EFFICACY OF CERTAIN PREDATORS IN CONTROLLING APHIDS ON NAVEL ORANGE TREES

Document Type : Original Article

Authors

Plant Protection Research Institute, Agricultural Research Center, Dokki, Giza, Egypt.

Abstract

The aim of this research was to assess the efficacy of some predators worked as a biocontrol tool against the navel orange aphid species (Aphis gossypii (Glover), Aphis citricola (van der Goot), Myzuspersicae (Sulzer), and Aphis craccivora Koch.)during a period of two seasons in 2021 and 2022. Aphis gossypii and Aphis citricolaare the two main species of aphid discovered on navel orange plants. In the two seasons of the study, there were three abundance peaks of Aphis gossypii. In 2021, the numbers recorded in the third week in April and May, as well as the second week in June were 370, 450and 454 individuals/40 leaves and recorded 281,386, and 500 individualsduring the first and fourth weeks of April and the fourth week of May in 2022, respectively. Meanwhile, A. citricola had two abundance peaks in both seasons: in 2021 (181 and 98 individuals/40 leaves) and in 2022 (245 and 295 individuals/40 leaves).Coccinellaundecimpunctata L., ChrysoperlacarneaSteph, C.septempunctata,MetasyrphuscorollaeFandCydoniavicinaisis were the most common predators discovered on navel orange trees.. A few number of Paederusalfierii (Koch) and true spiders were the most common predators caught in navel orange trees. On navel orange trees, these predators recorded two peaks in two seasons (73 and 77 predators/40 leaves) during the first season, and (83 and 88 predators/40 leaves) during the second season, respectively.Two predators, C. undecimpunctata and C. carnea, that prey on A. gossypii were researched from a biological perspective at 21±1°C and 65± 5% R.H. C. undecimpunctataand C. carnea took 23.49 ± 1.40 and 25.01 ± 2.63 days, respectively, to develop from egg hatching to adult exclusion. The total consumption rate per C. undecimpunctata and C. carnea larva fed on A. gossypii were 567.50 ± 6.90 and 587.63 ± 9.27 when fed on A.gossypii. During their larval stages, C. undecimpunctata and C. carnea females generally lay around 315.85±5.17 and 321.52±6.19 eggs.

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