The efficiency of several sampling methods for Frankliniella occidentalis (Thysan., Thripidae) in strawberry flowers

Abstract

Methods for sampling western flower thrips Frankliniella occidentalis (Pergande) (Thysan., Thripidae) in strawberry flowers were evaluated in three commercial plots by monitoring the population densities of adult and immature thrips throughout the growing season. Three types of flowers were sampled: open, senescent and petal fall, and three procedures were compared: a visual examination of flowers, a turpentine-funnel method and a shake method. Open flowers showed higher population densities of adults, whereas senescent or petal fall flowers had a higher number of eggs and more damage symptoms. Seasonal changes in population density were similar for the three sampling procedures, although the turpentine method recovered more insects, especially larvae, than the other two methods. The turpentine procedure was the most efficient as it extracted almost 100% of adults and, in plots with no chemical sprays, nearly 100% of second instars and 50% of first instars. Regular control of thrips with pesticides reduced the percentage of larvae recovered with this procedure. The visual method spotted 80% of adults and 33% of larvae. The shake method extracted nearly 80% of adults but only 18% of larvae. The visual method is recommended for routine field samplings, especially for sampling adults and in plots regularly sprayed with pesticides, as it constitutes a cost-effective method when time and efficiency are considered.

Distribution of Aeolothrips intermedius Bagnall (Thysanoptera: Aeolothripidae) and its potential prey Thysanoptera species on different cultivated host plants

“…This mixture helps to distend the body of most thrips and keeps the limbs supple. Stored specimens were transferred to 60% alcohol and kept in the dark at the temperature about 0°C to prevent loss of colour (Palmer et al 1989;Mound and Kibby 1998;Gonzalez-Zamora and Garcia-Mari 2003).…”

Caracterização das injúrias causadas por Frankliniella occidentalis no morangueiro

“…No caso da videira, a oviposição dos tripes, nas bagas em formação, durante o período da floração, causa a mancha areolada (BOTTON et al, 2007). Em morangueiro, a alimentação e a oviposição endofítica dos tripes nas flores provocam bronzeamento, seguido de murchamento prematuro e nos frutos a alimentação do inseto está associada a um acastanhamento no receptáculo, ao redor dos aquênios, sendo essa característica variável conforme a cultivar (GONZALEZ-ZAMORA & GARCIA-MARI, 2003).…”

Propuesta de muestreo para Neohydatothrips signifer (Thysanoptera: Thripidae) en el cultivo de maracuyá

“…El conteo se hizo sobre los terminales vegetativos de la planta, habiéndose discriminado el trips por su estado de desarrollo de ninfa o adulto. Para el muestreo, se utilizaron dos procedimientos: golpeo, que consistió en sacudir tres veces cada uno de los terminales de la planta sobre una cartulina de color blanco, en que todos los trips fueron contados; y "visual", a través de lo cual el terminal vegetativo fue cuidadosamente examinado in situ, para contar los trips observados (González-Zamora & Garcia-Marí, 2003). Los muestreos se realizaron durante el segundo semestre de 2009 y el primero de 2010, desde el establecimiento del cultivo hasta las primeras cosechas.…”

“…Para hacer uso del NDE, es necesario estimar la densidad poblacional de la plaga en el cultivo, para lo cual se requieren métodos eficaces y precisos de muestreos en campo, sin incurrir en costos excesivos (González-Zamora & Garcia-Marí, 2003;Kovanci et al, 2005). Desarrollar métodos de muestreos en insectos plagas es dificultoso ya que es necesario el conocimiento previo de algunos parámetros ecológicos de la población, como lo son la distribución espacial y la fluctuación poblacional, entre otros (Ramírez-Dávila et al, 2002).…”