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The broad mite, Polyphagotarsonemus latus (Banks), is an important phytophagous mite that causes extensive damage to a wide range of crop species across the world. Fenazaquin, a mitochondrial electron transport inhibitor (METI), is one of the commonly used acaricides for the management of P. latus. The response to fenazaquin selection over generations and the risk of development of resistance was estimated herein using a laboratory‐selected population of P. latus (FEN‐SEL). Repeated exposure to fenazaquin over generations resulted in decreased susceptibility (99.32 folds) as compared to the unselected counterpart. FEN‐SEL took 26 generations for a 10‐fold increase in resistance with a realized heritability (h2) of 0.12 which indicated a low genetic variation and high phenotypic variation. Over a selection intensity of 20%–80% mortality, the generations required for a 10‐fold increase in LC50 for fenazaquin were 14.21–55.75, 7.75–30.41 and 5.33–20.91 at h2 values of 0.12, 0.22 and 0.32, respectively, with a constant slope of 2.39. The FEN‐SEL population also exhibited moderate levels of cross‐resistance to diafenthiuron, dicofol and spiromesifen and low cross‐resistance to propargite. The findings suggest a rational and rotational application of fenazaquin in the field to delay the development of resistance and to prolong its efficacy against P. latus. [ABSTRACT FROM AUTHOR]

The broad mite, Polyphagotarsonemus latus (Banks), is a cosmopolitan pest that attacks a wide range of economically important crops like hot and sweet peppers, mulberry, jute, tea and several ornamentals. This study was undertaken to monitor the development of acaricide resistance, if any, in five representative field-collected populations of Karnataka, India. Bioassays were carried out against five acaricide chemistries, and resistance ratios were calculated by comparing the LC50 values of field populations with the susceptible laboratory population (Pa-Lab). The resistance ratios varied from 26.03 to 81.16-fold for diafenthiuron, 27.35 to 83.47-fold for dicofol, 9.72 to 45.42-fold for fenazaquin, 8.77 to 16.84-fold for propargite and 48.37 to 163.39-fold for spiromesifen. Resistance to the acaricides was unstable in P. latus as a decline in resistance (14.11-102.53-fold) was observed over generations in the absence of selection pressure. The results suggest that acaricides should be sprayed at economic threshold levels or on a rotation basis for one or more seasons for better management of P. latus by delaying the development of resistance. [ABSTRACT FROM AUTHOR]