Colonization of growing fruit by the armored scales Lepidosaphes beckii, Parlatoria pergandii and Aonidiella aurantii (Hom., Diaspididae)

Abstract

Abstract: The process of invasion of the fruit surface by three species of armored scale insects [Lepidosaphes beckii (Newman), Parlatoria pergandii Comstock and Aonidiella aurantii (Maskell)], was studied in citrus orchards in València, Spain. Three periods of intense crawler migration were detected annually for L. beckii and P. pergandii. Abundance of crawlers increased throughout the year and they moved outwards in the tree canopy. The fruit was continuously invaded during the period of fruit growth, starting at a very early stage of fruit development, by crawlers of the first generation of all the three species. Differences in fruit invasion and settling behaviour were found between the three species. First‐generation crawlers tended to settle under the fruit calyx in L. beckii and P. pergandii, and on the exposed fruit surface in A. aurantii. During the second generation, most A. aurantii scales originated from reproducing females already settled on the fruit, whereas in L. beckii and P. pergandii new scales came preferentially from other tree substrates or from females settled under the fruit calyx. These findings suggest changes to optimize the timing of chemical sprays for controlling the scales.