Damage in Rosa sp. associated with thrips infestation and sticky traps for monitoring of resident and immigrant thrips populations at Bogotá Plateau (Colombia)

A longitudinal study that assessed the relationship between thrips infestation and damage in two varieties of Rosa sp., in plastic greenhouses of Colombia is presented. Direct sampling on plants for thrips adults and larvae was done for 36weeks to determine their distribution and population density. Thrips feeding damage in leaves and flowers was assessed for 13weeks during harvest. Thrips were sampled with Horiver® sticky traps in the crop, in the central roof vents 7m above the crop and at 5m from the two main entrances of the greenhouse for 36weeks. Frankliniella occidentalis was the dominant species (N=21,729,77%), and Thrips tabaci was also found. The spatial analysis using SADIE-Epiphy based on direct sampling showed an aggregate and structured distribution (I<1.5) with patches of high density of thrips as sources of dispersion within the greenhouse. A main and permanent hot spot was identified at the north-west portion of the greenhouse. This hot spot appeared to be maintained through thrips immigration from external sources located nearby as was suggested by data from external and indoor roof vents sticky traps. Damage in leaves was correlated with total thrips counts (R²=83.1%,F=54.184 p=0.0). A weak but significant correlation (R²=31.9%,p=0.017) was found between the number of thrips in traps and direct sampling for all quartiles. The monitoring and management of thrips should be focused on the points of original infestion and in accordance with the high-density of thrips as an early warning to detect dispersion through models incorporating intersection zones.