A field study on the biology of the purple scale, Lepidosaphes beckii (Newman) (Hemiptera: Diaspididae) on citrus trees in Mazandaran, Iran

The purple scale, Lepidosaphes beckii (Newman) (Hemiptera: Diaspididae), is one of the important citrus pests in Mazandaran Province, north ofIran. The bioecology of this pest was studied on citrus trees (Citrus aurantium) in citrus orchards of Mazandaran during 2018 and 2019. The results showed that this scale insect produces three generations per year and overwinters in the form of the second nymphal instars and adult females. A study on population flactuations revealed that the first generation of this pest, depending on the weather conditions, has been active since late May and its growth stages were completed in the first decade of August. Afterwards, the activity of the second generation begins and the first instar nymphs related to the second generation appear in the second decade of August. The activity of the third generation begins in the first decade of October. The crawlers disperse at the same time and the armored scale overwinters in the form of second nymph instars and adult females after establishing and completing growth. The trend of population fluctuations on the upper and lower of the leaves was similar. The activity of parasitoids was observed mainly on adult females in April to May and July to October, but the peak of their activity was in April to May.