Effect of Plant Essential Oil Formulations on Bemisia tabaci MEAM1 (Gennadius) and Its Parasitoid Eretmocerus hayati (Zolnerowich and Rose)

Abstract

Silverleaf whitefly (SLW), Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), consists of genetically diverse species known to cause significant destruction in many crops around the world. Nowadays, synthetic insecticides are a key component in the management of this pest. However, they also come with disadvantages, such as environmental pollution, pest resistance and recurrence, and toxicity to pollinators and natural enemies. Essential oils from aromatic plants and biocontrol agents may provide a new and safe alternative to synthetic chemicals. In this study, we assessed the lethal impact of three new plant essential oil formulations (referred to as F1, F2, and F3) against the developmental stages of B. tabaci and its parasitoid Eretmocerus hayati (Zolnerowich and Rose) (Hymenoptera: Aphelinidae). The tested formulations consisted of combinations of mustard oil and different surfactants. The formulations were effective against the eggs and nymphal stages of B. tabaci. At the highest concentration assessed (1.23%), F1 was the most effective formulation against the eggs, resulting in 85% mortality, whereas F2 was most effective against the nymphs (92.5% and 88.3% mortality for the young and old nymphs, respectively). However, adult mortality rates were below 40% for all the tested formulations. The range of median lethal concentration (LC50) values was between 0.65 and 1.05% for B. tabaci. The side effects of the three formulations were assessed against E. hayati, treated as parasitized nymphs of B. tabaci. At the highest tested concentration (1.23%), F2 and F3 resulted in 80% and 70% mortality of the parasitoids, respectively (classified as moderately or slightly harmful according to the IOBC), whereas F1 resulted in 17.5% mortality. As F1 was effective against SLW with minimal effects on the parasitoid, it is the most suitable formulation of those tested for use in an integrated pest management (IPM) program targeting the younger life stages of B. tabaci.

The Synergistic Effect of Lemongrass Essential Oil and Flometoquin, Flonicamid, and Sulfoxaflor on Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae): Insights into Toxicity, Biochemical Impact, and Molecular Docking

“…For example, ref. [11] shed light on the potent effects of three distinct mustard EOs which demonstrated LC50 values of 0.73%, 1.02%, and 1.05% (equivalent to 7300, 10,020, and 10,050 mg/L) on B. tabaci eggs, indicating their potential as a management agent against B. tabaci. The same oils showed efficacy, with LC50 values of 0.69%, 0.65%, and 0.88% (equivalent to 6900, 6500, and 8800 mg/L) on young nymphs and 1.03%, 0.91%, and 0.90% (equivalent to 10,300, 9100, and 9000 mg/L) on old nymphs, respectively.…”

“…This categorization provides clarity regarding the variety of chemical insecticides commonly employed in the management of B. tabaci [6]. However, long-term use of these insecticides has been reported to trigger B. tabaci to acquire resistance to these chemicals, providing challenges in its prevention and management [7][8][9][10][11].…”

“…The insecticidal properties of lemongrass EO to black cutworm Agrotis ipsilon, cotton leafworm Spodoptera littoralis, velvet caterpillar Anticarsia gemmatalis, greater wax moth Galleria mellonella, and cowpea weevil Callosobruchus maculatus have been demonstrated [22]. Despite the promising results of various plant essential oils (EOs) against B. tabaci [11], the use of commercial biopesticides based on EOs is still limited, indicating a potential for their incorporation into contemporary agricultural practices [23].…”