Toxicity of spinosad to susceptible and resistant strains of house flies,Musca domestica

Abstract

: The toxicity of spinosad, a new insecticide derived from the bacterium Saccharopolyspora spinosa, was evaluated against susceptible and resistant strains of house Ñy (Musca domestica L.). Spinosad was highly toxic to house Ñies based on 72-h values and the symptoms of poisoning were consistent with LD 50 a neurotoxic mechanism of action. Spinosad was relatively slow acting, with the maximum toxicity noted at 72 h. Piperonyl butoxide and S,S,S,-tributylphosphorotrithioate synergized the toxicity of spinosad by 3É0-and 1É8-fold, respectively, while diethyl maleate had no signiÐcant e †ect. These results suggest that there is a small degree of monooxygenase-mediated spinosad detoxiÐcation in house Ñies, while hydrolases may be only minimally important and glutathione transferases may have no role. There were no substantial levels of crossresistance detected, except in the LPR strain where a low 4É3-fold cross-resistance was observed. The cyclodiene-resistant OCR strain was 2É7-fold more sensitive to spinosad than the susceptible strain (CS). These results suggest that cross-resistance may not be a limiting factor for the use of spinosad against house Ñies.1998 Society of Chemical Industry ( Pestic. Sci., 54, 131È133 (1998)

Pyrethroid resistance and cross‐resistance in the German cockroach, Blattella germanica (L)

“…The resistance ratio of 1.3 for spinosad indicates that Apyr‐R is no more tolerant to spinosad than ACY. This result is similar to those of previous studies with resistant housefly strains that showed no cross‐resistance to spinosad 27. 28 Although a multi‐resistant housefly strain (LPR) has showed a 4.3‐fold cross‐resistance to spinosad,27 the very high level of resistance to pyrethroids observed in the LPR strain (RR = 16 000)29 suggests that 4.3‐fold cross‐resistance to spinosad is not a significant factor that would be likely to prevent the effective use of this new insecticide against insect pests.…”

“…Like imidacloprid, spinosad was relatively slow‐acting against German cockroaches, with maximum toxicity occurring at 72 h. This result agrees with a previous study 27. Compared with other insecticides tested in this study, spinosad had relatively low toxicity to German cockroaches, with an LD 50 value of 500 ng per cockroach (Table 1).…”

“…Compared with other insecticides tested in this study, spinosad had relatively low toxicity to German cockroaches, with an LD 50 value of 500 ng per cockroach (Table 1). This study indicates that the response of cockroaches to spinosad differs from that of house flies, where LD 50 values for spinosad ranged from 24 (72 h) to 94 (24 h) ng per fly 27. 28 Although Apyr‐R was highly resistant to pyrethroids and cross‐resistant to imidacloprid, there was no cross‐resistance to spinosad based on overlap of the 95% confidence interval between ACY and Apyr‐R (Table 1).…”

The spinosyn family of insecticides: realizing the potential of natural products research

“…18,101,102 This result reinforces the proposal for a unique MOA. However, as well known for other insecticides, continued usage is likely to exert selective pressures on insects and to eventually provoke resistance.…”

Unraveling the mystery of spinosad resistance in insects

“…1) is a new and highly promising insecticide, derived from the bacteria Saccharopolyspora spinosa, with efficacy against a wide range of insects. [1][2][3][4][5] The mechanism of action of spinosad appears to be unique, with a primary site of attack being the nicotinic acetylcholine receptor (nAChR) and a secondary site of attack being g-aminobutyric acid (GABA) receptors. [6][7][8][9][10][11] Spinosad is thought to exert its toxicity primarily by activating a nAChR (nAChN subtype).…”