Resumen La diversidad, la permanencia y la actividad de los artrópodos terrestres se investigaron en las tierras bajas de la costa del Pacífico de Colombia con el objetivo de identificar posibles especies depredadoras para el barrenador de la raíz de la palma de aceite, Sagalassa valida. Se establecieron diez trampas de caída a lo largo de un transecto de 100 m en cuatro áreas: un bosque secundario, una plantación de palma de chontaduro de 20 años y dos plantaciones híbridas de palma aceitera de tres y siete años, respectivamente. Se realizaron 22 recolectas cubriendo un año entero. Todas las hormigas se identificaron a nivel de especie o morfoespecie, los otros artrópodos se identificaron hasta orden o, cuando fue posible, a nivel de familia. En total, se capturaron 50.603 artrópodos, los más abundantes fueron hormigas (37,0 %), seguidos de Collembola (35,4 %), Acari (10,6 %), Coleoptera (7,0 %) y Diptera; Hemiptera y Araneae en porcentajes casi iguales (2,5 %). Los ortópteros (92 % Gryllidae) estaban presentes en todas las recolectas, siempre en números bajos. El mayor número de hormigas se registró en los transectos de palma aceitera; Diptera, Hemiptera y Orthoptera fueron más numerosos en el bosque secundario; Acari, Araneae y Collembola en el transecto de palma aceitera. Ectatomma ruidum fue la especie de hormiga dominante (84,9 % de todos los especímenes) y estuvo ausente en solo 20 de las 880 capturas. El segundo género de hormigas más frecuente fue el de las legionarias con dos especies, Labidus praedator y L. coecus. Las precipitaciones, incluso las inundaciones de toda el área, y la temperatura no explicaron satisfactoriamente la variabilidad en las capturas de ningún grupo taxonómico. Se concluye que E. ruidum podría ser el depredador que proporcione control del barrenador de la raíz y se recomiendan estudios adicionales sobre su eficiencia.

Abstract Diversity, permanence, and activity of terrestrial arthropods were investigated in four areas of different land use in the lowlands of the Pacific coast of Colombia with the aim to identify potential predator species for the palm root borer, Sagalassa valida. Ten pitfall traps were established along a 100 m transect in four areas: a secondary forest, a 20 year.-old peach palm plantation, and two hybrid oil palm plantations of three and seven years of age, respectively. Twenty-two collections were made covering a whole year. All ants were identified to species or morphospecies level, the other arthropods to order or where possible to family level. In total, 50,603 arthropods were captured, the most abundant were ants (37.0 %), followed by Collembola (35.4 %), Acari (10.6 %), Coleoptera (7.0 %) and Diptera, Hemiptera and Araneae in almost equal numbers (around 2.5 %). Orthoptera (92 % Gryllidae) were present in all collections, always at low numbers. The highest number of ants were recorded in the oil palm transects; Diptera, Hemiptera and Orthoptera were more numerous in the secondary forest, Acari, Araneae and Collembola in the palm transects. Ectatomma ruidum was by far the dominant ant species (84.9 % of all specimens) and absent from only 20 of the 880 captures. The second most frequent ant genus were army ants with two species, Labidus praedator and L. coecus. Rainfall, even area-wide flooding, and temperature did not explain variability in captures of any taxonomic group satisfactorily. We conclude that E. ruidum might be the predator to provide control of the root borer and recommend further studies on its efficiency.

RESUMO: Neste estudo, objetivamos investigar a infestação de Cosmopolites sordidus ( Coleoptera: Dryophthoridae ) em diferentes genótipos de bananeira, em um pomar comercial de bananeira, com idade de 30 meses. Para isso, comparou-se a infestação da broca-da-rizoma em 20 genótipos de bananeira, sendo cinco variedades e quinze híbridos. No geral, foi observado que 94,17% da infestação da praga ocorreu na região do córtex do rizoma, e apenas 5,83% das plantas apresentaram infestação no cilindro central. Os materiais menos sensíveis à infestação foram as variedades Prata Anã (AAB) e Pacovan (AAB), nas quais não foi registrada ocorrência da praga. Entre os genótipos híbridos, de forma geral, os materiais PV 9401 e BRS FHIA 18 foram os que apresentaram sensibilidade intermediária, enquanto os híbridos BRS Tropical (AAAB), PA 9401 (AAAB), BRS Vitoria (AAAB), YB-4203 (AAAB) e Bucaneiro (AAAA) foram os mais sensíveis ao ataque da broca-do-rizoma. Este estudo demonstra que a infestação da broca-do-rizoma varia de acordo com o genótipo, e a seleção de materiais menos suscetíveis auxilia na redução da infestação de C. sordidus.

ABSTRACT: In this study, we aimed to investigate Cosmopolites sordidus (Coleoptera: Dryophthoridae ) infestation among different banana genotypes in a commercial banana orchard over the course of 30 months. Banana root borer infestation was compared in 20 banana genotypes, including five varieties and 15 hybrids. Overall, we observed that 94.17% of pest infestation cases occurred in the cortex region, and only 5.83% occurred in the central cylinder. Genotypes least sensitive to infestation were the Prata Anã (AAB) and Pacovan (AAB) varieties, where no damage was recorded. Among the hybrid genotypes, PV 9401 and BRS Fhia 18 showed intermediate levels of sensitivity, while BRS Tropical hybrids (AAAB), PA 9401 (AAAB), BRS Vitoria (AAAB), YB 4203 (AAAB), and Bucaneiro (AAAA) were the most sensitive to attack by banana root borer. This study demonstrated that the infestation of the banana root borer varies according banana plant genotype, and the utilization of less susceptible genotypes could reduce infestation rates of C. sordidus.

L. Parra, A. Mutis, F. Ortega, and A. Quiroz. 2013. Field response of Hylastinus obscurus Marsham (Coleoptera: Curculionidae) to ,E-2-hexenal and limonene, two host-derived semiochemicals. Cien. Inv. Agr. 40(3): 637-642. Red clover (Trifolium pratense L.), a valuable legume in Chile, is important mainly for seed production and as forage for animal production. Although it is considered a perennial, the productivity of this legume declines during the second year of growth primarily because of infestation by the red clover root borer, Hylastinus obscurus (Coleoptera: Curculionidae). Currently, there is no efficient method for controlling this insect, although the use of semiochemicals may provide a new alternative to reduce the damage caused by this curculionid. In this context, E-2-hexenal and limonene, which were previously determined to be an attractant and a repellent, respectively, for H. obscurus, were released from dispensers established in two cultivars (Quiñequeli INIA and Superqueli INIA) and one experimental line (Syn II Pre III) of red clover at the Centro Regional de Investigación Carillanca (INIA-Carillanca) (Vilcún, Chile). H. obscurus was found in significantly higher numbers on plants from areas treated with E-2-hexenal than from areas treated with limonene or in areas that were left untreated as control areas. However, this attractiveness was influenced by the red clover source such that the effect of E-2-hexenal was observed in Superqueli INIA and Syn II Pre III but not in Quiñequeli INIA. Unlike previous studies, limonene had no effect on H. obscurus. Our results provide the first evidence under field conditions for the potential use of E-2-hexenal as an attractant for the red clover root borer H. obscurus.

L. Parra, A. Mutis, F. Ortega y A. Quiroz. 2013. Respuesta de Hylastinus obscurus Marsham (Coleoptera: Curculionidae) a ,E-2-hexenal y limoneno, dos semioquímicos derivados de su hospedero, en condiciones de campo. Cien. Inv. Agr. 40(3): 637-642. El trébol rosado es una valiosa leguminosa, cuya importancia en Chile radica principalmente en la producción de semillas y su uso como alimento forrajero. A pesar de ser una planta perenne, su producción declina durante el segundo año de establecida, debido principalmente a la infestación del barrenador de la raíz del trébol Hylastinus obscurus (Coleoptera: Curculionidae). Actualmente no existe un método de control eficiente contra este insecto, por lo tanto, el uso de semioquímicos surge como una nueva alternativa para disminuir los daños ocasionados por este curculiónido. En este contexto, E-2-hexenal y limoneno, determinados previamente como atrayente y repelente a H. obscurus, fueron dispuestos en dispensadores de liberación lenta establecidas en dos cultivares y una línea experimental de trébol rosado en Centro de Investigación INIA Carillanca (Vilcún, Chile). Las evaluaciones indican que H. obscurus fue significativamente encontrado en mayor proporción en plantas sometidas al tratamiento con E-2-hexenal, comparadas con limoneno y el control. Sin embargo, este efecto atrayente fue influenciado por los cultivares y línea experimental de trébol rosado, de tal manera que el efecto de E-2-hexenal fue observado en Superqueli INIA y Syn II Pre III, pero no en Quiñequeli INIA. En contraste a previos estudios, limoneno no tuvo efecto sobre H. obscurus. Nuestros resultados permiten establecer la primera evidencia bajo condiciones de campo del potencial uso, especialmente E-2-hexenal, como un atrayente para H. obscurus.

Root volatiles from field-collected red clover plants, Trifolium pratense L., of five different ages were trapped by solid-phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). Ethanol, E-2-hexenal, hexanal, 3-octanone, limonene and a-pinene were identified. The electroantennographic (EAG) and olfactometric responses of clover root borer, Hylastinus obscurus, to the identified compounds were studied. The GC-MS with SPME as a solvent-free collection method identified ethanol and hexanal compounds that have not previously been reported in T. pratense. The EAG experiments showed that all of the tested compounds were perceived by H. obscurus, but mixed responses were found in behavioral assays. For females, ethanol and E-2-hexenal were attractive at one or more of the tested doses, while hexanal, 3-octanone, R-limonene and S-limonene were repellent at one or more of the tested doses. Females responded to a larger number of tested compounds and a wider range doses compared to males. This behavior could reflect a more active role of females in host finding and colonization.

O objetivo do trabalho foi avaliar o efeito de quatro tratamentos de sementes: água (T1), carbendazim + thiram (T2), fipronil + tiofanato metílico + piraclostrobina (T3) e abamectina + thiamethoxam + fludioxonil + mefenoxan + thiabendazole (T4) sobre parâmetros de crescimento de plantas de soja submetidas a dois regimes hídricos (presença e ausência de estresse hídrico) estabelecidos logo após a emergência das plântulas. O experimento foi conduzido em casa de vegetação e campo. Na casa de vegetação, nos tratamentos sem estresse hídrico, foram feitas quatro irrigações por dia e, nos tratamentos com estresse hídrico, foi realizada uma irrigação a cada três dias. Neste ensaio, foi avaliada a estatura de plantas, comprimento radicular, volume radicular, massa seca da parte aérea, massa seca radicular e área foliar. No ensaio de campo, o estresse hídrico foi estabelecido pela construção de túneis baixos de polietileno que impediram o fornecimento de água pela irrigação e chuva. No campo, foram avaliados estatura de planta, teor relativo de clorofila, emergência, ataque de lagarta-elasmo e rendimento de grãos. Nos dois ambientes, as plantas foram mantidas sob estresse até 28 dias após a emergência. Em casa de vegetação, todos os parâmetros foram influenciados pelo tratamento de sementes na presença e ausência de estresse hídrico. No campo, o tratamento com fipronil + tiofanato metílico + piraclostrobina (T3) e abamectina + thiamethoxam + fludioxonil + mefenoxan + thiabendazole (T4) proporcionaram maior estatura de planta e teor relativo de clorofila em ambos os regimes hídricos e maior emergência e rendimento de grãos em plantas sem e com restrição hídrica, respectivamente. Conclui-se que o tratamento de sementes com esses produtos promove alterações benéficas nas plantas, aumentando sua tolerância ao estresse hídrico, com efeito positivo sobre o rendimento de grãos da soja.

The objective of this research was evaluate four seed treatments: water (T1), carbendazim + thiram (T2), fipronil + thiophanate methyl + pyraclostrobin (T3) and abamectin + thiamethoxam + fludioxonil + mefenoxan + thiabendazole (T4) on growth parameters of soybean plants with or without low water availability. The experiments were conducted under field conditions and greenhouse. In greenhouse, in treatments without low water availability, it was made four irrigations by day and in treatments with low water availability, it was made one irrigation each three days. In this trial, it was evaluated the plant height, root length, root volume, dry shoot weight, dry root weight and foliar area. In the field trial, low water availability was established by construction of low tunnels of polyethylene which prevented the water supply by irrigation and rain. In the field, it was also evaluated the plant height, the relative chlorophyll content, emergence, lesser cornstalk borer attack and grain yield. In the both environment, the plants were kept on stress until 28th days after emergence. In greenhouse, all the parameters were influenced by seed treatments with or without low water availability. In field, the treatment with fipronil + thiophanate methyl + pyraclostrobin (T3) and abamectin + thiamethoxam + fludioxonil + mefenoxan + thiabendazole (T4) promoted higher plant height and relative chlorophyll content in both hydric schemes, higher emergence and grain yield in plants without and with lower water availability, respectively. It was concluded that seed treatment with these products promote benefit changes in plant, increasing its tolerance to hydric stress, with positive effect on soybean grain yield.

Objetivou-se determinar, em condições de campo, a dose mínima de fosfina para o controle da broca da raiz do cajueiro. Foram instalados 3 experimentos em épocas distintas, sendo o primeiro em agosto, o segundo em outubro e o terceiro em novembro de 1994 para o controle de Marshallius bondari Rosado-Neto (Coleoptera: Curculionidae) em cajueiro, Anacardium occidentale L. no município de Pio IX, Estado do Piauí. Foram testadas 1; 2; 3 e 6 pastilhas de fosfina na forma de fosfeto de alumínio, de 3 gramas cada, por planta. No ensaio conduzido em agosto nenhum tratamento foi eficiente para o controle de brocas adultas no solo. No ensaio instalado em outubro, a fosfina foi eficiente a partir de duas pastilhas por planta e no ensaio de novembro a partir de uma pastilha por planta para o controle de adultos no solo. A eficiência foi tanto maior quanto maior foi o tempo decorrido após a última chuva, estando, portanto, o solo mais seco.

The objective of this research was to determine, in field conditions, the minimal of phosphine effective dose for the cashew root borer control. Three experiments were set up at three different periods: August, October and November, 1994, to control the cashew root borer, Marshallius bondari Rosado-Neto (Coleoptera: Curculionidae), in Piaui State, Brazil. One, two, three and six phosphine tablets of three gram each, per plant were tested. In the August essay, phosphine was inefficient to control the borer. In the October essay, control was achieved using as little as 2 tablets per plant and in November with one tablet per plant to control the adult borers in the soil. Higher efficiency was achieved when treatment was applied far away from the last rain, in other words, as soil dries out.

Red clover (Trifolium pratense L.) is a valuable forage legume grown alone or in mixture with grasses in temperate regions of the world. Red clover is adapted to a wide range of soil types, pH levels, environmental and management conditions. However, the main limitation of this species is the lack of persistence related to the high mortality of plants. In Chile the main biotic factor affecting survival of plants is the root borer Hylastinus obscurus (Marsham) (Coleóptera; Scolytidae). In 1989, a red clover (T. pratense L.) breeding program was started at Carillanca Research Center of the Institute of Agricultural Research (INIA), Chile, with the main objectives of improving the survival of plants, forage yield and persistence. In 2002 a research line to study the interaction between the root borer and the plant was started. This paper describes briefly the improvement obtained in survival of young plants after twenty years of breeding and the importance of root borer population regarding forage yield. Experiments were conducted at Carillanca Research Center under irrigated conditions, comparing under cutting the dry matter yield of new synthetic lines and Redqueli-INIA with Quinequeli-INIA. The experimental lines Syn Int IV, Syn Pre III, Syn Int V and Syn Int VI were more productive than the cultivars Redqueli-INIA and Quiñequeli-INIA at the second season. The evaluation of the biological parameter allowed identifying a tolerant line, Syn Pre I, and three potential new varieties: Syn Pre III, Syn Int V and Syn Int VI. This is the first report showing an inverse relation between dry matter yield of red clover and root borer population (P<0.05). Moreover, we report the first evidence that H. obscurus start the colonization of red clover plant of 6-month-old.

Se evaluaron la movilidad y velocidad de los nemátodos entomopatógenos (Steinernema sp. SNIO198) en suelos de una plantación de palma de aceite en Tumaco, Colombia con el fin de establecer si este sistema de control podría ser aplicado para manejar Sagalassa valida una de las principales plagas que afecta las plantaciones. Se utilizaron columnas plásticas de 25 cm de alto con dos texturas de suelo y cuatro niveles de humedad. 500 nemátodos fueron ubicados en la parte superior, y en la parte inferior de la columna (24 cm) se ubicaron larvas de S. valida dentro de raíces primarias de palma y también completamente expuestas. El número de juveniles infectivos (JI) de Steinernema sp., se evaluó a tres profundidades a las 24, 48, 72 y 96 horas después de aplicados los nemátodos. Los resultados muestran que si las larvas de S. valida están totalmente expuestas la mayoría de JI se recuperaron entre 48 y 72 horas. Sí las larvas están dentro de raíces de palma, la mayoría de los JI se recolectaron entre las 24 y 48 horas. Además, el desplazamiento de los JI en las dos texturas de suelo fue gradual. Los primeros JI que lograron alcanzar el hospedero penetraron; otros se localizaron en la proximidad de las larvas o especialmente en las raíces o en las tres secciones de profundidad evaluadas. La principal conclusión, es que Steinernema sp. SNIO198 tiene comportamiento crucero y emboscador.

The mobility and speed of entomopathogenic nematodes (Steinernema sp. SNIO198) were evaluated in soils of an oil palm plantation in Tumaco, Colombia in order to establish whether this control system could be applied for the management of Sagalassa valida, one of the most important pests that affects plantations. Plastic columns, 25 cm long, were used with two soil textures and four humidity levels. Five hundred nematodes were placed on top of each soil column, and in the lower part (24 cm) S. valida larvae were placed both inside primary palm roots and completely exposed. The number of Steinernema sp. infective juveniles (IJ) was evaluated at three depths at 24, 48, 72 and 96 hours after nematode application. The results showed that if the S. valida larvae are completely exposed, the majority of IJ were recovered between 48 and 72 hours. If the larvae are located inside palm roots, the majority of IJ were collected after 24 and 48 hours. Also, the movement of IJ in the two soil textures was gradual. The first IJ that could reach the host penetrated it; others stayed near the larvae or especially in the roots or in any of the three depths evaluated. The main conclusion is that Steinernema sp. SNIO198 exhibits cruising and ambush behavior.

Resumen: Sagalassa valida, el barrenador de las raíces de palma de aceite (Elaeis guineensis), es una de las plagas más importantes en el Occidente de Colombia, (Tumaco, Nariño). Sin embargo, no se tiene conocimiento sobre la biología de los estados larvales. Por ende, para poder manejar este insecto, se estableció el estudio de velocidad de desplazamiento de larvas de primer instar en palmas de vivero. Para ello se utilizaron cilindros de PVC con cuatro perforaciones de diferentes diámetros 0, 5, 10 y 15 cm, las cuales se infestaron con huevos de S. valida. Cada 24 horas hasta las 96 horas se determinó el comportamiento y desplazamiento a estas profundidades en donde se encontraban las raíces de palma. Al final del ensayo, se estableció que las larvas no superan los 3 cm de profundidad, encontrando el mayor porcentaje en las raíces ubicadas prácticamente a ras del suelo. Las larvas consumen las raíces cuaternarias y terciarias desde su ápice, realizan movimientos circulares y longitudinales. El tiempo y profundidad evidenciaron efectos significativos en la abundancia de larvas en suelo y en las raíces de la palma.

Abstract : Sagalassa valida, the oil palm rootworm (Elaeis guineensis), is one of the most important pests from Western Colombia, Tumaco (Nariño). However, there is no knowledge about the biology of the larval stages. Therefore to manage this insect, a study was established on the speed of movement of the first instar larvae in greenhouse palms. To do this, Polyvinyl chloride (PVC) tubes were used with four holes of different diameters 0, 5, 10 and 15 cm, which were infested with S. valida eggs. Every 24 hours up to 96 hours the behavior and movement was determined according to the depth at which roots were found. At the end of the assay, it was concluded that larvae did not exceed a depth of 3 cm, finding the greatest percentage in the roots located practically on the surface of the soil. The larvae consume quaternary and tertiary roots starting from their apex, making circular and longitudinal movements. The time and depths showed significant effects on the abundance of larvae in the soil and palm roots.

The incidence of Tuta absoluta in tomato production, the use of pesticides for its control, the risk of contamination to the environment and the creation of a generation of resistance, makes it very important to find alternative ways to efficiently control the tomato borer. This test was developed under greenhouse conditions to assess the effectiveness of the imidacloprid to the control of this pest at different rates and application forms. Two dilutions of the insecticide were prepared and applied in two different ways: by watering and by the immersion of the root of the plants into the soil bed. To evaluate the damage, calculations were carried out on the percentage of the leaves damaged on each plant and on the number of lesions on each leaf at different moments of the application. The design was factorial, completely randomized and with 9 replications, and an ANOVA was carried out. Significant differences were confirmed among the dilutions and also among the two application forms (watering and immersion). The better treatments were: dilution of 3,5% applied by watering and dilution of 7% applied by immersion.

La grave incidencia de Tuta absoluta en la producción de tomate, el alto uso de plaguicidas para su control, el riesgo de contaminación del ambiente y la generación de resistencia hacen que sea muy importante encontrar formas alternativas de control eficiente de esta plaga. Con el fin de evaluar la eficacia del imidacloprid en el control de la polilla del tomate, en distintas dosis y formas de aplicación se desarrolló este ensayo en condiciones de invernáculo. Para ello se prepararon dos diluciones del insecticida, que fueron aplicadas de dos formas: por riego y por inmersión de la raíz del plantín con su pan de tierra. Para evaluar el daño se realizó el cálculo del porcentaje de folíolos dañados por planta y el número de lesiones por hoja en distintos momentos desde la aplicación. El diseño fue factorial, completamente aleatorizado y con nueve repeticiones, aplicándose ANOVA. Se comprobó que hay diferencias significativas entre las diluciones y también entre las dos formas de aplicación (riego e inmersión). Siendo los tratamientos que mejor controlaron a la plaga: dilución al 3,5% aplicada por riego y dilución al 7% aplicada por inmersión.

Euplatypus segnis (Chapuis) (Coleoptera: Platypodidae) causes severe damage to pecan (Carya illinoensis) trees at Coahuila, Mexico. The present study was carried out during 1999-2001 in a 90 ha pecan orchard, divided in eight lots, during 1999-2001. The trees were counted and clasified in four categories: attacked by borer insects and with symptoms of cotton root rot (Phymatotrichopsis omnivora); only attacked by borer insects: only with symptoms of P. omnivora; and without pest neither disease. The attack by borer insects was significantly more frequent in pecans showing symptoms of P. omnivora than in those without symptoms. The dispersion of the pest adjusted to a Logistic model, with r² values of 0.871, 0.788 and 0.803 in 1999-2001, respectively. The absolute rate of dispersion of the borers was estimated at 2000-1999, 2001-2000 for each lot and year. The highest dispersion rates were observed in coinsidence with a soil moisture deficit in the orchard. The results indicate that frecuency of attack of the borers increases in tress with P. omnivora and irrigation deficit.

Euplatypus segnis (Chapuis) (Coleoptera: Platypodidae) causa daño severo a las plantaciones de nogal pecanero (Carya illinoensis) en Coahuila, México. Este estudio se llevó a cabo en una huerta de nogal de 90 ha dividida en ocho lotes, durante 1999-2001. Se contaron y clasificaron todos los árboles en cuatro categorías: 1) los atacados por insectos barrenadores y con síntomas de pudrición texana (Phymatotrichopsis omnivora), 2) los atacados por barrenadores, 3) los que presentaron síntomas visibles de la enfermedad y 4) los que no mostraron ataque de barrenadores ni síntomas de la enfermedad. La frecuencia de ataque de los barrenadores fue significativamente más alta en los árboles con síntomas de pudrición texana. La dispersión de la plaga se ajustó al modelo logistíco, con valores de 0.871, 0.788 y 0.803 de r² en 1999-2001, respectivamente. Se utilizó la velocidad instantánea de dispersión por lote y año, para obtener la tasa de dispersión 2000-1999 y 2001-2000. La mayor tasa de dispersión observada coincidió con el déficit de humedad en la huerta, aunque la prueba de t para los valores de las dos series de tasas se obtuvo un valor de p= 0.0623. Los resultados indican que la frecuencia de ataque de los barrenadores de nogal se incrementa significativamente en árboles con síntomas de P. omnivora y déficit de humedad en el suelo.

Com o uso de variedades adaptadas e o manejo do solo pós-colheita da soqueira de cana-de-açúcar em sistema de colheita mecanizada, poderá ser afetada a incidência de pragas e a produtividade do canavial. Assim, desenvolveu-se o presente trabalho com o objetivo de se avaliar a influência da palhada de dezoito variedades de cana-de-açúcar submetidas a diferentes sistemas de manejo de colheita mecânica, sem queima, na produtividade agrícola e na incidência de broca-comum e cigarrinha-das-raízes na cultura de cana-de-açúcar. Os tratamentos foram constituídos pela presença da palha sem trituração/sem cultivo (PST/SC); palha sem trituração/com cultivo com escarificador (PST/CC); palha triturada/com cultivo com escarificador (PT/CC). O rendimento de colmos na cana-soca é favorecido pelo manejo, com cultivo, da palhada da planta crua, colhida mecanicamente, sem alteração na incidência de broca-comum e da cigarrinha das raízes. A variedade SP87-365 de cana-de-açúcar é opção viável e rentável, em qualquer sistema de manejo da cana crua, com adaptação à colheita mecânica e às condições edafoclimáticas da região de Ribeirão Preto, SP. A incidência de broca-comum e da cigarrinha das raízes pode ser bastante reduzida com a utilização das variedades SP88-817 e SP76-112 de cana-de-açúcar, em qualquer sistema de manejo da palhada da cana crua colhida mecanicamente e minimizada na colheita mecânica da cana crua, seguida de trituração da palhada e cultivo com escarificador na entrelinha.

The use of adapted varieties of sugarcane and the soil management after its harvest in mechanized systems may affect the incidence of pests and the productivity of the sugarcane plantation. The objective of this work was to evaluate the influence of plant residues of 18 sugarcane varieties submitted to different harvest management systems on the agricultural productivity and incidence of moth borer and root froghopper. The treatments were: straw without triturating and cultivation (PST/SC); straw without triturating/with disk harrow cultivation (PST/CC); triturated straw/with disk harrow cultivation (PT/CC). The yield of stalk in the sugarcane is favored by the management, with cultivation, of the straw of the green plant, mechanically harvested, without alteration in the incidence of moth borer and root froghopper. The variety SP87-365 of sugarcane is a viable and rentable option in any system of management green sugarcane, with adaptation to the mechanical harvest and the edaphoclimatic conditions of the region of Ribeirão Preto, São Paulo State, Brazil. The incidence of moth borer and root froghopper can sufficiently be reduced with the adoption of the varieties SP88-817 and SP76-112 of sugarcane in any system of straw management of the green sugarcane mechanically harveste, and is minimized by the mechanical harvest of the green sugarcane followed by straw triturating and the use of disk harrow in the inter-row.

Com base nos resultados de seleção, obtidos pela equipe de melhoramento do algodoeiro do Instituto Agronômico (IAC), numa gleba naturalmente infestada pela broca-da-raiz, Eutinobothrus brasiliensis (Hambleton), da Estação Experimental de Tietê, em 1966-81, três índices de avaliação foram propostos para a resistência dessa planta à praga. O coeficiente de correlação simples entre as duas repetições dos testes anuais de progênies foi adotado como parâmetro para estudar a eficiência dos índices na seleção de progênies resistentes. Pelo estudo comparativo, escolheu-se, como o mais adequado, o índice obtido pela contagem de furos (galerias) observados na parte lenhosa, em corte oblíquo dos caules das plantas, feito na região do colo, no meio da parte hipertrofiada. Apresentam-se os coeficientes de correlação de 1972-81 e a discussão sobre a eficiência do índice escolhido que proporcionou, durante o período, um aumento gradual do coeficiente de correlação, significando um provável acúmulo de genes favoráveis à resistência nas progênies selecionadas. A prática de picar e enterrar a parte infestada dos caules, após a colheita dos dados, contribuiu para manter alta infestação da área pela broca. Aplicado, posteriormente, à avaliação de linhagens do programa de melhoramento do algodoeiro, o índice permitiu melhorar 50% o nível geral de resistência das linhagens em estudo.

To evaluate cotton resistance to the Brazilian root borer, Eutinobothrus brasiliensis (Hambleton), three indexes were proposed, based on selection data obtained in progeny tests, on a naturally infested plot, situated at the Tietê Experiment Station, in the years of 1966 to 1981, by the cotton breeders of the Instituto Agronômico, State of São Paulo, Brazil. The simple correlation coefficient between the two repetitions of the yearly tests was used as a parameter to study the efficiency of the indexes in selecting resistant progenies throughout that period. The most adequate index for evaluating progenies was the one obtained by the number of holes ("galleries"). The "galleries index" was observed in the woody part through an oblique section in the middle of the gall, located near the basis of the main stem of the plant. The correlation coefficients obtained in the years of 1972 to 1981 are presented and the index efficiency is discussed. The use of this index resulted in a gradual increase of the correlation coefficient, probably due to a cumulative selection of favourable resistance genes in the progenies. A high level of infestation could be maintained by picking and incorporating to the soil, the infested parts of the stems, just after data had been taken. In subsequent years, the use of the index resulted in a 50% increase in the average resistance of the selected lines of the Cotton Breeding Program.