Flower thrips Frankliniella occidentalis (P.) may cause severe economic losses due to its periodic occurrence, the damage caused by sucking sap and spreading plant diseases through the transmission of viruses, mainly in horticultural crops and ornamental plants, such as roses, gerbera and carnation. Monitoring through sticky colored traps provides a simple method of obtaining estimates of thrips population densities. These traps may measure a far more rapid estimate of pest population than labor-intensive absolute methods of counting individuals, as these traps continuously catch a higher number of thrips throughout the time. The utility of these sticky colored traps methods as tools for monitoring thrips population has been assessed in greenhouses, taking into consideration the traps attractiveness and the capture rate according to species. This work was conducted once a serious damage on flowers (Frankliniella occidentalis) caused by thrips was observed, mainly in a Gerbera jamesonii crop located in a greenhouse for cut flowers production in the Argentine Agricultural Experiment Station (EEA) of the National Institute for Agricultural Technology (INTA) of Concordia, Province of Entre Rios (Argentina). The main purpose of this work was to evaluate the effectiveness of sticky light traps of two colors (yellow and blue, both of them selected due to its known attractiveness to various thrips species and different light intensities (25 and 40 watt bulb)) on the capture of flower thrips. These traps were made from cardboard boxes (22 x 30 x 20 cm) with an opening (10x15 cm) through which light passes and covered with a plastic wrap coated with adhesive material on which the adults thrips become trapped (The Tanglefoot Company Adhesive Pest Management & Tree Protection Products, USA). The trial consisted of the following four treatments: (i) yellow light trap with 25 watt bulb; (ii) yellow light trap with 40 watt bulb; (iii) blue light trap with 25 watt bulb and (iv) blue light trap with 40 watts bulb. Each treatment was replicated four times. Four sticky light traps were positioned on both sides of the Gerbera jamesonii flowerbeds to half-height of cut flowers. For each trial, the trap placement in each experimental design was at random. The bulbs were turned on at sunset and turned off in the morning when the traps were removed and carried to the laboratory and the number of adult thrips caught was counted. On the one hand, yellow light traps with both intensities (25 and 40 watt bulbs) became significantly more attractive to F. occidentalis adults in comparison to the capture rate on the blue ones with the same intensity; and, on the other hand, both yellow and blue sticky light traps were much more efficient for the capture of thrips F. occidentalis with 40 watt intensity bulbs. One reason why thrips would respond to various visual stimuli (a more effective response to w color and its high intensity) would be related to its response to the different changes of physiological features of plants. These changes would play a significant important role in sending a visual signal (color and intensity), which would lead Frankliniella occidentalis (P.) to change the search behavior as to its feeding sources and oviposition.
El trips de las flores Frankliniella occidentalis (P.) es, sin dudas, uno de los insectos del orden Thysanoptera de mayor peligrosidad en el mundo, ya que produce importantes pérdidas económicas. Esto se debe a su periódica aparición y al daño que ocasiona, tanto por la extracción de savia como por la transmisión de enfermedades virósicas, principalmente en cultivos hortícolas y plantas ornamentales tales como rosa, gerbera y clavel. El monitoreo con trampas adhesivas de color proveen un método simple para estimar la densidad poblacional del trips con poco esfuerzo. Las mismas pueden medir poblaciones de la plaga más fácilmente que los métodos absolutos de monitoreo con uso intensivo de mano de obra, ya que continúan capturando en el tiempo mayor cantidad de trips. La efectividad del uso de trampas adhesivas de color como herramienta para monitoreo de trips ha sido evaluada en invernáculos estando condicionado al atractivo de las trampas y a las tasas de captura de trips según la especie. Al observarse un importante daño de trips, predominantemente en las flores en un cultivo de Gerbera jamesonii ubicado en un invernáculo de producción de flores de corte de la EEA INTA Concordia, provincia de Entre Ríos (Argentina), se inició el presente trabajo cuyo objetivo fue evaluar la efectividad de trampas de luz adhesivas de dos coloraciones (amarillas y azules, ambas seleccionadas por su reconocida atracción a diferentes especies de trips y con diferentes intensidades de luz (25 y 40 watts) sobre la captura de trips de las flores. La unidad muestral fue la trampa de luz, mientras que los tratamientos fueron: color de la trampa de luz (amarilla y azul), a dos intensidades distintas (25 y 40 watts), siendo por cada tratamiento un total de cuatro repeticiones. Las trampas de luz adhesivas fueron dispuestas en los canteros de Gerbera jamesonii, a razón de cuatro por cantero a los lados de los mismos, a la altura media de las flores de corte. La disposición de las trampas de cada tratamiento en la parcela experimental fue al azar. Las lámparas eran encendidas al atardecer y apagadas por la mañana, momento en que se llevaban al laboratorio con el fin de contabilizar el número de trips adultos capturados. Las trampas de luz amarillas de ambas intensidades (25 y 40 watts) resultaron ser significativamente más atractivas para la captura de adultos de F. occidentalis en comparación con las de color (azul) e igual intensidad. Por otra parte, las trampas de luz adhesivas indistintamente de su color, tanto amarillo como azul, resultaron ser significativamente más eficientes en la captura del trips F. occidentalis cuando las lámparas poseían una intensidad de 40 watts.
