Bioeconomic Modeling and Welfare Impact of Biological Control of Papaya Mealybug Using Acerophagus papayae in Uganda: A Quasi-Experimental Approach

Biological control of papaya mealybug using Acerophagus papayae offers a plausible route to improved farm returns in Uganda, but ecological establishment alone does not establish a household welfare effect. This article synthesises published and institutional evidence and develops a bioeconomic and quasi-experimental analysis protocol. A purposive review of 24 sources links East African field studies, Ugandan programme documentation, host–parasitoid theory and modern difference-in-differences methods. Ugandan surveillance reports parasitoid occurrence outside release sites, making spatial interference a central identification concern. Kenyan research supports biological efficacy and reports favourable economic comparisons, while Indian valuation demonstrates the potential scale of benefits under country-specific assumptions. These findings cannot be treated as Uganda impact estimates. The proposed evaluation links dated release records, repeated biological monitoring, farm accounts and household outcomes. It distinguishes the effect of a release-and-extension programme from the effect of confirmed parasitoid establishment, uses cohort-specific comparisons where valid untreated observations remain, and explicitly evaluates contamination and differential trends. A proposed ecological module connects pest pressure to marketable yield, farm margins and discounted programme returns. A transparent hypothetical budget demonstrates how yield recovery, prices and programme costs determine benefit; it is not calibrated to Ugandan farms. The review identifies an evidential gap between documented establishment and causally identified welfare change. It recommends georeferenced surveillance, recoverable pre-intervention records, consistent monetary accounting and an explicit decision to withhold causal claims when suitable comparisons cannot be established. No new household treatment effect, fitted ecological parameter or national benefit estimate is reported.