تحديد التسلسل الجينومي الكامل والتواجد الموسمي لحشرة التين الشمعية Ceroplastes rusci L وتقييم كفاءة بعض عوامل الادارة المتكاملة في مكافحتها

Complete genome sequencing and seasonal occurrence of the fig wax moth Ceroplastes rusci L., and evaluation of the effectiveness of some integrated management agents in controlling it

Abstract

Laboratory and field experiments were conducted using some integrated pest management (IPM) agents during the fall 2024 and spring 2025 seasons on the wax scale insect Ceroplastes rusci, to evaluate and study their effectiveness. The laboratory study was carried out in the Entomology Laboratory of the Graduate Studies Department, College of Agriculture, University of Kerbala. At the same time, field experiments (spraying and irrigation methods) were conducted in a fig orchard located in Al-Haidariya district, Najaf Governorate, to confirm the results obtained from the laboratory experiments. The same experimental agents were used in both seasons. A field study was conducted on the presence of the wax scale insect C. rusci by conducting a field survey in a fig orchard in Al-Haidariya district, Najaf Governorate (near the Euphrates River) over two years (2024-2025).
The results of a field survey conducted from September 2024 to April 2025 indicated two peaks in the increase of the fig wax scale insect during October and March, with the highest infestation rates recorded in October. The results of the insect’s increase indicated the presence of two determining factors: the first (temperature and humidity). The number of eggs laid by a single female was counted in the fall season, at an average of 603 eggs, while in the spring season, it increased to 1,214 eggs.
A study was also conducted to detect parasites associated with the insect C. rusci. The molecular identification results of samples collected from field survey areas in Najaf Governorate/Al-Haidariya District were confirmed using Whole-Genome Shotgun (WGS) DNA barcoding technology based on the COI gene and molecular identification of some of the insect’s genetic markers (large ribosomal subunit, small ribosomal subunit, and COXI). The insect was confirmed as C. rusci. The insect was named Ceroplastes rusci isolate Najaf-1, with greater than 99% confirmation. Special accession numbers for these genes were assigned to the gene bank (PV762166, PV750210). The complete genome of C. rusci was determined for the first time in Iraq in this study, which is the first complete genome sequence of Ceroplastes rusci from the isolate named “Najaf-1”. The genome sequence has been deposited in GenBank under accession number JBPAZG000000000.1. The nucleotide sequences of the insect’s mitochondrial genes have been registered in GenBank, where the mitochondrial sequence of the fig wax insect collected in this study is 14,800 bp long and contains 10 protein-coding genes (PCGs) which include (Cox1), (Cox2), (Cox3), (Cob), (Nad1), (Nad2), (Nad3), (Nad4), (Nad5), (atp6), and there are two ribosomal RNAs: L rRNA and S rRNA. The mitochondrial genome of the studied Iraqi insect has been deposited in GenBank under accession number PV751233.
A symbiotic bacterium associated with the insect (Wolbachia endosymbiont) was discovered and registered in GenBank under serial number (PV755692.1). Four species of insect parasites associated with the wax scale insect were also recorded for the first time in Iraq: Scutellista cyanea isolate Najaf-1, Aphytis hispanicus isolate Najaf-1, Pachyneuron muscarum (Linnaeus), and Bothriophryne fuscicornis, which were registered in GenBank under accession number (PV754474).
To evaluate the effectiveness of integrated pest management (IPM) against the adult stage of the wax scale insect C. rusci L. in the laboratory and field (spraying, irrigation) during the fall season from October 1, 2024 to November 1, 2024, the effects of chemical pesticides (Conan, Actara), nanomaterials (zinc oxide nanoparticles), mineral oil, and biopesticides (Beauveria bassiana fungus, Bacillus thurngiensis bacteria) on fig trees were tested. Irrigation treatments were limited to the use of two systemic chemical pesticides (Actara, Conan). Experiments were repeated with the same control agents and methods for the spring season from February 15, 2025, to March 15, 2022. The experiments were designed using a CRD design in the laboratory and an RCBD design in the field. The results of laboratory experiments for the autumn season showed a clear, significant effect, most notably the effect of nano zinc at a concentration of 400 mg/l on the tenth day after treatment, where the mortality rate reached 100%. This was followed by the application of two chemical pesticides (Actara at a concentration of 0.30 g/l, Conan at a concentration of 0.75 g/l) on the same day, with mortality rates reaching 98.71% and 96.26%, respectively.
Meanwhile, mineral oil recorded a mortality rate of 93.3% on day 10 at a concentration of 4 ml/l. The lowest mortality rates were achieved by the biological pesticides, specifically the fungal biological agent, which reached a mortality rate of 87.8% on day 14 at a concentration of 6 g/l. This was followed by the bacterial biological agent, which reached 65.03% on the same day at a concentration of 1.5 g/l. Field experiments using the spraying method confirmed the laboratory results, but with relatively lower mortality rates.
The Actara treatment gave the highest mortality rate of 96.87% at a concentration of 0.30 g/l, while the bacterial pesticide was less effective with a mortality rate of 71.27% at a concentration of 1.5 g/l. In the field experiment using the irrigation method for chemical pesticides, the Actara pesticide was superior at a concentration of 0.25 g/l with a mortality rate of 91.17% on day 10, followed by the Conan pesticide at a concentration of 0.75 g/l with a mortality rate of 90.95%. The control results for the autumn and spring seasons showed a similar pattern to that recorded in the autumn season, but with relatively lower mortality rates.