Effects of sublethal azadirachtin exposure to the biological performance of Tetranychius urticae Koch was studied under laboratory conditions. Bioassay was used to asses the effect of different concentrations of azadirachtin on longevity, fecundity, fertility, and offspring development. Azadirachtin (64 and 128 ppm) affected fecundity and mortality but had no effect on fertility and offspring development. A subsequent life-table study with 80 ppm of azadirachtin found that the compound caused a reduction of 50% in survival to adult stage. The peak of reproduction was reached at 5 days causing a decrease in the mean fecundity to almost eight times than of untreated females. The net reproductive rate (R0), the intrinsic rate of increase (r(m)), and the finite rate of increase (lambda) of treated females were lower. Treatment showed a negative value of r(m), resulting in a declining population. These results suggest that azadirachtin could be incorporated in Integrated Pest Management (IPM) programmes of T. urticae.

The effect of the chitin synthesis inhibitor lufenuron was evaluated against different developmental stages of Lobesia botrana Den. & Schiff. (Lepidoptera: Tortricidae). Lufenuron fed to adults at 10 ppm reduced their fecundity and fertility, but it did not affect adult longevity. High activity was observed against L. botrana eggs with greater effect on 1-d-old eggs than on the other age classes and on eggs treated by direct contact rather than those laid on a previously treated surface. Eggs laid by treated adults showed the same effects during development as eggs treated by contact or those laid on a treated surface. Larvae that emerged from treated eggs could not perforate grape berries. Administered into the diet, lufenuron had a larvicidal effect, resulting in similar LC50 values for different instars: 0.07 ppm for first instars, 0.08 ppm for third instars, and 0.11 ppm for fifth instars. None of the larvae treated with sublethal concentrations throughout their life emerged as adults at the highest concentration (0.08 ppm), and only 70% emerged at the lowest concentration (0.0025 ppm).

Effects of sublethal exposure to triflumuron on the biological performance of the two-spotted spider mite Tetranychus urticae Koch were analysed under laboratory conditions. Survivorship was affected by the compound. Triflumuron caused a reduction both in the percentage of eggs that developed to adults and in the survival of adult stage. Triflumuron also affected the fecundity. The net reproductive rate (R 0), the intrinsic rate of increase (rm), and the finite rate of increase (l) of treated females were lower than in those non treated, resulting in a reduction of population growth. These results suggest that triflumuron could be a valuable addition in integrated pest management programs of T. urticae, although more laboratory, semi-field and field testing is required.Additional key words: benzoylphenyl ureas, intrinsic rate of increase r m , life-table, triflumuron, two-spotted spider mite. ResumenEfecto de una exposición subletal de Tetranychus urticae Koch (Acari: Tetranychidae) al triflumurón sobre sus parámetros biológicos Se analizaron, bajo condiciones de laboratorio, los efectos de una exposición subletal al triflumurón sobre los parámetros biológicos de la araña amarilla Tetranychus urticae Koch. La supervivencia fue afectada por el compuesto. El triflumurón causó una reducción tanto en el porcentaje de huevos que llegaron a adultos como en la supervivencia de los imagos y en la fecundidad. La tasa reproductiva neta (R 0 ), el coeficiente de incremento intrínseco (r m ), y el coeficiente de incremento finito (l) de las hembras tratadas fueron más bajos que en las no tratadas, dando como resultado la reducción del crecimiento de la población. Estos resultados sugieren que el triflumurón podría ser una incorporación interesante en programas de manejo integrado de T. urticae, aunque es preciso desarrollar más experimentos tanto de laboratorio como de semicampo y campo.Palabras clave adicionales: araña amarilla, benzoilfenil ureas, coeficiente de incremento intrínseco r m, tabla de vida.

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The effect of the chitin synthesis inhibitor lufenuron was evaluated against different developmental stages of Lobesia botrana Den. & Schiff. (Lepidoptera: Tortricidae). Lufenuron fed to adults at 10 ppm reduced their fecundity and fertility, but it did not affect adult longevity. High activity was observed against L. botrana eggs with greater effect on 1-d-old eggs than on the other age classes and on eggs treated by direct contact rather than those laid on a previously treated surface. Eggs laid by treated adults showed the same effects during development as eggs treated by contact or those laid on a treated surface. Larvae that emerged from treated eggs could not perforate grape berries. Administered into the diet, lufenuron had a larvicidal effect, resulting in similar LC50 values for different instars: 0.07 ppm for first instars, 0.08 ppm for third instars, and 0.11 ppm for fifth instars. None of the larvae treated with sublethal concentrations throughout their life emerged as adults at the highest concentration (0.08 ppm), and only 70% emerged at the lowest concentration (0.0025 ppm).