Quantitatively Disturbed Larval Haemogram of Galleria mellonella L. (Lepidoptera: Pyralidae) by Certain Plant Growth Regulators

K., Ghoneim,; Kh., Hamadah,; A., El-Hela,; A., Abo Elsoud, A.

doi:10.21608/eajbsa.2023.284942

Quantitatively Disturbed Larval Haemogram of Galleria mellonella L. (Lepidoptera: Pyralidae) by Certain Plant Growth Regulators

Document Type : Original Article

Authors

¹ Department of Zoology and Entomology, Faculty of Science, Al-Azhar University, Cairo, Egypt.

² Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt.

10.21608/eajbsa.2023.284942

Abstract

The greater wax moth Galleria mellonella L. (Lepidoptera: Pyralidae) is distributed in different parts of the world. Because of the voracious feeding of larvae and their tunnelling behaviour, this pest destructs the honeycomb and other bee‐hive products. The objective of the present study was to evaluate the impacts of the plant growth regulators (PGRs), viz., indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), 2,4-Dichlorophenoxy acetic acid (2,4-D) and 6-benzyladenine (6-BA), on the important quantitative characters of the larval haemogram, viz., total hemocyte count (THC) and differential hemocyte counts (DHCs). For this purpose, the 3^rd instar larvae were force-fed on diet mixed with LC₅₀ of each PGR (0.24, 0.022, 0.16 & 0.085 ppm, respectively). The haematological investigation was conducted in haemolymph of the 5^th and 7^th (last) instar larvae. The important results could be summarized as follows. Five main types of freely circulating hemocytes in the haemolymph of the 5^th instar and 7^th (last) instar larvae had been identified as Prohemocytes, Plasmatocytes, Granulocytes, Spherulocytes and Oenocytoids. The THC in haemolymph of control larvae slightly decreased with the instar. The feeding of 3^rd instar larvae on diet mixed with IBA, 2,4-D, or 6-BA resulted in increasing THC in haemolymph of 5^th instar larvae. Also, IAA, 2,4-D and 6-BA promoted 7^th instar larvae to produce considerably increasing THC. In contrast, IAA exhibited a slight reducing effect on 5^th instar larvae, since decreasing THC was counted. Also, IBA exerted a suppressing action on larvae to produce normal THC in 7^th instar larvae. The tested PGRs exerted diverse actions on DHCs since no certain trend was detected in the fluctuated hemocyte populations. Moreover, some of the PGRs failed to affect the DHCs of certain hemocyte types. However, the auxin PGR, IAA and IBA, may be effective agents in the IPM program against G. mellonella.

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