Optimal Sterile-Insect and Pheromone Deployment for False Codling Moth Suppression: A Stability- and Sensitivity-Driven Model

Abstract

A nonlinear host–pest model was formulated to assess combined sterile insect technique and pheromone trapping against the false codling moth textit{Thaumatotibia leucotreta}. Next generation methods yielded the basic reproduction number $R_{0}$, which equalled 0.86 under baseline field estimates. Parameter sensitivity showed that a 15\% increase in the sterile mating rate $\lambda_{4}$ cut $R_{0}$ by 48\%. Centre manifold reduction uncovered a backward bifurcation at $R_{0}=1$; therefore, eradication requires both $R_{0}<1$ and releases large enough to surmount the fold. Pontryagin’s minimum principle supplied an optimal weekly schedule: $2\,000$ sterile males ha$^{-1}$ together with 25 pheromone traps ha$^{-1}$. This control mix lowered peak larval density by 38\% and accelerated host plant recovery, raising biomass by 12\% within 60 d relative to constant rate programmes. All biological parameters were sourced from peer reviewed laboratory and field studies; no proprietary data were used. The results endorse integrated deployment of sterile males and pheromone lures as a cost effective strategy for protecting high value perennial crops.