Neonicotinoid resistance of Aphis gossypii Glover, 1877 (Hemiptera: Aphididae) in cotton fields of Çukurova Region, Turkey

Abstract

Cotton aphid, Aphis gossypii Glover, 1877 (Hemiptera: Aphididae), is a major pest in cotton fields. Neonicotinoids are important and highly prevalent insecticides currently used against A. gossypii and other herbivorous insect pests in the Mediterranean Region of Turkey. However, some insecticide applications against A. gossypii in the Çukurova Region have failed despite using high rates. Therefore, bioassays and enzyme analyses were conducted to determine resistance to imidacloprid and thiamethoxam in A. gossypii populations collected in 2015-2016 from cotton fields in this region. Resistance factors (RF) were 54.6 to 206.5 fold for imidacloprid and 5.7 to 65.7 fold for thiamethoxam. Populations from Kürkçüler (RF 206.5) had the highest LD50 for imidacloprid and from Körkuyu (RF 65.7) for thiamethoxam. Enzyme analysis revealed statistically higher metabolic resistance. Maximum enzyme activities were 17.8, 142.3 and 3.8 nM/min/mg protein for carboxylesterase for in Körkuyu, for glutathione S-transferase in Bahçe and for cytochrome P450 monooxygenase in Körkuyu, respectively. This study revealed the development of resistance in A.gossypii to neonicotinoid insecticides in Turkey and the need for new management strategies to break this resistance.

Overexpression of cytochrome P450 genes in Aphis gossypii (Glover) in the cotton fields of the Çukurova region, Turkey

“…The weakest GST activity was found in the Akyuva population (1.05 U/ml) (Table 1). Likewise, it was reported that, 3.3 times more enzyme activity was found in the neonicotinoid-resistant A. gossypii populations in the province of Adana in 2016 (Ulusoy et al 2018). These results provide evidence that these populations have metabolic resistance still in this region.…”

“…5.9 times more AChE activity was observed in comparison to the reference population (Table 1). In parallel with these results, another study that was carried out in this region found 6.5 times more AChE activity in comparison to the reference population for A. gossypii populations (Ulusoy et al 2018, Velioglu et al 2008. As in the cases of AChE enzyme activity levels, the highest GST enzyme activities were found in the Çiftlikler population (2.68 U/ml) and Hamitbey population (2.33 U/ml).…”

“…Widespread and irresponsible usage of insecticides takes place in Çukurova, which is one of the most important regions involved in polyculture agriculture in the Mediterranean Region in Turkey. Neonicotinoid resistance was reported in A. gossypii in cotton fields in this region (Ulusoy et al 2018).…”

“…Cytochrome p450 activity was measured based on the method describe by Ulusoy et al (2018). 50 aphid individuals were homogenized in a Na -phosphate buffer (0.1 M pH: 7.5), the homogenate was centrifuged as 10 000 g at 4 ºC for 10 min, and the supernatant was used as an enzyme source.…”

“…Neonicotinoids are among insecticides with high market share that are effectively used in recent times for controlling especially aphids and whiteflies in the Coleoptera, Diptera and Lepidoptera families. However, varying ratios of development of resistance against this group of insecticides were reported in both the entire world and the Mediterranean Region due to its widespread and irresponsible usage (Jeschke et al 2011, Nauen et al 2008, Ulusoy et al 2018. Resistance mechanisms are caused by strengthened metabolic enzyme activities in organisms and reduction in the levels of sensitivity against xenobiotics as a result of mutations in target proteins (Nauen 2007).…”