المسح الميداني والتشخيص المظهري والجزيئي لبق القطن الدقيقي Phenacoccus solenopsis Tinsley , 1898 بأستخدام تقنية تسلسل الجيل التالي NGS التي تصيب نباتات الزينة في محافظة كربلاء المقدسة

Field survey and morphological and molecular identfiaction of cot-ton mealybug Phenacoccus solenopsis Tinsley, 1898 using next gen-eration sequencing (NGS), infecting ornamental plants in the holy Karbala province

Abstract

A field study was conducted on the presence of the cotton mealy-bug Phenacoccus solenopsis by conducting a field survey in nurseries and gardens in several areas of the holy Karbala Governorate (Al-Hussainiya Shrine Nurseries, Muhammad Al-Amin Street, College of Agriculture / University of Kerbala, Al-Hur Al-Sagheer area, Al-Intifada area) during the fall and spring seasons (2023-2024). The morphological and molecular identification of the insects was collect-ed from field survey areas in the holy Karbala Governorate.
The results of the morphological and molecular diagnosis showed that the diagnosed insect is the cotton mealybug Ph. solenopsis,and the nucleotide sequences of the insect’s mitochondrial genes were rec-orded in the GenBank under the serial numbers (PP768170 and PP768171) and four species of symbiotic bacteria associated with the insect were confirmed, namely (Candidatus Syntrophocurvum al-kaliphilum, Enterobacteriaceae endosymbiont, Buchnera aphidicola, and Candidatus Tremblaya endosymbiont) and were recorded in the GenBank under the serial numbers PP897797, PP897798, PP897799, and PP882706 respectively.
Three species of parasitoid wasp associated with the cotton mealy-bug were recorded for the first time in Iraq: Aenasius arizonensis, Mariettapictus,Cheiloneurus nankingensis.
The efficiency of all treatments used in the integrated pest control program in reducing the infection rate on ornamental plants was stud-ied in the laboratory and field. In the laboratory study, the chemical pesticides Actara and Conan outperformed all treatments in the la-boratory experiment with a mortality rate of 100% for adults and nymphs. The effect of nano-silica and mineral oil on the pathogenic fungi Metarhiziumanisopliaeand Beauveria bassiana was also studied in the laboratory. The results showed an insignificant effect when treating the pathogenic fungi with mineral oil and nano-silica, as the growth rate of the fungi M.anisopliaeand B. bassiana when interacted with nano-silica was 32.3 and 21.6, respectively, while the growth rate of the fungi M. anisopliaeand B. bassiana was 48 and 39.6 re-spectively in the comparison treatment. The effect of mineral oil was an inhibitor of the growth of M. anisopliae and B. bassiana by 22.6 and 32, respectively, while the growth rate of the two fungi in the comparison treatment was 48 and 39.6, respectively.
The effect of the interaction of mineral oil and nano-silica on the adults and nymphs of the cotton mealybug was studied, and the re-sults showed significant differences in the death of adults and nymphs of the cotton mealybug according to the different periods. The effect was greater on adults thanon nymphs, as the average death rate for adults was 33.3%, and the average death rate for nymphs was 12.3%. In field studies, both chemical pesticides, Actara and Conan, outper-formed the rest of the treatments. Conan was the most effective pesti-cide, with a rate of 83.7% on adults and 78.0% on nymphs, while the pathogenic fungi (M. anisopliae and B. bassiana) had an effect rate of 51.8 and 47.6% on adults, respectively, at a concentration of 6 g/L for each. As for nymphs, the effect rate of the pathogenic fungus M. an-isopliae was 40.9% at a concentration of 6 g/L and B. bassiana at a rate of 35.6% at a concentration of 5 g/L.
The pathogenic fungus M. anisopliae was the most effective for both adults and nymphs of cotton mealybugs. The efficiency of the interaction of nano-silica and mineral oil with the chemical pesticide Conan was also studied in the field. The interaction treatment between mineral oil and the chemical pesticide Conan was superior for both nymphs and adults of the cotton mealybug, as it gave the highest mor-tality rate at a concentration of 0.20 ml/liter Conan and 300 mg/liter mineral oil. The average efficiency rate of the interaction treatment reached 86.6% for adults and 81.8% for adults.