Chemical composition and acaricidal activity of essential oils from Alpinia zerumbet, Bixa orellana, Mesosphaerum suaveolens and Syzygium cumini against Oligonychus punicae on clonal seedlings of Eucalyptus grandis

Oligonychus (Oligonychus) punicae (Hirst) (Acari: Tetranychidae) is a phytophagous mite that causes significant damage to various crops, including Eucalyptus grandis , where infestations can lead to leaf discoloration, reduced photosynthetic capacity, and overall plant stress. Due to its economic importance, sustainable control strategies are needed. Essential oils (EOs) have emerged as promising tools for managing phytophagous mites, but their effects on O. punicae remain poorly studied. This work evaluated the acaricidal potential of EOs from Alpinia zerumbet , Bixa orellana , Mesosphaerum suaveolens , and Syzygium cumini . EOs were extracted by hydrodistillation and analyzed by GC-MS. Acaricidal activity was assessed through toxicity, ovicidal and repellent tests, and effects on population growth rate. The main constituents (>5 %) were mainly monoterpenoids and sesquiterpenes, with composition varying among species. Toxicity tests showed that at LC 50 , the oil of B. orellana exhibited the highest lethality (0.55 μL/mL). At LC 90 , both A. zerumbet and B. orellana were more toxic than S. cumini , with toxicity ratios (TR) of 9.1 and 5.6, respectively. All EOs reduced egg viability by over 50 %, with S. cumini reaching 79.25 % of non-hatched eggs. Population growth was still positive under EO exposure, but all treatments significantly reduced the intrinsic rate of increase compared to the control. All EOs also exhibited repellent activity at sublethal concentrations, with A. zerumbet showing the highest repellency. These results highlight the potential of EOs as effective acaricidal agents against O. punicae . While no single oil excelled in all parameters, each demonstrated specific strengths, supporting their complementary use, individually or in combination, in integrated pest management programs. • Essential oils from four plant species were chemically characterized. • Bixa orellana oil showed the highest toxicity to Oligonychus punicae. • Syzygium cumini oil reduced egg viability by nearly 80 %. • Population growth of O. punicae was significantly reduced by all oils. • Essential oils showed repellent activity, supporting IPM strategies.