**Acknowledgements**

Selectivity is an important factor in managing resistance in pest insects [27]. Many studies with basic lines of susceptibility have been done with chlorantraniliprole insecticide and Lepidop‐ tera, and the observations are that populations show susceptibility with low variation in mortality [28,29]. The insecticide abamectin is not considered old and has been effective in controlling this pest insect, with no flaws detected in its control of *L. coffeella* as of yet. Despite the abamectin insecticide not being among those at risk of resistance in *L. coffeella*, this insecticide has not been studied. However, many arthropod pests have been classified as being at risk for resistance to this group. Among them are *Leptinotarsa decemlineata* (Say) [30], *Musca domestica* [31], *P. xylostella* [32], *Frankliniella occidentalis* [33], and *Tetranychus urticae* [34]. Abamectin resistance has been observed in populations of *F. occidentalis* [35] and *Liriomyza trifolii* [36]. Deltamethrin had surprising results, with low discrepancy between the resistant and the susceptible populations (5 times) compared to their insecticides such as thiamethoxam (10 times) that are less used in coffee plantation. In recent years, however, the number of pyrethroid applications in coffee production has been greatly reduced. Despite the low resistance to pyrethroids, however, the variation has been observed in Brazil for the moth *P. xylostella* [37] as well as with other pyrethroids (cypermethrin, β-cypermethrin, deltamethrin, and esfenvalerate) in Pakistan, India, China, and Korea [38,39]. Although deltamethrin has affected fewer Brazilian populations of *L. coffeella*, a difference of 5 times is cause for concern

Insects usually have a resistance mechanism that confers nerve insensitivity, known as knockdown resistance (Kdr), as first reported in *M. domestica* (L.) (Diptera: Muscidae) [40]. This type of resistance is found in other agricultural pests based on patterns of cross-resistance and the absence of compound synergism that inhibits the activity of cytochrome P450 and esterase

The insecticide thiamethoxam has been frequently used and can be applied as a spray or via the soil [42]. There are no studies of lepidopteran resistance to this insecticide. Control failures were observed depending on the time of application, however, for example [43] observed

The grouping of populations from Rio Paranaíba, Carmo do Paranaíba, and Abaeté (Group I) and Santa Teresa with Guaraciaba (Group II), coupled with the significant response of the effect of distance on the LT50 of the chlorpyrifos, profenofos, and deltamethrin insecticides, showed that resistance was affected by the collection distance of these populations since more

Studies have shown a strong relationship between collection distance and resistance patterns [44,10,45,12]. All of these studies showed significant association of resistance with distance, and nearby populations tended to show more similar responses, as is the case for *P. xylostel‐ la* (L.) (Lepidoptera: Plutellidae). Chen et al. [46] studied the resistance of pyrethroids to *Culex pipiens* (Diptera: Culicidae) and found different frequencies of resistance at different locations, ranging from 21.4% to 79.8%. Moreover, this type of response may be associated with the large

Adults of *L. coffeella* disperse easily between coffee crops and have different densities in different environments [47-49]. Moreover, there is a geographic corridor between the largest-

since it should have been more effective.

effectiveness of 4.1%, 50.6%, 62.1%, and 69.0%.

closely connected populations had similar resistance responses.

dispersal capacity of adult *L. coffeella* and the sampling characteristics.

enzymes [41].

12 Insecticides Resistance

The funding and fellowships provided by the following Brazilian agencies were greatly appreciated: CAPES Foundation from the Brazilian Ministry of Education, National Council for Scientific and Tecnological Development (CNPq), and Minas Gerais State Foundation for Research Aid (FAPEMIG).
