Resistance risk assessment to chlorpyrifos and cross-resistance to other insecticides in a field strain of Phenacoccus solenopsis Tinsley

Self Cite

BACKGROUND Cotton mealybug Phenacoccus solenopsis is a pest of cotton, vegetables, ornamentals, and medicinal plants. In many parts of the world P. solenopsis has been managed by integration of cultural, mechanical, biological and chemical methods, but in Pakistan the use of insecticide sprays has resulted in the development of resistance to some insecticides. In this study indoxacarb resistance was investigated by selecting a P. solenopsis population under laboratory conditions for many generations. The cross‐resistance potential of indoxacarb resistance with other chemistries and the realized heritability of indoxacarb resistance were also evaluated. RESULTS A field population of P. solenopsis selected with indoxacarb for 27 generations had a 25 623.17‐fold resistance level. The highly indoxacarb resistant population showed very high cross‐resistance to spinosad and very low cross‐resistance to bifenthrin and chlorpyrifos. The mean estimated h2 of resistance to indoxacarb was only 0.04. The number of generations predicted for the development of ten‐fold indoxacarb resistance at a constant h2 = 0.04 against selection intensities of 10% and 95% were 346 and 36 (slope = 3.18), 237 and 25 (slope = 2.18) and 128 and 13 (slope = 1.18). However, at a constant slope = 1.18 and selection intensities of 10% and 95%, the same increase in indoxacarb resistance occurred after 128 and 13 (h2 = 0.04), 103 and 11 (h2 = 0.05), and 86 and 9 (h2 = 0.06) generations. CONCLUSION This study revealed that P. solenopsis has a very high resistance to indoxacarb as a result of laboratory selection. Thus, resistance to this insecticide in the field may also occur. Indoxacarb resistance can be minimized by rotating it with bifenthrin and/or chlorpyrifos due to its very low cross‐resistance to these insecticides and by avoiding its rotation with Spinosad, which has very high cross‐resistance. © 2019 Society of Chemical Industry

Section: Discussioncontrasting

confidence: 99%

Laboratory selection, cross‐resistance, and estimations of realized heritability of indoxacarb resistance in Phenacoccus solenopsis (Homoptera: Pseudococcidae)

Afzal

Shad

Ejaz

et al. 2019

Self Cite

“…These results show that the expression level of alleles responsible for pymetrozine resistance varied over the range of selection pressures used. These results contrast with the findings of Tabashnik, 24 Lai and Su, 38 Abbas and Shad, 39 and Ijaz et al 35 and agree with the findings of Shah et al, 42 Abbas et al 43 and Ismail et al 36 In the present study, the h 2 observed after 18 generations of selection with pymetrozine (h 2 = 0.1360) was lower than that observed for L. striatellus after selection with pymetrozine (h 2 = 0.2070) 23 but higher than the values observed for B. tabaci after selection with thiamethoxam (h 2 = 0.1309) 44 and for B. tabaci to after selection with nitenpyram (h 2 = 0.1025). 45 These results suggest that B. tabaci strains are more likely to develop resistance to pymetrozine than to other insecticides.…”

Section: Discussionsupporting

confidence: 75%

“…Furthermore, if the probit line slope = 2.72 and the selection mortality = 90%, 11.4 generations would be needed to obtain a ten‐fold increase in the LC 50 , whereas 15.5 generations would be needed for the same to occur at a probit line slope of 3.72. In a field environment (as opposed to an indoor environment), the factors influencing resistance are more complicated; these factors include the migration of insects, uneven application and replacement of insecticides, and the complexity of the natural environment 36,38 . Therefore, the real risk of resistance in the field is lower, and the rate of development of resistance is substantially lower than the rate that occurs indoors.…”

Section: Discussionmentioning

confidence: 99%

“…The rate of development of resistance is related to the pest's biological characteristics as well as to the insecticide, the selection pressure, and the initial frequency of resistance. [35][36][37] In this study, the development of resistance in B. tabaci was relatively slow at the early stage, and this might be related to the low initial frequency of resistance in the population. The rapid increase in the rate of development of resistance at the later stage and the increase in the pymetrozine selection concentration might be related to the persisting pressure on B. tabaci.…”

Section: Discussionmentioning

confidence: 99%

“…In a field environment (as opposed to an indoor environment), the factors influencing resistance are more complicated; these factors include the migration of insects, uneven application and replacement of insecticides, and the complexity of the natural environment. 36,38 Therefore, the real risk of resistance in the field is lower, and the rate of development of resistance is substantially lower than the rate that occurs indoors. Nevertheless, the potential risks of pymetrozine should be considered.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Resistance of Bemisia tabaci Mediterranean (Q‐biotype) to pymetrozine: resistance risk assessment, cross‐resistance to six other insecticides and detoxification enzyme assay

Fan

Jin

Shuai

et al. 2021

BACKGROUND The whitefly Bemisia tabaci (Gennadius) is a severe pest that affects many field and glasshouse crops worldwide and has developed resistance to insecticides in most chemical classes. Pymetrozine, a neuroactive pyridine azomethine, is selective towards piercing‐sucking pests in Hemiptera. The aim of this study was to assess the resistance of B. tabaci Mediterranean (MED) to pymetrozine in the laboratory. RESULTS After successive selection of 18 generations of MED in the presence of using pymetrozine, there was an 11.28‐fold increase in the median lethal concentration (LC50). When the realized heritability (h2) of B. tabaci to pymetrozine in the field was assumed to be the value estimated in the laboratory (h2 = 0.1360) and the mortality was 70–90%, only 7.2–15.9 generations were estimated to be needed to obtain a ten‐fold increase in resistance to pymetrozine. Compared with the susceptible populations (G0), the Pyme‐SEL strain (G18) showed a low level of cross‐resistance to neonicotinoids (nitenpyram, imidacloprid, acetamiprid, and thiamethoxam) and no cross‐resistance to chlorpyrifos or abamectin. With the G0 and the Pyme‐SEL strains (G11 and G18) as test strains, the activity of multifunctional oxidase exhibited the greatest increase during selection, while the activities of carboxylesterase and glutathione‐S‐transferase did not change significantly. CONCLUSION This study show that a potential risk of development of resistance to pymetrozine exists in B. tabaci after continuous application. During the application of pymetrozine to control B. tabaci in the field, the frequency of its use in combination with neonicotinoids should be used with caution. © 2020 Society of Chemical Industry

Sulfoxaflor resistance in Oxycarenus hyalinipennis (Costa) induces negligible cross‐resistance to other tested insecticides: stability, risk assessment, and fitness cost

Wazir

Shad

2021

BACKGROUND: Oxycarenus hyalinipennis (Costa) (Hemiptera: Lygaeidae) is a polyphagous insect pest. In Pakistan, O. hyalinipennis is managed by using different insecticides, a major concern for cotton producers, and has developed resistance to many of these. Sulfoxaflor belongs to a newly released sulfoximine family that has high efficacy for controlling sap-feeding insect pests.RESULTS: A sulfoxaflor selected-population (Sulfo-Sel-Pop) of O. hyalinipennis showed a 3064.92-fold level of resistance after continuous selection for 18 generations with sulfoxaflor compared to unselected population (UNSel-Pop). The Sulfo-Sel-Pop showed a reduction in resistance (from 3064.92 to 635-fold) without exposure for five generations, indicating unstable resistance to sulfoxaflor. Cross-resistance studies of the Sulfo-Sel-Pop revealed no or very low cross-resistance to triazophos (0.42 to 0.30-fold), deltamethrin (0.85 to 0.18-fold) and acetamiprid (1.16 to 4.86-fold) from G 4 to G 19 compared to the field population (Field-Pop). The mean value of realized heritability was 0.15 in the Sulfo-Sel-Pop (G 19 ). Significantly reduced relative fitness was determined in the Sulfo-Sel-Pop (Rf = 0.21) followed by Crossand Cross 2 [(Sulfo-Sel-Pop ♀ × UNSel-Pop ♂) (Rf = 0.70)] compared with the UNSel-Pop. The values of intrinsic rate of natural increase (r m ), biotic potential (Bp) fecundity, egg hatching, and net reproductive rate (R0) were also significantly less in the Sulfo-Sel-Pop compared to UNSel-Pop. CONCLUSION: A very high fitness cost, unstable resistance and no or very low cross-resistance in the Sulfo-Sel-Pop have great implications in designing effective strategies for managing insecticide resistance to O. hyalinipennis.