Within-plant distribution and seasonal population dynamics of flower thrips (Thysanoptera: Thripidae) infesting French beans (Phaseolus vulgaris L.) in Kenya

Abstract

The aim of this research was to study spatial distribution of flower thrips on French beans (Phaseolus vulgaris L.) in Kenya. Their build up and seasonal population dynamics was monitored using sticky blue colour traps and sampling of leaves and flowers in two seasons in 2002. Thrips infested French beans from the second week after crop emergence. Their population peaked at peak flowering. The sticky trap catches were linearly related to the actual presence of thrips on the crop and could estimate population build up of adult thrips on leaves and flowers. On the plants, most adults were on flowers. Larvae mainly inhabited leaves, buds and pods. The two thrips species, Frankliniella occidentalis (Pergande) and Megalurothrips sjostedti Trybom were spatially separated. The former colonized lower-canopy leaves and early flowers while the latter inhabited middle-canopy leaves and mature flowers. Overall, M. sjostedti was less than 5% of the total thrips population, implying that F. occidentalis was the main thrips pest of French beans. This study suggests that French bean growers should monitor thrips population before initiating any control measure. In addition, they should commence thrips control early, at pre-flowering, using larvicides to reduce the thrips pool and their migration to flowers. A combination of monitoring with sticky traps and proper sampling would contribute to sustainable thrips management.

Stability and extent of resistance of cowpea lines to flower bud thrips in Uganda

“…1B, 2B, 3B), depending on genotype, which coincided with the peak of flowering in all the cultivars. Several authors had observed such trends in flower thrips population under natural infestation in Kenya (Kasina et al, 2009;Nyasani et al, 2013).…”

Effectiveness and profitability of insecticide formulations used for managing snap bean pests

“…Bean fly damage may result in seedling death under severe infestation (Abate and Ampofo, 1996). In contrast, flower thrips start infesting at the vegetative stage and migrate later into flower buds and flowers (Kasina et al, 2009). Thrips infestation levels were higher in snap beans planted in the first dry season (January 2002) than in the second dry season (July 2002) in MweaTebere (Kasina et al 2009).…”

“…In contrast, flower thrips start infesting at the vegetative stage and migrate later into flower buds and flowers (Kasina et al, 2009). Thrips infestation levels were higher in snap beans planted in the first dry season (January 2002) than in the second dry season (July 2002) in MweaTebere (Kasina et al 2009). Damage by flower thrips results in premature fall of flower buds and flowers.…”

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

“…Igualmente, se presentaron diferencias significativas en la comparación entre los promedios de la densidad poblacional del trips de acuerdo a su estado de desarrollo de ninfa y adulto con cada estructura, lo que evidenció que tanto adultos como ninfas del insecto también se encuentran en mayor numero en los terminales. Algunos trabajos realizados sobre trips registran que la mayor incidencia de este insecto se observa cuando la planta llega o está en periodo de floración (Ávila Quezada et al, 2002;Urías-López et al, 2007;Kasina et al, 2009). Sin embargo, estos estudios no describen en que parte de la planta el insecto se ubicó después de que hizo su aparición.…”