Four-year flight dynamics of Tuta absoluta in Sicily and implications for IPM strategies

The South American tomato pinworm, Tuta absoluta (Lepidoptera: Gelechiidae), was firstrecorded in Sicily during fall 2008, on tomato and eggplant protected crops. Soon after this report,several control measures were defined in the framework of Integrated Pest Management (IPM)strategies. To this aim, investigations have been carried out to acquire data on the pest populationdynamics in open field through the study of the male flight trends. From April 2009 to May 2012,pheromone traps (Delta type) and digital temperature and humidity loggers were installed in sixhorticultural areas located in Western Sicily, Catania and Ragusa provinces. The selection of themonitoring sites was based on the presence of tomato cultivations and on the different ecological traitsof the neighbouring areas. In the meantime, periodical surveys were also performed on nearby tomatocrops in order to evaluate the pest infestation levels and the presence of natural enemies. The datashowed that the flight activity of T. absoluta males throughout the four-year investigation period wascontinuously observed in all the monitoring stations and it showed typical peaks of high and lowcapture levels during late summer and late winter, respectively. The trend on the captures are nothomogeneous among the studied sites and they varied significantly in function of the thermalextremes, the neighbouring ecological conditions and the availability of more susceptible plants,particularly tomato crops. Indeed, the moth flights, recorded in one site characterized by open fieldhorticulture (Catania), were significantly lower, likely owing to the higher level of crops diversity andof biocontrol agent’s activity, notably by the mirid predator Nesidiocoris tenuis. Overall, the obtaineddata show that the flight activity has slightly decreased during the four years of investigation and it isnoteworthy that the pest infestation level on tomato cultivations in open field and even in protectedcrops is considerably declining. This tendency, recently observed also in the Western Mediterraneancountries, can be attributed both to the adaptation of indigenous natural enemies as well as to theimproved IPM strategies against the exotic pest. These latter are currently based on pest monitoringand they include mass-trapping techniques, application of highly selective insecticides, such asmicrobial products and rational habitat management aimed to enhance conservation biocontrol. Theinformation acquired during the four-year observations provide useful indications for the correctunderstanding of male captures allowing to adapt the data to the different agro-ecological conditions.