Perspectives on California Berry Production: Labor Availability, Pest Management, and Trade Restrictions

Growers face myriad production constraints. Among them, labor availability, pest management decisions, and trade regulations play important roles in determining profitability. Invasions by exotic species interact with these production constraints in varied and unpredictable ways. The purpose of this dissertation is to utilize a recent invasion by an exotic vinegar fly, Drosophila suzukii Matsumura, the spotted wing drosophila (SWD), to investigate these constraints in California berry production. First detected in the US in 2008, SWD prefers to infest ripe soft-skinned fruit, the moment the fruit is commercially viable. Berry growers have responded to the SWD invasion by significantly altering the use of important inputs, especially labor and pesticides. Analysis of the interactions between the invasion and these input markets provides insights about the availability of seasonal labor in California agriculture, the manner through which unpredictable wage distortions contribute to the perception of agricultural labor shortages, and the economic factors motivating policies about pesticide residue limits.;The first essay tests the integration of California's agricultural labor markets with an emphasis on the market for seasonal berry pickers. Growers and media have reported labor shortages in recent years, particularly in industries reliant on seasonal harvesting labor. These observations are contrary to economic theory, which stipulates that labor shortages should only occur if arbitrage between regions is restricted or too costly. By comparing wages and employment in California at the state, region, and county-level using three market integration models, I find that California's agricultural labor markets are highly integrated, inconsistent with the possibility of a regional labor shortage.;The second essay proposes an alternative explanation for perceived labor shortages, an explanation specific to the effects of the new pest. The second essay models the effects of unpredictable fruit losses resulting from SWD infestations. These losses significantly affect yields and reduce worker productivity during harvest because workers perform the labor-intensive task of sorting infested fruit from marketable fruit. A majority of conventional raspberry production is harvested on a piece-rate basis, implying that SWD infestations distort worker earnings, all else equal. This essay includes simulations of the short- and long-run labor market effects associated with SWD's invasion in Central Coast raspberry production utilizing scientific data. Results indicate that SWD infestations cause significant distortions in workers' earnings that are difficult for managers to observe. These findings are consistent with the hypothesis that SWD contributes to the perception of labor shortages in raspberry production. More broadly, unpredictable wage distortions can cause managers to overestimate workers' earnings and thus set wages too low to attract the desired amount of labor.;The final essay explores the political economy of maximum residue limits (MRLs) for fresh strawberries. Strawberry growers, who have increased the frequency and concentration of their pesticide applications in response to SWD infestations, must adapt their pest management programs subject to the constraints imposed by these regulations. MRLs differ significantly by country despite the existence of an international set of MRL standards, the Codex Alimentarius, and are considered by many to be non-tariff trade barriers (NTBs). This essay uses regression analysis to identify the economic factors motivating MRL policy. Results indicate that wealthy countries with domestic strawberry production implement non-Codex strawberry MRLs. US strawberry MRLs regulating pesticides intensively used in domestic strawberry production are less strict than their corresponding Codex MRLs. These results indicate that strawberry MRLs are only partially motivated by science, supporting the theory that MRLs are effectively NTBs, at least in part. Developed countries that can afford the scientific studies required to justify non-standard MRLs set MRLs to maximize domestic welfare, as opposed to global welfare.