A traça-verde (Palpita vitrealis (Rossi)) nos olivais da Beira Interior-Sul e o seu impacte em diferentes cultivares

Abstract

In order to control the Jasmine Moth, Palpita vitrealis (Rossi), the population evolution was studied in several olive cultivars (‘Arbequina’, ‘Cobrançosa’, and ‘Galega Vulgar’) located in an olive grove in Quinta do Galvão in Cova da Beira. The young larvae feed on the leaf underside and as they grow consume whole leaves and shoots. The second generation feed on fruit and seeds if high levels of population are achieved (Grossley, 2000). The larvae development is not well synchronised and is temperature-dependent, resulting in the simultaneous presence of eggs, different larval stages, pupae, and adults throughout the season (López-Villalta, 1999). This grove was monitored from March to November 2010, registering catches by traps baited with sex pheromone and observing shoots attacked using the risk assessment according to the national standards of integrated pest management. These data were compared with catches in various regions in the country collected through similar methodology. It was requested data of catches of P. vitrealis in these three warning stations (Baixo Alentejo, Ribatejo, and Beira Interior-Sul), due to low catches recorded in the olive grove of Cova da Beira, in order to compare the pest flight curves from various regions of the country. In the olive grove of Cova da Beira it was found that the cultivar 'Cobrançosa' was the least attacked (90.9 shoots attacked on average). Apparently, this value was not due, to differences in the cultivar leaf thickness. It was also observed low catches of Jasmine Moth (0-8 catches per week) in Cova da Beira, Beira Interior Sul, and Ribatejo, although in Baixo Alentejo it was referred high flight peaks (about 50 catches in some weeks) by the official agricultural advisory services. A contaminant morphotype was caught in the pheromone traps at Cova da Beira but a specific identification was not achieved yet. Three different brands of sex pheromones (Biosani, AT&F, and Russell) were used to test their efficacy and potential. It was concluded that the AT&F sex pheromone revealed some potential, since it was the only one that obtained pest catches at the beginning of autumn, with rather low temperatures.