Ecological and Biological Aspects of Aphid Parasitoids on Navel Orange Trees in Egypt

The current study aimed to estimate the seasonal abundance of aphid species and their associated parasitoids on navel orange trees across the two seasons of 2021 and 2022 and to evaluate the potential impact of Aphidius matricariae Haliday against Aphis gossypii (Glover) during the period extended from August 2022 to January 2023. The results showed that the major aphid species were A. gossypii, Aphis citricola (van der Goot), Myzus persicae (Sulzer), and Aphis craccivora Koch. Data also revealed that A. matricariae, Trioxys sp., and Praon sp. were recorded as primary parasitoids and Charips sp. as a hyperparasitoid parasitoid. The behavior of A. matricariae varied according to the different host densities, since increased host density led to increased stings and mummies, and decreased leaf arrival times and host arrival times. By rearing A. matricariae on A. gossypii for three successive generations, the sex ratio (females: males) was nearly 1: 1 in the first two generations, but males dominated in the third ones (2.83:1). The obtained results showed that the parasitoid A. matricariae was the most abundant and efficient species and could be included in future biocontrol programs against A. gossypii.