Diffusion of secondary insect pest species of citrus in Italy

The increasing diffusion of citrus pests in Italy in the last decades justified the adoption of a careful surveillance/monitoring system. Starting from summer 2008 in the framework of a standard pest monitoring program for the main citrus pests, the insurgence of several infestation of a xylophagous insect has been observed on lemon trees in the coastal area of the Etna district; the pest was identified as Apate monachus (Fabricius) (Coleoptera, Bostrichidae). It attacks several host plants including citrus and produces holes and galleries in the branches, in some cases it induces a gummosis. In many cases the infestation started from plants affected by diseases or badly cultivated. The endophyte behavior of the pest makes it difficult to control it by means of traditional pesticides. In the summer 2012 the diffusion of this pest was also recorded in some sites of the internal area of the Etna district, specialized in the blood and Navel orange cultivation. In the same period, along the Ionian coast of Sicily, several citrus orchards resulted infested by two scale insects: the pyriform scale Protopulvinaria pyriformis (Cockerell) (Hemiptera, Coccidae) and the Florida red scale Chrysomphalus aonidum (Linnaeus) (Hemiptera, Diaspididae). The first one, already reported in Italy mainly on ornamentals (i.e. Laurus nobilis, Eugenia myrtifolia, Schefflera arboricola, etc.) and on other fruit crops (e.g. avocado) was detected on lemon and on Valencia and blood sweet orange. This polyphagous species produces abundant honeydew, and sooty mould develops subsequently reducing photosynthesis and resulting in the loss of the aesthetic value of the fruits. In relation to the Florida red scale, it was also detected in both sweet orange and lemon orchards in the surrounding areas of Messina and Catania provinces as well as on ornamental citrus planted along the main roads of the aforementioned cities. The species feeds on almost all the parts of the host plant causing damage by sap sucking and affecting the commercial value of the fruit. Some data on parasitoids have been recorded. After about five years from their first findings, these pests, were found to infest new cultivated areas and it is possible that they will spread all over the cultivated citrus areas.