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La polilla del tomate (Tuta absoluta Meyrick; Lepidoptera: Gelechiidae) es una de las plagas más devastadoras del tomate en Colombia y países suramericanos, produciendo pérdidas de hasta el 100% en cultivos sin protección. En 2009, T. absoluta se detectó en España, Portugal y países del mediterráneo, además de Inglaterra, Bulgaria y Alemania. Para su control se utilizan insecticidas químicos que generan resistencia e impacto ambiental y de salud. La alternativa de utilizar biopesticidas contra esta plaga es de importancia creciente. En este estudio se evaluaron cinco métodos de bioensayo para medir adecuadamente la toxicidad sobre larvas de T. absoluta de tres productos comerciales: Dipel®, XenTary® y Turilav®, formulaciones a base de Bacillus thuringiensis (Bt). El método de Inmersión del folíolo, con el producto Dipel®, causó el 100% de mortalidad de larvas y 96% de supervivencia del testigo; este método presentó diferencias significativas al segundo (F=0,025, p>0,05) y cuarto (F=0,0018, p>0,05) día después de la aplicación (DDA). El método de Aspersión foliar por aerógrafo produjo 100% de mortalidad de larvas con Dipel® al segundo DDA (F=7,94x10-10, p> 0,05), y produjo diferencias significativas también al cuarto DDA (F=3,45x10-6, p>0,05). Los métodos Foliolos sumergidos y Medio de cultivo provocaron una alta mortalidad en el control por lo que fueron rechazados. El uso de Dipel®, XenTari® y Turilav® en concentración de 1,25 g/L causó entre 80-100% de mortalidad entre el segundo y octavo DDA en tres métodos evaluados válidos (i, ii, v), además corrobora la actividad biológica de B. thuringiensis sobre este insecto plaga. Palabras clave: Tuta absoluta, Bacillus thuringiensis, Dipel®, XenTary®, Turilav® Abstract: The tomato moth (Tuta absoluta Meyrick; Lepidoptera: Gelechiidae) is one of the most devastating pest of tomato in Colombia and South American countries producing losses of up to 100% on unprotected crops. In 2009, T. absoluta was detected in Spain, Portugal and the Mediterranean countries, besides England, Bulgaria and Germany. For control it chemical insecticides are used, these generate resistance and environmental and human health impact. The alternative of using biopesticides against this pest is of increasing importance. This study evaluated five bioassay methods that properly measure the toxicity on larvae of T. absoluta of three commercial products: Dipel®, XenTary® and Turilav® based formulations in Bacillus thuringiensis (Bt). The method "leaf dipping bioassay" caused with the product Dipel® 100% mortality of larvae and 95% survival of the control group. The other products showed significant differences to 2nd (F=0.025, p> 0.05), 4th (F=0.0018, p> 0.05) day after application (DAA). The "leaf spray airbrush" method used, produced with Dipel® 100% mortality of larvae to 2nd DAA with significant differences with the other products tested (F=7.94x10-10, p> 0.05 ), 4th (F=3.45x10-6, p> 0.05 ) and the 8th (F=1.07x10-5, p> 0.05 ) DAA. Methods "leaflets submerged" and "culture medium" caused high mortality in control being rejected. A variation of the leaflet immersion method was standardized. The three commercial product on concentration of 1.25 g/L produced high mortality in Lab conditions against control of larvae of T. absolute, corroborating the biological activity of B. thuringiensis on this insect pest. Key words: Tuta absoluta, Bacillus thuringiensis, Dipel®, XenTary®, Turilav®

Some insects are important pests in cotton crops and can cause serious yield losses. Among them we can relate Alabama argillacea (cotton leafworm) and Aphis gossypii (cotton aphid), demanding, often, the use of control measures. This study aimed to evaluate the toxicity of Bacillus thuringiensis (Dipel®) to cotton leafworm and analyze its effect on the occurrence of this pest and the cotton aphid in cotton grown under two system of row spacing, in two places in the State of Mato Grosso, Brazil, as well as in some natural enemies. The toxicity was evaluated using doses of 0.30, 0.50, 0.75 and 1.00 L/ha, considering large cotton leafworm larvae (>1.5 cm) and small ones (<1.5 cm) in a laboratory bioassay. The effect of the biopesticide on A.argillacea and A. gossypii was compared in cotton grown in row spacing of 0.90m (conventional) and 0.45m (reduced). The results indicate that: Dipel® has good efficiency for control A. argillacea caterplillars and is selective for A. gossypii, causing a significant increase in cotton yield; 0.45m row spacing promotes a decrease in density of larvae of A. argillacea and A.gossypii, and yield is similar in both spacing, 0.90 and 0.45m, and bigger in treated areas. [ABSTRACT FROM AUTHOR]

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The article presents a study which investigates the effect of Bacillus thuringiensis (Bt) on foraging behaviour, reproduction, and survival in bumblebee Bombus terrestis (L.) using two Bt strains and laboratory microcolonies. It reveals that the strains did not affect the insects' foraging behaviour, reproduction, and survival, but they have detrimental affects when put in feeding sugar water. It concludes that the strains are safe to the bees, although they have damaging effects in some cases.