The potato tuber moth (PTM), Phthorimaea operculella, is the main potato pest in the world, having managed to adapt to a wide range of climatic conditions, and causing damage to stored tubers. The effectiveness of a biological control using the parasitoid Trichogramma cacaeciae and the predatory mite Blattisocius mali was evaluated in PTM under conditions that simulated those of tubers in storage. The number of adults found at the end of the trial was significantly higher in the control (181.75 ± 11.00 adults/container) than in treatments where B. mali (24.50 ± 7.22) or T. cacaeciae (102.00 ± 14.61) were released. The biological control’s effectiveness using the Abbot formula was 86.52% for the predator and 43.88% for the parasitoid. In addition, the PTM population data was fitted by logistic models, and the best fit was found for the simple logistic function. Using the data generated from these functions, the control efficiencies for the mite and the parasitoid were 94.85% and 73.77%, respectively. B. mali showed greater potential for being incorporated into integrated PTM management programs than T. cacaeciae. Based on logistic functions, a novel way of estimating the effectiveness of predators and parasitoids is also presented and discussed.

Amblyseius swirskii is a predatory mite that is widely used for biological control in greenhouses. One way this predator is released is in a formulation in slow-release sachets. These sachets are prepared with the predatory mite, the factitious prey mite Carpoglyphus lactis, and a food substrate for the latter. The objective of the present study was to study the effects of microclimatic conditions in this type of formulation on the population dynamics of mites inside the sachets and on the release of predatory mites. These experiments were conducted under laboratory conditions in two trials. The ambient relative humidity affected the water content of the food substrate of the prey mite inside the sachets, with an initial value of 21.49 ± 0.42%, which was reduced to values of 4.7 ± 0.25%, 10.87 ± 1.03% and 17.27 ± 0.82% after 21 days of trials when they were exposed to low, medium and high ambient relative humidity levels, respectively. Relative humidity significantly altered the dynamics of the populations of both species inside the sachets and the exits of the predator from the sachets to the external environment.

Rhynchophorus ferrugineus (Olivier, 1790) is an invasive pest species that constitutes one of the most important problems around the Mediterranean region and has been responsible for the loss of over 100,000 palm trees with an estimated annual cost of EUR several hundred million since its introduction into Europe. Methodological approaches of conservation ecology, such as multidisciplinary modelling, also apply in the management of cultural landscapes concerning ornamental plants, such as palm trees of the area. In this paper, we propose a dynamic model for the control of the red palm weevil, contributing in this way to the sustainability of an existing cultural landscape. The primary data set collected is a sample from the density-time function of a two-cohort pest population. This data set suggests a bimodal analytic description. If, from this data set, we calculate a sample from the accumulated density-time function (the integral of the density-time function), it displays a double sigmoid function (with two inflections). A good candidate for the analytical description of the latter is the sum of two logistic functions. As for the dynamic description of the process, a two-dimensional system of differential equations can be obtained, where the solution’s second component provides the analytical description of the original density-time function for the two-cohort population. Since the two-cohort waves appear in all three cycle stages, this reasoning applies to the subpopulations of larvae, pupae and adults. The model fitting is always performed using the SimFit package. On this basis, a mathematical model is proposed, which is sufficiently versatile to be of help in the control of this pest species in other geographical areas.

Los extractos vegetales foliares han sido usados como plaguicidas y/o repelentes contra bacterias, hongos y artrópodos. La actividad biológica de estos preparados se debe a los metabolitos secundarios (MS), compuestos que las plantas sintetizan y cuya concentración varía aún en sus órganos. Se determinó por cromatografía de capa fina la concentración de los grupos de MS en extractos etanólicos (EE) obtenidos a partir de hojas de orégano (Lippia origanoides K.) y citronela (Cymbopogon citratus D.C.) y se evaluó el efecto de los mismos sobre Rhyzopertha dominica (F.) a las concentraciones de 40, 60, 80, 85 y 95% para ambos EE, en un diseño completamente al azar con arreglo factorial 2x5. El estudio fitoquímico permitió determinar la presencia en los EE de orégano y citronela, de aceites esenciales, saponinas (2,02 mm y 3,46 mm), alcaloides (0,0975 y 0,1223 uL/mL), fenoles (0,0899 y 0,11375 uL/mL) y flavonoides (0,1055 y 0,1312 uL/mL), respectivamente. Se presentaron además diferencias signifi cativas (P < 0,01) entre las concentraciones evaluadas, obteniéndose al 95% valores de mortalidad de 56,75%. De igual modo, se presentaron diferencias significativas entre la mortalidad ocasionada por ambos EE (P < 0,05), donde el porcentaje de mortalidad a la concentración de 60%, fue mayor con el EE de orégano (35,5%) que con el de citronela (16%), mientras que a dosis mayores, la efectividad de éste último fue siempre superior a la de orégano. Los MS en los EE resultaron efectivos ocasionando valores aceptables de mortalidad en R. dominica, a altas concentraciones, recomendándose su uso como control preventivo.

Con la finalidad de conocer las especies de trips y ácaros presentes en cultivos comerciales de fresa, se realizaron estudios en las localidades de Bailadores (estado Mérida), Cabimbú (estado Trujillo), La Colonia Tovar (estado Aragua), Cubiro, Paso Real, Páramo Abajo y Tarabana (estado Lara), en Venezuela. En el campo, se examinaron brotes foliares, hojas, botones florales, flores y frutos, para colectar inmaduros y/o adultos de trips y/o ácaros en diferentes cultivares de fresa. En el laboratorio, los trips y/o ácaros en estado inmaduro, fueron criados hasta la fase adulta. Los especímenes adultos fueron montados en láminas microscópicas, etiquetados y depositados en la colección de insectos del Museo de Entomología José M. Osorio (MJMO) de la Universidad Centroccidental “Lisandro Alvarado” (UCLA). De la revisión taxonómica realizada, fue posible identificar las especies Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) y Tetranychus urticae Koch (Acari: Tetranychidae). El reporte de estas especies en cultivos de fresa, constituye nuevos registros para Venezuela.