Cereals constitute a relevant part of human and domestic animal diet. Under storage conditions, one of the most significant problems of these crops is insect pests as the maize weevil (Sitophilus zeamais Motschulsky). This insect species is usually controlled by means of synthetic insecticides but problems as toxic residues and resistance has led to the search for more friendly control alternatives such as botanical insecticides. The aim of this research was to evaluate, under laboratory conditions, the insecticidal properties of the powder and the essential oil of peumo (Cryptocarya alba [Molina] Looser; Lauraceae) leaves against S. zeamais. The variables assessed were toxicity by contact and fumigant activity, adult emergence (F1), repellent effect, and impact on wheat (Triticum aestivum L.) seed germination. A completely randomized design was used with five treatments and 10 replicates. The higher mortality levels were obtained at 80 g powder kg-1 grain and 40 mL essential oil kg-1 grain of C. alba; in both cases, the mortality of adult S. zeamais surpassed 80%. The emergence of adults S. zeamais (F1) was reduced by 100% at 80 g powder kg-1 grain and 40 mL essential oil kg-1 grain. Germination of wheat seeds treated with C. alba powder and essential oil was not affected. Both, the powder and the oil treatments showed repellent effect, but not fumigant activity.

The maize weevil Sitophilus zeamais Motschulsky is a worldwide key pest of stored products. Usually contact insecticides or fumigants are used against it, but problems as toxic residues, human intoxications, and resistance have triggered the search for alternative control methods as the use of essential oils. The objective of this research was to assess under laboratory conditions, the insecticidal properties of Laurelia sempervirens (Ruiz & Pav.) Tul. essential oil against S. zeamais. In contact toxicity bioassay assessed treatments were 0 (control), 1.25, 2.5, 5.0, 10, 20, and 40 mL essential oil kg-1 grain and 0 (control), 25, 50, 75, 100, 125, 150, and 175 μL essential oil L-1 air in fumigant toxicity tests. The highest toxicity by contact activity was reached by concentrations higher than 10 mL essential oil kg-1 grain (100% mortality). The same treatments totally inhibit F1. The dose of 175 μL essential oil L-1 air showed a significant toxicity by fumigant activity causing 72.5% of dead insects. The other treatments did not surpass 5% mortality. In offspring effect (F1) bioassay, all treatments had an insect emergence significantly lower than the control but concentrations equal or higher than 10 mL essential oil kg-1 grain prevented the emergence of F1 during the 7 wk of bioassay. The residual effect of contact toxicity remained by 15 d. The treatments based on essential oil lead to a weight grain loss lower than control and germination was not affected. All assessed treatments showed repellent effect. The essential oil of L. sempervirens has promissory perspectives to maize weevil control.

The maize weevil (Sitophilus zeamais Motschulsky, Coleoptera: Curculionidae) is a key pest of stored grain maize. As an ecological pest control alternative, the use of botanical insecticides, such as powder from boldus (Peumus boldus Molina) foliage singly or mixed with lime, has been evaluated. Unfortunately, its shelf life is very short and does not exceed 15 d. The effectiveness of vacuum storage on insecticidal properties of a natural grain protector produced with boldus powder:lime at proportions of 50:50 and 60:40 against adults of S. zeamais was assessed under laboratory conditions. Treatments were evaluated at 1% and 2% (w/w) for 150 d of storage. All treatments based on boldus powder kept the level of mortality by contact activity over 80% at 150 d of storage. The highest toxicity, as a fumigant, was observed in treatments 50:50 at 2% and 60:40 at 1% and 2% with mortality over 60%. The grain weight loss was less than 1% and seed germination was not affected. With the exception of 0:100 at 2% without vacuum storage, all treatments were repellent to S. zeamais. Vacuum storage extended shelf life of the grain protector for 150 d.

Botrytis cinerea Pers., the causal agent of gray mold, infects more than 200 plant species. This pathogen has traditionally been controlled by fungicides. However, with the increasing demand for pesticide-free foods new control strategies are needed. The objective of this study was to isolate and select grapevine (Vitis vinifera L.) epiphytic yeasts for the biocontrol of B. cinerea in table grapes. Of the total isolated yeasts (n = 256), 32 exhibited mycelial growth inhibition in dual cultures with a halo > 4 mm, and eight of these isolates inhibited > 90% of conidial germination. When evaluating increasing concentrations on conidial germination inhibition, a dose-dependent response was observed with EC90 values from 0.45 x 10(5) to 0.22 x 10(8) cells mL-1. The antagonistic activity of six yeasts against B. cinerea in table grape berries ’Flame Seedless’ increased as the yeast colonization time increased from 1 to 24 h on the berries, resulting in a higher biocontrol activity on B. cinerea. These results show the effectiveness of grapevine epiphytic yeasts as biocontrol agents of B. cinerea on table grapes.

Botrytis cinerea Pers., agente causal de la pudrición gris, infecta a más de 200 especies vegetales. Tradicionalmente, este patógeno ha sido controlado con fungicidas; sin embargo, la creciente demanda de alimentos libres de pesticidas hace necesario el uso de nuevas estrategias de control. El objetivo de este estudio fue aislar y seleccionar levaduras epífitas de vid (Vitis vinifera L.) para el biocontrol de B. cinerea en uva de mesa. Del total de levaduras aisladas (n = 256), 32 presentaron inhibición del crecimiento micelial, en cultivos duales, con un halo > 4 mm y ocho de estos aislamientos inhibieron la germinación de conidias > 90%. Al evaluar concentraciones crecientes de levaduras sobre la inhibición de la germinación de conidias, se observó una respuesta dosis-dependiente, con valores de CE90 de 0,45 x 10(5) a 0,22 x 10(8) células mL-1 Al evaluar la actividad antagonista de seis levaduras frente a B. cinerea en bayas de uva de mesa ’Flame Seedless’ se determinó que al aumentar el tiempo de colonización de las levaduras en las bayas de 1 a 24 h, la actividad de biocontrol sobre B. cinerea fue superior. Estos resultados demuestran la efectividad de levaduras epífitas de vid como agentes de biocontrol de B. cinerea en uva de mesa.

Genotype x environment (G × E) interaction in canola (Brassica napus L.) cultivar seed yield is unknown in Chile. The interaction was performed with the SREG (Sites Regression) model. Two experiments were conducted in five and thirteen environments in the 2008-2009 season in Central South Chile. The experimental design was a randomized complete block (RCBD) in each environment with four replicates and 26 open-pollinated or hybrid canola genotypes in Experiment 1, and RCBD with three replicates and 17 genotypes in Experiment 2. ANOVA was used to determine the significance of the G × E interaction. biplots were used to graphically interpret and determine the best cultivar in each environment and the corresponding mega-environments. The G × E interaction was significant for seed yield in many locations in one cropping season. Most of the analyzed seed yield variation was due to environment and G × E effects. Principal components (PC1 and PC2) of the Sites Regression (SREG) model, with five and eight environments, accumulated 74.5% and 61.1% of the total variation, respectively. Two mega-environments were formed; the first being the Chillán environment while the second included the remaining environments. Six of the evaluated cultivars, all hybrids except ’Goya’, were superior. The mean vs. stability analysis indicated that the Monalisa hybrid had the highest yield and was the most stable cultivar across all environments. Although the information is for only 1 yr, results could change with data from several years of experimentation. Hence, the study was carried out in many locations in order to provide validity to the results.

La interacción genotipo x ambiente en raps (Brassica napus L.) en Chile es desconocida. Para su determinación se utilizó el modelo SREG (regresión de sitios). Dos experimentos fueron establecidos en la temporada 2008-2009. El diseño experimental en cada ambiente fue de bloques completos al azar con cuatro repeticiones y 26 cultivares de polinización abierta o híbridos de raps para el Experimento 1 y de bloques completos al azar con tres repeticiones y 17 cultivares para el Experimento 2. Se utilizó un ANDEVA para determinar la significancia de G × E. Se usó el biplot para la interpretación gráfica y determinación del cultivar superior en cada ambiente y determinar el correspondiente mega ambiente. En una temporada y para las localidades evaluadas la interacción G x E fue significativa para rendimiento de semilla. La variación en el rendimiento de semillas determinada por el análisis fue debido al efecto del ambiente y de la interacción G x E. Los componentes principales (PC1 y PC2) del modelo SREG con cinco y trece ambientes acumularon 74,5% y 61,1% del total de la variación, respectivamente. Se formaron dos mega ambientes, un ambiente representado por Chillán y el otro formado por el resto de los ambientes estudiados. Seis de los cultivares evaluados fueron superiores y todos fueron híbridos excepto ’Goya’. El análisis del promedio vs. estabilidad indicó que el híbrido Monalisa fue el de mayor rendimiento y el más estable evaluado a través de todos los ambientes. La información presentada sólo representa una temporada y podría variar si incluyera información que cubriera algunos años.

The seedling vigor of 80 barley recombinant chromosome substitution lines (RCSLs) was measured for selecting high seedling vigor genotypes. The RCSLs were derived from a cross between H. vulgare subsp. spontaneum and H. vulgare subsp. vulgare 'Harrington'. The work was carried out under greenhouse conditions during the summer of 2008. The experimental design was an alpha lattice with 3 replicates. In each replicate, 40 plants were established, distributed in eight polyethylene pots containing sand as substrate, which were fertilized an irrigated. The emergence of seedlings, number of leaves and shoots, dry matter of leaves, shoots and roots and leaf area of fully expanded leaves were measured. In addition, growth indices were calculated: emergence rate, leaf appearance rate, relative leaf expansion rate, relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR) and the allometric coefficient (K) between root and shoot dry matter. All calculated indices varied significantly among genotypes (P≤0.05) and some RCSLs showed better early vigor associated traits than 'Harrington'. The dry matter accumulation 30 DAS (when the experiment ended) was significant and positively correlated with the RGR (r=0.61; P≤ 0.05) and NAR (r=0.41; P≤0.05). The K coefficient was negatively correlated with NAR (r=-0.40, P≤0.05). The genotypes with the greatest seminal vigor were the RCSLs 45, 92, 112 and 'Harrington', whereas the RCSLs 5, 19, 47 and 121 presented the lowest seminal vigor.

Se estudió el vigor seminal de 80 líneas recombinantes con sustitución de cromosomas (RCSLs), derivadas de la cruza entre H. vulgare subsp. spontaneum y H. vulgare subsp. vulgare 'Harrington'. El trabajo se realizó bajo invernadero durante el verano del 2008. Se usó un diseño experimental de alpha lattice con tres repeticiones. En cada repetición, 40 plantas de cada línea se establecieron en 8 macetas que contenían arena como sustrato. Se realizó 8 muestreos, en los que se evaluó emergencia de plántulas, número de hojas y tallos, materia seca de hojas, tallos y raíces y área foliar de hojas plenamente expandidas. Además, se calculó índices de crecimiento como tasa de emergencia, tasa de aparición de hojas, tasa relativa de expansión foliar, tasa de crecimiento relativo (TCR), tasa de asimilación neta (TAN), proporción de área foliar (PAF) y el coeficiente alométrico de la relación entre materia seca radical y aérea (K). Todos los parámetros variaron significativamente entre genotipos (P ≤ 0,05) y algunas RCSLs fueron superiores a Harrington. La acumulación de materia seca en el último muestreo se correlacionó significativa y positivamente con la TCR (r =0,613; P ≤ 0,05) y la TAN (r=0,414; P ≤ 0,05). El K se correlacionó negativa y significativamente con la TAN (r=-0,393; P ≤ 0,05). Los genotipos con mayor vigor seminal fueron las RCSLs 45, 92, 112 y Harrington; mientras que los con menor vigor seminal fueron las RCSLs 5, 19, 47 y 121.

The objective of this work was to determine the annual variation of Peumus boldus Molina insecticidal properties for the control of Sitophilus zeamais Motschulsky, under laboratory conditions. The powder of P. boldus leaves was evaluated, during 12 months, in 0.5, 1, and 2% (w/w) concentrations. Thirty-six treatments, with three replications, were evaluated in a completely randomized experimental design, with a factorial arrangement. Evaluations were made for adult and immature insect percentage mortality and emergence, grain weight loss and seed germination. The greatest mortality was obtained in August and September 2003, in the three concentrations with 100%, and the lowest mortality was registered in May 2003, when only 2% (w/w) reached almost 100% mortality. The lowest adult insect emergence and weight loss were obtained in the same treatments. The effect on immature stages was lower than on adults; and grain germination was affected by P. boldus powders. Insecticidal properties of P. boldus leaves powder are not stable during the year; May is the month with lesser insecticide efficacy; and the powder affects grain germination.

El objetivo del presente trabajo fue determinar la variación anual en las propiedades insecticidas de Peumus boldus Molina, en el control de Sitophilus zeamais Motschulsky, bajo condiciones de laboratorio. El polvo de hojas de P. boldus se evaluó durante 12 meses, en concentraciones de 0,5, 1 y 2% (p/p). Se evaluaron 36 tratamientos con tres repeticiones, en un diseño experimental completamente al azar, con un arreglo factorial. Se determinó el porcentaje de mortalidad y emergencia de insectos adultos e inmaduros y pérdida de peso y germinación del grano. La mayor mortalidad se obtuvo en los meses de agosto y septiembre de 2003, para las tres concentraciones con un 100%, mientras que la menor fue en mayo de 2003, cuando solo la concentración de 2% fue próxima a 100% de mortalidad. La menor emergencia de insectos adultos y pérdida de peso se obtuvieron en los mismos tratamientos. El efecto sobre estados inmaduros fue menor que contra adultos, y la germinación de los granos de maíz fue afectada por los polvos de P. boldus. Las propiedades insecticidas del polvo de hojas de P. boldus no son estables durante el año, Mayo es el mes con la menor eficacia insecticida, y la germinación de las semillas se ve afectada por el polvo.

Twenty three powdered plants were evaluated under laboratory conditions against Sitophilus zeamais Mots. on stored corn. In the first part of the work all plants were evaluated at a concentration of 1.0% (w/w). Furthermore the powders with best results were evaluated at concentrations of 0.1, 0.5, 1.0 and 2.0% on corn grains infested with insects during 24 hours, 30, 60 and 90 days. Sixty three treatments in a completely randomized experimental design were evaluated and the study was replicated three times. In the first stage the highest level of insect mortality was exhibited with Chenopodium ambrosioides L. and Peumus boldus Mol. at 1.0% concentration (w/w), with values of 65.8% and 99.3%, respectively. The highest insect emergence reductions were obtained with the same treatments and the grain weight was reduced up to 13.0%. In the evaluation with more concentrations, the best results were obtained with treatments at 1.0% and 2.0% (w/w), with C. ambrosioides the insect mortality values were 90.3% and 90.1% and with P. boldus mortalities of 97.1% and 98.8% were achieved. The residual effect lasted up to 24 hours.

Se evaluaron, bajo condiciones de laboratorio, 23 plantas en polvo para el control de Sitophilus zeamais Mots. en maíz almacenado. En una primera etapa se evaluaron todos los polvos a una concentración del 1,0% (p/p). Posteriormente aquellos polvos con mejores resultados fueron probados en concentraciones del 0,1, 0,5, 1,0 y 2,0% en granos de maíz infestados con los insectos a las 24 horas, 30, 60 y 90 días. Se evaluaron 63 tratamientos distribuidos en un diseño experimental completamente al azar y el ensayo se repitió tres veces. En la primera etapa, la mayor mortalidad de insectos se obtuvo con Chenopodium ambrosioides L. y Peumus boldus Mol. con 65,8% y 99,3%, respectivamente. Estos tratamientos también propiciaron la menor emergencia de adultos, mientras que la pérdida de peso de los granos no superó el 13,0%. En las evaluaciones a diferentes concentraciones mostraron una mayor mortalidad y menor emergencia a concentraciones del 1,0% y 2,0% (p/p), obteniéndose para C. ambrosioides una mortalidad del 90,3% y 90,1% y para P. boldus 97,1% y 98,8%, respectivamente. La residualidad se mantuvo sólo en el tratamiento de 24 horas.