Effects of Pest Damage and Grain Management Practices on Storage Behavior and Market Prices: Insights from Benin

Didier K Kadjo, Purdue University


This thesis investigates the effects of storage losses, especially insect damage, on storage behavior and market prices. Although we treat these research questions in two separated essays, they are both embedded in the farmers' decision of grain storage. Farmers store grain either for consumption, sale or both. We address the research questions with cross -sectional data from a survey of 360 rural households in Benin. In the essay 1, we use an econometric model of storage to analyze how a household with access to storage technologies makes his or her storage decision in the presence of high insect damage and price variability. We find that storage technologies may have differential effects on a household's storage decision. Chemical use, for instance, has a marginal statistically significant effect on storage, suggesting that on average farmers using chemicals store 193 kg more than other farmers who do not use chemicals. In contrast, the use of plastic (mostly woven polypropylene) bags reduces the stored quantity by 296 kg, because this technology also facilitates the harvest period sales. The results also suggest that market-driven farmers may rely on high post-harvest prices as a shield against expected losses from storage. But subsistence farmers remain vulnerable to storage losses, and financial constraints during the harvest period might even weaken their food security during the post-harvest period. In the essay 2, we compare hedonic price models and contingent valuation methods to estimate the price premium for grain damaged by insects (Larger Grain Borer). Following the hedonic model, we find that a price discount is applied to low grain quality, because farmers' past market transactions reveal that 1% increase in grain damage results in a price discount of 0.32 %. Farmers are knowledgeable of this price premium for grain quality and their preferences obtained from the contingent valuation suggest a higher discount price, approximately 0.90 % for 1% increase in grain damage. The estimates of price discount are almost consistent for both sale and consumption transactions in either estimation approach. The difference being that in the hedonic model, consumption price discount is statistically significant for high levels of insect damage (50%) for maize purchases, while sale price discount is statically significant starting for lower level (30%). This result implies that farmers place less value on the quality of grain consumed when they run out of inventory. This thesis highlights that improved storage methods need to be developed and promoted because they are valuable to both income and food security in the post-harvest period. Without effective storage technologies, the vulnerability of groups such as households headed by women and subsistence farmers increase in the presence of insect damage. In addition, the use of uncertified chemicals and farmers' low level of interest for grain quality in periods of food scarcity raise concerns about health risk.




Ricker-Gilbert, Purdue University.

Subject Area

Agricultural economics

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