Sublethal Effects of Imidacloprid on the Population Development of Western Flower Thrips Frankliniella occidentalis (Thysanoptera: Thripidae)

Abstract

The Western flower thrips (WFT, Frankliniella occidentalis) is a global polyphagous pest that is often dependent on chemical control. Imidacloprid has been a commonly used chemical insecticide for effective control of WFT. Low concentrations of insecticides can have sublethal effects on individual insects. However, no more information is known about the effects of exposure at low concentrations of imidacloprid on WFT. Here, we evaluated the effects of imidacloprid at sublethal concentrations on WFT population growth parameters. We first exposed the parental generation to LC10 (56.8 mg/L) and LC25 (79.2 mg/L) concentrations of imidacloprid. We then quantified various parameters related to the development, survival, and fecundity of the F1 generation also exposed to these same concentrations. The development time of the treatment groups exposed to imidacloprid was significantly shorter than the control group, and the net reproductive rate (R0) was significantly higher for treatment groups than for the control group. For both variables, there was no significant difference between LC10 and LC25 exposure. The generational survival rate was significantly higher for the control group, followed by the LC10 treatment group and then the LC25 treatment group. However, the opposite was true for fecundity and intrinsic rate of increase (rm) of WFT. In summary, exposure to low concentrations of imidacloprid was positive for the population development of WFT, which may contribute to the development of insecticide resistance and cause resurgence in WFT populations.

Advances in Controlled-Release Pesticide Formulations with Improved Efficacy and Targetability

“…Agathokleous et al believe that a broader perspective should be considered to evaluate the safety of nanoformulations, including possible positive impacts on biodiversity. For example, pesticides may have positive effects on the population development and demographic fitness of agricultural insect at low concentrations/doses. − And may alter reproduction and the diversity of insect populations . Carbon nanomaterials have been shown to increase the diversity of soil microarthropods including total taxonomic richness, Shannon diversity index, and community dominance index, and decrease the evenness index .…”

Biological and Histological Alterations in The Larvae of Culex pipiens L. (Diptera: Culicidae) Induced by Imidcaloproid and Tannic Acid

“…Where cyclic neonicotinoids are more lipophilic than the other open-chain compounds so, IMI can reach the nervous system faster which explains the efficiency of IMI and the high mortality rates over tannic acid. In addition to the high percentage mortality of IMI, it also slightly decreased the pupation period but did not affect the total developmental rate as reported in Cao et al (2019).…”

Sublethal Effects of Imidacloprid on Fecundity, Apoptosis and Virus Transmission in the Small Brown Planthopper Laodelphax striatellus

“…This phenomenon has been found in several sucking insects when exposed to sublethal concentrations of imidacloprid, such as M. persicae [27,54], A. glycines [26], and Podisus maculiventris [55]. In Frankliniella occidentalis [15], Cyrtorhinus lividipennis [28,56], and Tryporyza incertulas [57], the fecundity was also stimulated by the lower concentrations of imidacloprid. Additionally, sulfoxaflor [58], triazophos and validamycin [11] could also enhance the fecundity of SBPH with low sublethal concentrations.…”

“…In the field, insecticides degrade over time or via wind, photolysis and hydrolysis, the concentration of insecticides initially used to control insects decrease until they reach the sublethal levels, resulting in sublethal effects on insects [12,13]. The biological performances and physiological processes of insects would be modified when exposed to sublethal doses of insecticides [14,15].…”