The exposure risk of heavy metals to insect pests and their impact on pests occurrence and cross-tolerance to insecticides: A review

Changes in the Biology and Susceptibility of Weevil (Cylas formicarius) to the Insecticide Spinetoram as a Response to Cadmium Contamination

“…In China, the Cd point exceeding rates was 7.0% [13]; the risk screening value for Cd content in non-paddy field soils (PH ≤ 7.5) was 0.3 mg/kg, and it was 0.6 mg/kg for soils with a PH higher than 7.5 [14]. The Cd content in the soils ranged from 0.25 to 0.3 mg/kg in Guangdong province, which is close to the risk screening value [7].…”

“…Evaluation of the impacts of heavy metal exposure on herbivorous insects is particularly important for assessing eco-toxicological risk in food chains [ 46 ]. In addition, the development of insect heavy metal tolerance has probably led to the increase in their tolerance to pesticides [ 7 , 43 ], which may reduce the efficiency of pest chemical control and bring new challenges to pest control in the farmland with heavy metal pollution [ 46 ]. In this study, weevil resistance to spinetoram increased after exposure to a low level of Cd 2+ , but the sensitivity to B. bassiana was not affected by Cd contamination.…”

“…In this study, weevil resistance to spinetoram increased after exposure to a low level of Cd 2+ , but the sensitivity to B. bassiana was not affected by Cd contamination. Microbial control may be more suitable for pest control in heavy metal-polluted areas than chemical control [ 7 ]. Admittedly, the cross-tolerance was tested under controlled conditions, which enhances our understanding of the effects of single heavy metal on insects but may not accurately reflect the characteristics of natural communities because heavy metal pollution in the field generally involves a variety of heavy metals, and their impacts on insects are more diversified and complicated [ 46 , 56 , 57 ].…”

“…Heavy metal pollution is distributed globally because of human production activities, including mining, smelting, sewage discharge, and use of metal-containing pesticides and fertilizers [ 4 , 5 , 6 ]. It is estimated that the annual global emissions of Cd, Pb, and Cu reach approximately 1.0 × 10 6 tons, 5.0 × 10 6 tons, and 3.4 × 10 6 tons, respectively [ 7 ]. Cadmium can be easily taken up by agricultural crops due to the relatively good solubility of its salts in water, posing a threat to nearly all organisms [ 3 , 8 , 9 , 10 , 11 , 12 ].…”

“…Recently, the combined effects of heavy metals and other factors on insects have also received attention. Previous studies have shown that heavy metal exposure can induce tolerance (a phenomenon known as “cross-tolerance”) or affect susceptibility of organisms to other stressors [ 7 ]. Babczynska et al [ 2 ] reported that polypropylene fibers cause an increase in Cd accumulation in larval Spodoptera exigua .…”