Lethal and Sublethal Effects of Chlorpyrifos on Biological Traits and Feeding of the Aphidophagous Predator Harmonia axyridis

Abstract

Except of pest control, insecticides have shown adverse effects on natural enemies as well. Thus, risk assessment of pesticides for biological control agents is critical for effective use in integrated pest management (IPM) schemes. In the present study, the lethal and sublethal effects of chlorpyrifos, a commonly used insecticide that may negatively affect biological control agents, were evaluated on a non-target predator, the Asian ladybeetle Harmonia axyridis. Previous studies have reported on lethal concentrations, but the effects of sublethal concentrations remain unclear. Lethal and sublethal concentrations of chlorpyrifos were applied to third instar larvae of H. axyridis, and different growth and developmental parameters were measured. Treatment with LC10 (4.62 mg a.i. L−1) significantly shortened the developmental period of third instar larvae, whereas it significantly prolonged those of fourth instar larvae and pupa. Treatment with LC30 (9.59 mg a.i. L−1) significantly increased the larval and pupal developmental period compared with that of the control, whereas feeding potential, female fecundity, and adult longevity significantly decreased after LC10 and LC30 treatment. The pre-oviposition period significantly increased compared with that of the control. Population growth parameters, the finite (λ) and intrinsic rate of increase (r) and the net reproductive rate (R0), decreased following exposure to sublethal concentrations of chlorpyrifos. According to the results, the use of chlorpyrifos in IPM schemes requires further research because even sublethal concentrations of this insecticide were harmful to H. axyridis population growth.

Functional response of Harmonia axyridis preying on Acyrthosiphon pisum nymphs: the effect of temperature

“…Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is a generalist predator, is geographically wide-spread 37 , and has been extensively employed as a biocontrol agent of soft-bodied insects, including aphids in a diversity of crops 38 . Various biological aspects of H. axyridis relevant to its predatory potential (e.g., phenological characteristics, life table parameters, and generally Type II functional response), have been investigated with respect to temperature and other factors 39 , 40 . Although functional responses have been measured for H. axyridis on many crop pests 41 , 42 , information on the predation and functional response of H. axyridis to A. pisum is limited 43 .…”

Effect of Ingestion Exposure of Selected Insecticides on Coccinella septempunctata and Harmonia axyridis (Coleoptera: Coccinellidae)

“…However, at the same time they may have negative impacts on non-target beneficial organisms, important as natural enemies [ 40 , 45 ]. Both acute and sublethal effects have often been studied on different organisms, including ladybirds [ 36 , 37 , 38 , 42 , 45 , 48 ].…”

“…The direct impact of pesticides on H. axyridis has been widely studied under field and laboratory conditions, and for application to different agricultural systems [ 18 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ], showing that the species’ susceptibility to different pesticides is variable and depending on the developmental stage. Some studies show that adults are more often less susceptible than are immature instars [ 18 , 38 ]. Coccinellids may be also exposed to insecticides indirectly, by consuming the insecticide-treated prey [ 39 , 40 ].…”

Temperature-Dependent Functional Response of Harmonia Axyridis Pallas (Coleoptera: Coccinellidae) Preying on Acyrthosiphon Pisum (Harris) (Hemiptera: Aphididae) Nymphs

“…However, the change of functional response type with respect to prey distribution 74 or prey quality (either pesticide treated or untreated) have been shown for Harmonia axyridis 48,49 , suggesting complex nature of predatorprey interactions, and, emphasizing the need for further assessments of current ndings with regard to general factors like pesticides 75 . Insecticides from synthetics and biopesticides groups are commonly applied worldwide [76][77][78] and shown to have profound effects, both positive or negative, on behavioral or physiological responses of predators 45,79 .…”

“…Various biological aspects of H. axyridis of importance for its predatory potential (e.g. phenological characteristics, life table parameters, and functional response (generally with a Type II response), have been investigated with respect to the temperature and other concerning factors [45][46][47][48][49] to many crop pests [50][51][52] , however, information on its predatory behavior and functional response to A.…”