Evaluation of Resistance Development in Bemisia tabaci Genn. (Homoptera: Aleyrodidae) in Cotton against Different Insecticides.

Muhammad Zaryab Khalid,Ibrahim Al-Ashkar,Guohua Zhong,Liyun Liu,Ayman EL Sabagh,Sohail Ahmed

doi:10.3390/insects12110996

Abstract

Cotton is a major crop of Pakistan, and Bemisia tabaci (Homoptera: Aleyrodidae) is a major pest of cotton. Due to the unwise and indiscriminate use of insecticides, resistance develops more readily in the whitefly. The present study was conducted to evaluate the resistance development in the whitefly against the different insecticides that are still in use. For this purpose, the whitefly population was selected with five concentrations of each insecticide, for five generations. At G1, compared with the laboratory susceptible population, a very low level of resistance was observed against bifenthrin, cypermethrin, acetamiprid, imidacloprid, thiamethoxam, nitenpyram, chlorfenapyr, and buprofezin with a resistance ratio of 3-fold, 2-fold, 1-fold, 4-fold, 3-fold, 3-fold, 3-fold, and 3-fold, respectively. However, the selection for five generations increased the resistance to a very high level against buprofezin (127-fold), and to a high level against imidacloprid (86-fold) compared with the laboratory susceptible population. While, a moderate level of resistance was observed against cypermethrin (34-fold), thiamethoxam (34-fold), nitenpyram (30-fold), chlorfenapyr (29-fold), and acetamiprid (21-fold). On the other hand, the resistance was low against bifenthrin (18-fold) after selection for five generations. A very low level of resistance against the field population of B. tabaci, at G1, showed that these insecticides are still effective, and thus can be used under the field conditions for the management of B. tabaci. However, the proper rotation of insecticides among different groups can help to reduce the development of resistance against insecticides.

Highlights

Cotton is a major cash crop, and Pakistan is the fourth largest cotton producer in the world
For the Lab-PK population, toxicities of acetamiprid, imidacloprid, thiamethoxam, nitenpyram, chlorfenapyr, and buprofezin were notably higher as compared to bifenthrin and cypermethrin (Table 2)
The results of the present study showed that the selected insecticides are effective against the field-collected whitefly population [17], and can be used under the field conditions for the management of B. tabaci

Summary

Introduction

Cotton is a major cash crop, and Pakistan is the fourth largest cotton producer in the world. The vertical tap root system makes the cotton tolerant to high temperatures and drought [1]. B. tabaci is a major pest of cotton that damages by direct feeding, reduces seed quality through the excretion of honeydew, subsequently develops sooty mold [2], and transmits leaf curl virus [3]. B. tabaci was ranked 5th among the world’s top 12 most insecticide-resistant insect species [4]. Resistance develops readily in insect pests due to the unwise and indiscriminate use of insecticides [5,6]. The development of resistance against insecticides is a global concern. An improved understanding of resistance could be a helpful tool for preparing insect management strategies. A laboratory selection with insecticides is one of the distinct methods used to determine the risk of insecticide resistance development

Methods

Results

Discussion

Conclusion