TY  - JOUR
JF  - Acarologia
T1  - Acaricide resistance in the african red mite, Eutetranychus africanus (Tucker), infesting tangerine in Thailand
VL  - 66
IS  - Suppl
SP  - 197
EP  - 197
PY  - 2026
SN  - 0044-586X
SN  - 2107-7207
PB  - Les Amis d'Acarologia
AU  - Naphacharakorn, Ta-Phaisach
AU  - Ploychompoo, Konvipasruang
AU  - Wimolwan, Chotwong
AU  - Athitiya, Kaewpradit
AU  - Weerachai, Somsri
AU  - Apisit, Champukdee
UR  - https://doi.org/10.24349/mmcb-bmf9
DO  - 10.24349/mmcb-bmf9
DA  - 2026-07-20
ET  - 2026-07-20
KW  - Acaricide resistance
KW  - Tangerine pest
KW  - Citrus
KW  - Bioassay
KW  - Resistance management
KW  - Amblyseius swirskii
KW  - Phytoseiidae
AB  - The African red mite (Eutetranychus africanus Tucker) is one of the most damaging pest mites of citrus in Thailand, frequently causing leaf discoloration, reduced vigor, and yield loss. Continuous and repeated use of acaricides such as pyridaben, propargite, and amitraz has raised concerns about resistance development in field populations. This study aimed to evaluate the resistance levels of E. africanus populations collected from major tangerine-growing areas in Thailand and to provide evidence-based recommendations for acaricide resistance management. E. africanus collected from the different locations were reared to the F2 generation and tested for resistance using the leaf dipping technique. The experiments were conducted at the Laboratory of Mite and Spider Research Group, Department of Agriculture. Leaves of Erythrina fusca Lour were dipped into different concentrations of each acaricide, and 20 adult female mites were transferred onto each treated leaf per replicate. Each concentration was tested with at least six replicates. Mortality was recorded 72 hours after treatment. LC50 values were estimated using probit analysis, and resistance factors (RF) were determined by dividing the LC50 of each field population by the lowest LC50 recorded across all populations. E. africanus populations of from Chiang Mai, Kamphaeng Phet, Chumphon, and Bangkok exhibited different levels of resistance to the tested acaricides. RF values ranged from 1.00- 589.55-fold for pyridaben, 1.00-101.93- fold for propargite, and 1.00- 4.72-fold for amitraz. The E. africanus from Khlong Khlung District, Kamphaeng Phet Province, exhibited a very high resistance level to pyridaben (RF = 589.55 fold), while the population from Fang District, Chiang Mai Province, showed high resistance to pyridaben (RF = 55.22 fold) and very high resistance to propargite (RF = 101.93 fold). All E. africanus populations exhibited low resistance levels to amitraz. Therefore, to effectively manage E. africanus populations in citrus and delay the development of resistance, acaricides with high resistance levels in specific areas should be avoided, and acaricide rotation programs should be implemented.
ER -