This project looks for the relationship among variables influencing Mexican key lime supply and demand in the domestic and US market under the scenario of using a higher quantity of fertilizers as a strategy for responding against the threat of citrus greening (HLB). With the help of domestic and international databases from 2000 to 2012, a simultaneous equations model was built capturing behavioral and technical variables influencing supply and demand. The most important relationships among variables were price of the product and disposable income for the demand and use of fertilizers and exchange rate for the supply. This work gives the insight, from the economic point of view, that building a model including the right key variables will give a sense of the general structure of a market and the changes in stability due to a sanitary threat