test was used to evaluate the differences between presuppression and suppression years. Fourteen pheromone-baited trapping evaluations were used to compare the weevil populations from 2006/2007 and 2007/2008 growing seasons. The BWSP regime reduced in-season boll weevil captures from 15- to 500-fold compared to presuppression levels in the preceding year. The low capture rates were related to delays in infestation and damage by weevils. The smaller population size measured by trapping and field monitoring reduced the number of required insecticide treatments. The BWSP strategy was efficient in suppressing populations of this pest and is a viable program for cotton production in subtropical and tropical regions, with long-term economic and environmental benefits.


Asunto(s)
Control de Insectos , Gorgojos , Animales , Brasil , Evaluación de Programas y Proyectos de Salud
3.
Neotrop Entomol ; 42(4): 359-65, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23949855

RESUMEN

The neotropical brown stink bug, Euschistus heros (F.), is a phytophagous pentatomid that causes considerable economic losses in soybean crop, but it has been recently reported using cotton as a new host plant. Nymphs and adults of E. heros were raised on six different food sources composed of the reproductive structures of cotton and soybean plants: a standard diet (green-bean pods + raw peanuts + privet fruits), soybean seeds, soybean pods, cotton seeds, cotton bolls, and cotton floral buds. The following biological parameters were evaluated: nymph developmental time, instar duration, and survivorship; adult weight at emergence; male and female longevity; duration of pre-oviposition and oviposition periods; and female fecundity and fertility. Nymphal development time and survival, as well as the adult weight and fecundity of E. heros fed on cotton bolls and seeds were reduced if compared to those fed on soybean pods. The cotton floral buds did not support the immature development nor the reproduction of adults of E. heros. Most of the cotton plant structures fed to E. heros caused high nymph mortality and low adult fertility. Cotton, therefore, appeared to be an unsuitable host for the development and reproduction of E. heros. Therefore, our data may allow us to suggest that the occurrence of E. heros on cotton may be due to occasional dispersion in search for shelter.


Asunto(s)
Conducta Alimentaria , Glycine max/parasitología , Gossypium/parasitología , Heterópteros/fisiología , Animales , Femenino , Flores , Masculino , Ninfa , Reproducción , Semillas
4.
Arq. Inst. Biol. (Online) ; 78(4): 545-551, out.-dez. 2011. tab
Artículo en Portugués | VETINDEX | ID: biblio-1414612

RESUMEN

O bicudo Anthonomus grandis (Boheman 1843) (Coleoptera: Curculionidae) é considerado a principal praga do algodoeiro no Brasil e uma das principais táticas de controle é o uso de inseticidas químicos. O desenvolvimento de produtos com modos de ação diferentes dos produtos convencionais é essencial para o manejo da resistência da praga e opções de controle químico. Este trabalho teve como objetivo avaliar a eficácia de alguns inseticidas neonicotinoides no controle do inseto. Os seguintes tratamentos foram aplicados a campo em 4 pulverizações com intervalos de 5 dias (9,8% de botões atacados no início do estudo): 1) Imidacloprid 200 SC (525 mL); 2) Imidacloprid 200 SC (700 mL); 3) Imidacloprid 200 SC (1.050 mL); 4) Thiamethoxam 250 WG (300 g); 5) Acetamiprid 200 SP (300 g); 6) Clothianidin 600 SC (262,5 mL); 7) Thiacloprid 480 SC (300 mL); 8) Endosulfan 350 CE (2.000 mL); e 9) Testemunha não tratada. O delineamento experimental foi o de blocos ao acaso com nove tratamentos e quatro repetições. As médias dos botões florais atacados por tratamento foram submetidas à análise de variância e comparadas pelo teste de Tukey (? = 0,05), enquanto que para o cálculo da eficiência dos inseticidas foi utilizada a fórmula de Abbott. Clothianidin 600 SC (262,5 mL p.c./ha) foi o neonicotinoide que apresentou a maior eficiência de controle (73% de controle aos seis dias após a terceira aplicação do inseticida). O ciclodieno Endosulfan 350 CE (2.000 mL do p.c./ha), utilizado como produto padrão do produtor, não controlou satisfatoriamente a praga como frequentemente citado. Não houve diferenças estatisticamente significativas entre os tratamentos para os parâmetros de produtividade (peso de algodão em caroço e número de capulhos por planta).


The boll weevil Anthonomus grandis (Boheman 1843) (Coleoptera: Curculionidae) is the most important cotton pest in Brazil, and insecticides play an important role in controlling its adults, so the development of products with new modes of action is essential to achieve successful control alternatives and resistance management options. The objective of this study was to evaluate the efficacy of some neonicotinoid insecticides to control the pest. The experimental design consisted of completely randomized blocks, with nine treatments and four replications. The following treatments (dosage of the commercial product per hectare) were applied in the field (with 9.8% of damaged squares at the beginning of the study): 1) Imidacloprid 200 SC (525 mL); 2) Imidacloprid 200 SC (700 mL); 3) Imidacloprid 200 SC (1,050 mL); 4) Thiamethoxam 250 WG (300 g); 5) Acetamiprid 200 SP (300 g); 6) Clothianidin 600 SC (262,5 mL); 7) Thiacloprid 480 SC (300 mL); 8) Endosulfan 350 CE (2,000 mL); and 9) Untreated control. The efficacy of insecticides was calculated with the Abbott formula; the data of damaged squares in each treatment was submitted to variance analysis and its means compared by Tukey test (? = 0.05). The results showed that Clothianidin 600 SC (262.5 mL/ha) was the most efficient neonicotinoid and reached 73% of efficacy at 6 days after the third application. The cyclodiene Endosulfan 350 CE (2,000 mL/ha), which was the standard farmer treatment, did not control the boll weevil as frequently cited. There were no significant differences in cotton production (fiber plus seed and bolls per plant) among treatments.


Asunto(s)
Resistencia a Medicamentos , Gorgojos/efectos de los fármacos , Endosulfano , Neonicotinoides/administración & dosificación , Insecticidas/administración & dosificación
5.
Neotrop Entomol ; 40(2): 258-63, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21584409

RESUMEN

The goal of this research was to use the sequential probability ratio test to establish a sequential sampling plan for Aphis gossypii Glover and Frankliniella schultzei Trybom infesting cotton. Field work was conducted at the agricultural experimental station of the Universidade Federal da Grande Dourados during the 2003/2004 and 2004/2005 agricultural years. Aphid colonies and individual thrips in the sampling area were counted and their numbers were recorded. The spatial distribution pattern of A. gossypii and F. schultzei in the cotton culture was aggregated. Sequential sampling plans were developed for aphids and thrips with type I and type II errors set at 0.1, common Kc = 0.6081 (aphids) and = 0. 9449 (thrips), and safety and management levels of 20% (aphids) and 40% (thrips) of infested plants. The sampling plans resulted in two decision boundaries for each species, as follows: the upper boundary, indicating when management (population control) is recommended: S1 = 4.6546 + 0.2849n (aphids), and S1 = 3.6514 + 0.1435n (thrips); and the lower boundary, indicating when population control is not necessary: S0 = -4.6546 + 0.2849n (aphids) and S0 = - 3.6514 + 0.1435n (thrips). The highest probability of error when making a decision was 3% for aphids and 2% for thrips, respectively. The maximum number of samples required to reach a decision was 63 for aphids and 95 for thrips.


Asunto(s)
Gossypium/parasitología , Control de Insectos/métodos , Insectos , Agricultura/métodos , Animales , Áfidos , Muestreo
6.
Arq. Inst. Biol. (Online) ; 78(1): 123-127, jan-mar, 2011. tab, graf
Artículo en Portugués | LILACS, VETINDEX | ID: biblio-1396443

RESUMEN

O pulgão Aphis gossypii Glover, 1877 (Hemiptera: Aphididae) é uma praga da cultura do algodão e quando não controlado pode reduzir a produtividade e a qualidade da fibra. A descoberta de novos grupos químicos de inseticidas para o controle do inseto traz perspectivas novas de manejo, e dentre os aficidas recentemente descobertos destacam-se pymetrozine e flonicamid. Este trabalho teve como objetivo avaliar a eficiência destes dois inseticidas no controle de A. gossypii quando absorvidos pela folha, caule e raiz de algodoeiro. Utilizou o delineamento experimental fatorial (2 x 3) com 5 repetições, em blocos casualizados. Cada parcela foi constituída de um vaso com duas plantas, mantidos sob condições de casa-de-vegetação, no ano de 2005. Avaliou-se a densidade populacional do pulgão nas folhas durante dezesseis dias após a aplicação dos tratamentos. Os resultados permitem concluir: (1) flonicamid apresentou eficiência de controle quando absorvido pelo caule e pelas folhas; (2) pymetrozine apresentou eficiência de controle através da absorção foliar; (3) a rota de absorção radicular não propiciou controle satisfatório para ambos aficidas; e, (4) em aplicação foliar os dois inseticidas não diferiram entre si quanto ao controle do pulgão-do-algodoeiro.


Aphis gossypii Glover, 1877 (Hemiptera: Aphididae) is a cotton pest, and if not controlled can reduce yield and fiber quality. The discovery of new chemical groups of insecticides brings new perspectives to IPM; pymetrozine and flonicamid are examples of new launched pesticides. This study was carried out to evaluate the efficacy of these two insecticides to control A. gossypii when they were absorbed by cotton root, stem and leaves. The statistical design was a randomized factorial (2 x 3) with five replications in blocks. Each plot consisted of a pot with two plants, kept under greenhouse conditions, in 2005. We evaluated the population density of aphids on the leaves during sixteen days after treatment. The results show: (1) flonicamid has efficiency when absorbed by stem and leaves, (2) pymetrozine efficacy is through foliar uptake, (3) the root absorption do not provide satisfactory control for both insecticides, and, (4) both insecticides control the aphid-cotton when is applied on leaves.


Asunto(s)
Áfidos , Piridinas/administración & dosificación , Gossypium/parasitología , Insecticidas/administración & dosificación , Tallos de la Planta/química , Raíces de Plantas/química , Hojas de la Planta/química
7.
Arq. Inst. Biol. ; 78(4)2011.
Artículo en Portugués | VETINDEX | ID: vti-759901

RESUMEN

ABSTRACT The boll weevil Anthonomus grandis (Boheman 1843) (Coleoptera: Curculionidae) is the most important cotton pest in Brazil, and insecticides play an important role in controlling its adults, so the development of products with new modes of action is essential to achieve successful control alternatives and resistance management options. The objective of this study was to evaluate the efficacy of some neonicotinoid insecticides to control the pest. The experimental design consisted of completely randomized blocks, with nine treatments and four replications. The following treatments (dosage of the commercial product per hectare) were applied in the field (with 9.8% of damaged squares at the beginning of the study): 1) Imidacloprid 200 SC (525 mL); 2) Imidacloprid 200 SC (700 mL); 3) Imidacloprid 200 SC (1,050 mL); 4) Thiamethoxam 250 WG (300 g); 5) Acetamiprid 200 SP (300 g); 6) Clothianidin 600 SC (262,5 mL); 7) Thiacloprid 480 SC (300 mL); 8) Endosulfan 350 CE (2,000 mL); and 9) Untreated control. The efficacy of insecticides was calculated with the Abbott formula; the data of damaged squares in each treatment was submitted to variance analysis and its means compared by Tukey test (? = 0.05). The results showed that Clothianidin 600 SC (262.5 mL/ha) was the most efficient neonicotinoid and reached 73% of efficacy at 6 days after the third application. The cyclodiene Endosulfan 350 CE (2,000 mL/ha), which was the standard farmer treatment, did not control the boll weevil as frequently cited. There were no significant differences in cotton production (fiber plus seed and bolls per plant) among treatments.


RESUMO O bicudo Anthonomus grandis (Boheman 1843) (Coleoptera: Curculionidae) é considerado a principal praga do algodoeiro no Brasil e uma das principais táticas de controle é o uso de inseticidas químicos. O desenvolvimento de produtos com modos de ação diferentes dos produtos convencionais é essencial para o manejo da resistência da praga e opções de controle químico. Este trabalho teve como objetivo avaliar a eficácia de alguns inseticidas neonicotinoides no controle do inseto. Os seguintes tratamentos foram aplicados a campo em 4 pulverizações com intervalos de 5 dias (9,8% de botões atacados no início do estudo): 1) Imidacloprid 200 SC (525 mL); 2) Imidacloprid 200 SC (700 mL); 3) Imidacloprid 200 SC (1.050 mL); 4) Thiamethoxam 250 WG (300 g); 5) Acetamiprid 200 SP (300 g); 6) Clothianidin 600 SC (262,5 mL); 7) Thiacloprid 480 SC (300 mL); 8) Endosulfan 350 CE (2.000 mL); e 9) Testemunha não tratada. O delineamento experimental foi o de blocos ao acaso com nove tratamentos e quatro repetições. As médias dos botões florais atacados por tratamento foram submetidas à análise de variância e comparadas pelo teste de Tukey (? = 0,05), enquanto que para o cálculo da eficiência dos inseticidas foi utilizada a fórmula de Abbott. Clothianidin 600 SC (262,5 mL p.c./ha) foi o neonicotinoide que apresentou a maior eficiência de controle (73% de controle aos seis dias após a terceira aplicação do inseticida). O ciclodieno Endosulfan 350 CE (2.000 mL do p.c./ha), utilizado como produto padrão do produtor, não controlou satisfatoriamente a praga como frequentemente citado. Não houve diferenças estatisticamente significativas entre os tratamentos para os parâmetros de produtividade (peso de algodão em caroço e número de capulhos por planta).

8.
Arq. Inst. Biol. ; 78(1)2011.
Artículo en Portugués | VETINDEX | ID: vti-759501

RESUMEN

ABSTRACT Aphis gossypii Glover, 1877 (Hemiptera: Aphididae) is a cotton pest, and if not controlled can reduce yield and fiber quality. The discovery of new chemical groups of insecticides brings new perspectives to IPM; pymetrozine and flonicamid are examples of new launched pesticides. This study was carried out to evaluate the efficacy of these two insecticides to control A. gossypii when they were absorbed by cotton root, stem and leaves. The statistical design was a randomized factorial (2 x 3) with five replications in blocks. Each plot consisted of a pot with two plants, kept under greenhouse conditions, in 2005. We evaluated the population density of aphids on the leaves during sixteen days after treatment. The results show: (1) flonicamid has efficiency when absorbed by stem and leaves, (2) pymetrozine efficacy is through foliar uptake, (3) the root absorption do not provide satisfactory control for both insecticides, and, (4) both insecticides control the aphid-cotton when is applied on leaves.


RESUMO O pulgão Aphis gossypii Glover, 1877 (Hemiptera: Aphididae) é uma praga da cultura do algodão e quando não controlado pode reduzir a produtividade e a qualidade da fibra. A descoberta de novos grupos químicos de inseticidas para o controle do inseto traz perspectivas novas de manejo, e dentre os aficidas recentemente descobertos destacam-se pymetrozine e flonicamid. Este trabalho teve como objetivo avaliar a eficiência destes dois inseticidas no controle de A. gossypii quando absorvidos pela folha, caule e raiz de algodoeiro. Utilizou o delineamento experimental fatorial (2 x 3) com 5 repetições, em blocos casualizados. Cada parcela foi constituída de um vaso com duas plantas, mantidos sob condições de casa-de-vegetação, no ano de 2005. Avaliou-se a densidade populacional do pulgão nas folhas durante dezesseis dias após a aplicação dos tratamentos. Os resultados permitem concluir: (1) flonicamid apresentou eficiência de controle quando absorvido pelo caule e pelas folhas; (2) pymetrozine apresentou eficiência de controle através da absorção foliar; (3) a rota de absorção radicular não propiciou controle satisfatório para ambos aficidas; e, (4) em aplicação foliar os dois inseticidas não diferiram entre si quanto ao controle do pulgão-do-algodoeiro.

9.
Arq. Inst. Biol ; 76(3)2009.
Artículo en Portugués | LILACS-Express | VETINDEX | ID: biblio-1462064

RESUMEN

ABSTRACT The adoption of a diagrammatic scale that allows for the estimation of the severity of cotton diseases is essential for decision-making in regard to the proper moment to control them chemically. During the main crops of 2000 and 2001 field experiments were carried out, with five replications, using a random complete block design, to compare the reproducibility of estimations of severity of leaf spot caused by Stemphylium spp., Alternaria spp., Ramularia areola and Xanthomonas axopodis pv. malvacearumthrough scores given by 4 evaluators using different diagrammatic scales: one developed by the present authors, one by ANDRADE et al (1999), one by CIA et al (1999) and one by CIA & SALGADO (1997) on DeltaOpal cultivar. The evaluations were performed by 4 different appraisers at 66, 81, 100 and 114 days after emergence in the crop year 2000/2001 and at 71, 86, 106 and 124 days after emergence in the season 2001/2002 in 40 marked plants per plot. The diagrammatic scale allowed the evaluators to estimate the severities of leaf spot with different levels of symptoms, in the same plant, showing more uniformity in the results when the severity of the diseases was lower. The CIA; SALGADO (1997) scale demanded more competence from the evaluators for the right use of it for determination of spot severities of the Stemphylium/ Alternaria complex. Scale 1 (created by the authors) and the CIA et al. (1999) scale were more appropriate for the detection of initial symptoms of the ramularia leaf spot.


RESUMO A adoção de escalas diagramáticas que viabilizem estimar a severidade de doenças no algodoeiro é fundamental para a tomada de decisão do momento mais correto de se fazer o controle químico destas enfermidades na cultura. Nas safras 2000/2001 e 2001/2002 foram realizados experimentos a campo, com cinco repetições, em delineamento de blocos ao acaso, objetivando comparar a reprodutibilidade da estimativa das severidades das manchas foliares causadas por Stemphylium spp., Alternaria spp., Ramularia areola e por Xanthomonas axonopodis pv. malvacearumpor meio de escalas diagramáticas: uma desenvolvida pelos autores deste trabalho, a de ANDRADE et al. (1999), a de CIA et al. (1999) e a de CIA; SALGADO (1997) na cultivar Delta Opal. As avaliações foram realizadas por quatro diferentes avaliadores aos 66, 81, 100 e 114 dias após a emergência no ano agrícola 2000/2001 e aos 71, 86, 106 e 124 dias após a emergência na safra 2001/2002 em 40 plantas marcadas por parcela. As escalas propiciaram aos avaliadores estimarem as severidades das manchas foliares com graus diferentes de sintomas, em planta, apresentando resultados mais uniformes quando a severidade das doenças era baixa. A escala de CIA; SALGADO (1997) exigiu maior competência dos avaliadores para a sua utilização adequada na determinação da severidade das manchas do complexo Stemphylium/Alternaria. As escalas 1 (elaborada pelos autores deste trabalho) e de CIA et al. (1999) demonstraram-se mais adequadas para a detecção dos sintomas iniciais da mancha de ramulária.

10.
Arq. Inst. Biol ; 74(2)2007.
Artículo en Portugués | LILACS-Express | VETINDEX | ID: biblio-1461873

RESUMEN

ABSTRACT plants, this experiment was carried out using the randomised complete block design with 4 replications (plots with 3,000 m²). The treatments were: 1) Pirephos (fenitrotion + esfenvalerate) 800 + 40 CE (0.6 L ha-1); 2) Sumidan (esfenvalerate) 150 CE (0.2 L ha-1); 3) Decis (deltametrin) 25 CE (0.4 L ha-1); 4) Thiodan (endosulfan) 350 CE (2.0 L ha-1); 5) Folidol (parathion methyl)) 600 CE (1.0 L ha-1) and 6) Control. The insecticides were applied at 62, 73, 84 and 95 days after crop emergence. To evaluate the biological disequilibrium an evaluation was made at the 125 days after crop emergence, by counting the number of infested plants with levels attribution for the symptoms severity found (damage scale from 1 to 10, where 1 = absence of symptoms and 10 = whole plants defoliated). The highest populational disequilibrium of the spider mite was caused by Folidol 600 CE, with 46% of infested plants and 1.72 average severity level; the second insecticide that caused more disequilibrium with 21.75% of infested plants and 0.5 for severity level was Thiodan 350 CE. The control and the other treatments were similar statistically.


RESUMO Objetivando-se avaliar o impacto de inseticidas químicos sobre a população de Tetranychus urticae Koch,1836 em algodoeiro foi realizado este experimento com delineamento experimental de blocos ao acaso e quatro repetições (parcelas de 3.000 m2). Os tratamentos foram: 1) Pirephos (fenitrotion + esfenvalerate) 800 + 40 CE (0,6 l.ha-1); 2) Sumidan (esfenvalerate) 150 CE (0,2 l.ha-1); 3) Decis (deltametrina) 25 CE (0,4 l.ha-1); 4) Thiodan (endosulfan) 350 CE (2,0 l.ha-1); 5) Folidol (parationa-metílica) 600 CE (1,0 l.ha-1); 6) testemunha. Os inseticidas foram aplicados aos 62, 73, 84 e 95 dias após a emergência da cultura. Para avaliar o desequilíbrio biológico foi feita uma avaliação aos 125 dias após a emergência, contando-se o número de plantas infestadas pela praga com atribuição de notas para a severidade dos sintomas encontrados (escala de dano de 1 a 10, onde 1 = ausência de sintoma e 10 = plantas inteiramente desfolhadas). Folidol 600 CE provocou o maior desequilíbrio populacional do ácaro-rajado, com 46% de plantas infestadas e nota média para a severidade igual a 1,72; Thiodan 350 CE apresentou 21,75% de plantas infestadas e nota 0,5 para a severidade sendo o segundo inseticida que mais desequilibrou. Os demais tratamentos foram estatisticamente semelhantes entre si e a testemunha.

11.
Arq. Inst. Biol ; 73(1)2006.
Artículo en Portugués | LILACS-Express | VETINDEX | ID: biblio-1461769

RESUMEN

ABSTRACT With the objective of identifying and quantifying the natural enemies associated to cotton pests sampling was made of these arthropods during the 2001/2002 and 2002/2003 crop season in Dourados, MS, Brazil. Evaluation was made of 100 plants in 20,000 m2, in a total of 20 samplings from 7 to 140 days after the plants' emergence, making use of the cotton cultivars DeltaOpal and Fibermax 986, in 2001/2002 and 2002/2003, respectively. In 2002/2003 samplings of the beneficial arthropods on the ground in the experimental area were made, through visual evaluations in the spaces between lines of plants in 25 plots of 100 m2 and through the utilization of 25 pitfall traps installed in each plot. For species most abundant in the ground the standard analysis was made of their spatial distribution using the Morisita index. In the two crop seasons, the Coccinellidae family was the most abundant of the complex of predators, with population levels following the fluctuation of a cotton aphid Aphis gossypii Glover population (Hemíptera: Aphididae). The suborder Heteroptera (Hemiptera) presented the highest diversity, with insects from 5 families, during the crop season 2001/2002. The pitfall trap method was more efficient than visual evaluation. Amongst the soil predators, the most abundant was Calosoma granulatumwhose standard of spatial distribution was aggregated in the experimental area.


RESUMO Com o objetivo de identificar a flutuação populacional dos inimigos naturais associados às pragas da cultura do algodoeiro, foram feitos levantamentos populacionais destes artrópodos nas safras 2001/2002 e 2002/2003 em Dourados, MS. Avaliaram-se 100 plantas ao acaso em uma área de 20.000 m2, num total de 20 amostragens dos 7 aos 140 dias após a emergência, utilizando-se as variedades DeltaOpal e Fibermax 986 em 2001/2002 e 2002/2003, respectivamente. Também, em 2002/2003 foram feitos levantamentos dos artrópodes benéficos sobre o solo da cultura, através de avaliações visuais nas entrelinhas das 25 parcelas de 100 m2, e através da instalação de 25 armadilhas do tipo pitfall. Para a espécie mais abundante dos predadores no solo foi realizada a análise padrão de sua distribuição espacial utilizando-se o índice de Morisita. Nas duas safras, a família Coccinellidae foi a mais abundante do complexo de predadores, com níveis populacionais que seguiram a flutuação populacional do pulgão Aphis gossypii Glover (Hemíptera: Aphididae). A subordem Heteroptera (Hemiptera) apresentou a maior diversidade com insetos de 5 famílias, na safra 2001/2002. O método da armadilha pitfall foi mais eficiente que a avaliação visual. Dentre os predadores de solo, o mais abundante foi Calosoma granulatum cujo padrão de distribuição espacial foi agregado.

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