Stage-specific predation and functional response of Orius insidiosus (Hemiptera: Anthocoridae) toward Diaphorina citri (Hemiptera: Psyllidae) and differential toxicity of formulated pesticide mixtures.

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the main vector of Huanglongbing (HLB), the most destructive disease affecting citrus production worldwide. Sustainable management of this pest requires the integration of biological and chemical control strategies. This study evaluated the predatory capacity, functional response, and insecticide selectivity of Orius insidiosus (Say) (Hemiptera: Anthocoridae) toward D. citri. Predation assays showed that O. insidiosus consumed all developmental stages of D. citri, with higher predation on eggs and nymphs. Functional response analysis revealed a Type II response, with high efficiency at low prey densities (attack rate = 3.62; handling time = 0.04), corresponding to a maximum consumption of approximately 25 prey per predator. Predation bioassay indicated significant differences in toxicity, with acetamiprid + bifenthrin, abamectin + cyantraniliprole, and alpha-cypermethrin + teflubenzuron causing >90% mortality, whereas glyphosate, azoxystrobin + difenoconazole, and chlorantraniliprole + abamectin showed lower toxicity (<50%). Concentration-response analyses indicated lower susceptibility of O. insidiosus compared to D. citri, with LC50 values ranging from 1.23 to 99.50 mg ml-1 for the predator and from 0.0016 to 1.187 mg ml-1 for the pest. All insecticides were classified as selective (SR > 1), although ecological risk varied. Probit substitution analysis indicated low predicted mortality (<90%). Overall, O. insidiosus is an efficient predator of D. citri, and further studies on its development and reproduction when preying on this pest are required. The tested pesticide mixtures showed selectivity, and further studies are needed to evaluate their efficacy at reduced application rates.