"on the one hand Mexico is the main supplier of vegetables to the southern US, on the other hand Canada supplies tomatoes and pulses. Although many of these crops can be replaced or substituted by local produce, the 'disrupting' effect of established supply chains could lead to price spikes or shortages, as happened with avocados in January which became very expensive on US shelves. James Knightley, chief economist at ING, has estimated that the effect for a US family of four will be about $3,342 in one year considering all possible increases'