Details on the situation of Hercinothrips dimidiatus in Portugal
As reported in the EPPO RS 2015/025, Hercinothrips dimidiatus (Thysanoptera: Thripidae) was detected in Portugal on Aloe arborescens. In October 2014, high levels of infestation were found on plants of A. arborescens in the municipalities of Lisbon, Oeiras and Cascais. These plants were grown in gardens (public and private) and along the roads. Further studies noted that the first damage had been observed in January 2012 on A. arborescens in the gardens of a laboratory in Lisbon. Damage observed was described as follows: ‘the older leaves of the damaged plants were dark brown to almost black. Mature leaves showed silvering areas on the upper surface, associated with small discoloured scarifications and covered with dark coloured excrement droplets, indicating the presence of thrips’. These silvery areas due to thrips feeding activity later develop into larger black necrotic areas. Attacked leaves frequently turn black and die.
A survey was conducted from September 2014 to March 2015 near Lisbon, in public and private gardens, as well as in naturalized plant clusters. As a result, H. dimidiatus was found in other localities around Lisbon (several localities in the municipalities of Lisbon, Oeiras, Cascais, and Sintra), causing damage to A. arborescens plants. All collected adult thrips were females. Results suggest that H. dimidiatus is restricted to an area along the northern river bank of Tagus estuary, between Lisbon and Cascais, and along the Atlantic coast, in the Natural Park of Sintra-Cascais. It is suspected that the pest was introduced by the activities of the Lisbon international maritime port and airport. As very little information is currently available on H. dimidiatus, studies on its life history and its possible interaction with plant pathogens, as well as on the development of effective control measures are being carried out.
Sources
Mateus C, Franco JC, Caetano MF, Borges da Silva E, Ramos AP, Figueiredo E, Mound L (2015) Hercinothrips dimidiatus Hood (Thysanoptera: Thripidae), a new pest of Aloe arborescens Miller in Europe. Phytoparasitica 43(5), 689-692.