Compatibilidad in vitro de un bioplaguicida a base de Lecanicillium lecanii (Hypocreales: Clavicipitaceae) con agroquímicos empleados en los cultivos de algodón y berenjena / In vitro compatibility of the biopesticide based on Lecanicillium lecanii (Hypocreales: Clavicipitaceae) with agrochemicals used in cotton and eggplant crops

El aislamiento colombiano de Lecanicillium lecanii Vl026 formulado como un granulado dispersable WG, ha demostrado una alta eficiencia para el control de Bemisia tabaci en los cultivos de algodón y berenjena. Teniendo en cuenta el potencial de este bioinsumo, el objetivo del siguiente fue determinar la compatibilidad in vitro del bioplaguicida a base de L. lecanii con agroquímicos (insecticidas y fungicidas) que se utilizan con mayor frecuencia en dichos cultivos. La compatibilidad in vitro se estableció determinando el porcentaje de germinación (%) y las Unidades Formadoras de Colonia (UFC) en presencia de los plaguicidas y estimando la concentración inhibitoria 10 (CI10). Cada plaguicida se evaluó a la dosis recomendada, a la mitad y a un cuarto de ésta. Los fungicidas químicos (Benomil®, Vitavax®, Ridomil® y Manzate®) no fueron compatibles con L. lecanii, ya que inhibieron la germinación y las Unidades Formadoras de Colonia del hongo en las tres dosis evaluadas. En cuanto a los insecticidas químicos, el producto Confidor® no inhibió la viabilidad en comparación con el tratamiento control, considerándose compatible con el bioplaguicida. Cuando se evaluó la dosis completa de los demás insecticidas (Oportune®, Actara®, Match® y Malathion®) se obtuvieron germinaciones inferiores al 80%, por lo que dichos productos se clasificaron como no compatibles con el bioplaguicida a base de L. lecanii. El único agroquímico que fue compatible en condiciones in vitro con L. lecanii fue el producto Confidor®. Sin embargo, se recomienda evaluar el efecto in vivo de los productos químicos habitualmente utilizados por los agricultores sobre L. lecanii, con el propósito de desarrollar y establecer estrategias de manejo integrado de la mosca blanca Bemisia tabaci.

A colombian isolate of Lecanicillium lecanii formulated as dispersible granules WG, has shown high efficiency to control Bemisia tabaci in cotton and eggplant crops. Considering that, the objetive of this work was to determine the in vitro compatibility of biopesticide based on L. lecanii with agrochemicals (insecticides and fungicides) that are most frequently used in tobacco and eggplant crops. In vitro compatibility of L. lecanii with agrochemicals was determinated by germination (%) and Colony Forming Units (CFU) in the presence of pesticides and also estimating the inhibitory concentration 10 (IC10). Each agrochemical was evaluated at the recommended dose, a half and a quarter of it. For the three doses tested (Benomyl®, Vitavax®, Ridomil® and Manzate®) were not compatible with L. lecanii, because these inhibited germination and Colony Forming Units of the fungus. Confidor® did not inhibit viability compared to control treatment, and it was considered compatible with the biopesticide. When the recommended dose (Oportune®, Actara®, Match® and Malathion®)was used, the germination of the L. lecanii was lower than 80%, then these products were classified as non-compatible with the biopesticide based on L. lecanii. The only agrochemical that was compatible in vitro with L. lecanii was Confidor®. However, is necesary to evaluate the in vivo effect of agrochemicals commonly used by farmers on L. lecanii, in order to develop and establish integrated management strategies for the control of the whitefly Bemisia tabaci.

Mating disruption of Guatemalan potato moth Tecia solanivora by attractive and non-attractive pheromone blends.

The behavioral mechanisms of mating disruption in Guatemalan potato moth Tecia solanivora were studied using the sex pheromone components, (E)-3-dodecenyl acetate, (Z)-3-dodecenyl acetate, and dodecyl acetate, formulated in a 100:1:20-ratio mimicking the female-produced blend, and in a 100:56:100 off-blend ratio. The mode of action of these two blends was tested in mating disruption experiments in the field and in a greenhouse, as well as in a laboratory wind tunnel. Field treatments with both blends at 80 g pheromone per ha reduced male attraction to trap lures baited with 100 µg of female sex pheromone. In mesh-house treatments, these two blends were equally effective at reducing male attraction to traps baited with live females and mating of caged females. Subsequent flight tunnel tests corroborated that both blends reduced attraction of naive males to calling females, and pre-exposure of males with either dispenser blend for 24 hr resulted in a strongly reduced response to calling females. The pre-exposure effect was reversible, with males again responsive after 24 hr in clean air. The two dispenser formulations produced a similar effect on male behavior, despite the differences in blend composition. One mating disruption dispenser formulated with either the female-blend or off-blend elicited the same rate of male upwind attraction in a wind-tunnel bioassay. Sensory overload and camouflage, therefore, are contributing mechanisms to mating disruption using either blend. The off-blend, which is more economical to synthesize, is a valuable tool for further development of mating disruption against this major pest of potatoes in Latin America.