A Study on the Biology of the Globular Mealybug, Pollinia pollini Costa on olive trees, Olea europaea L. and its geographical distribution in the western region of Libya

Abstract

This study was carried out during 2022 in an olive field at the Agricultural Research Center Research Station, Tripoli, Libya, to investigate the biology and ecology of the globular mealybug Pollinia pollini (Costa) (Hemiptera: Asterolecanidae), an economic insect pest of olive trees in Libya. Samples were collected from 20 trees every two weeks. In addition, this study aimed to investigate the geographical distribution of the insect in olive growing areas in the western region of Libya, and monitor the population dynamics of P. pollini nymphs and adults during the year, and the number of generations/year. The study showed that the insect is widespread in the regions of Tripoli, Raqdalin, Zaltan, Zuwara, Sorman, Al-Zawiya, Al-Qarbouli, Souq, Al-Ahad, Tarhuna, Masalata, Al-Khoms, Gharyan and Al-Asabaa, while it was not recorded in the regions of Al-Qalaa, Dhaher Al-Jabal, Yafran, Al-Rayina, Al-Rojban and Jadu. The highest density of nymphs was recorded in September, with 960 nymphs/20 samples, whereas the lowest density was recorded in January, with 186 nymphs/20 samples. The highest density of the adult insect was recorded in February with 933 insects/20 samples, whereas the lowest density was in May with 164 adults/20 samples. The study showed that the insect has two generations during 2022, and it was most active in the spring and summer. The results obtained showed that temperature and relative humidity had an effect on insect activity, and the correlation was positive for nymphs and negative for adults, reaching values of 0.544 and -0.762, respectively.

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Keywords:

Libya, globular mealybug, Pollinia pollini, olive, generations.