Wheat:  Net sales of 312,100 metric tons for 2019/2020 were down 53 percent from the previous week and 43 percent from the prior 4-week average.  Corn:  Net sales reductions of 165,900 MT for 2018/2019--a marketing-year low--resulting in increases for Mexico (44,800 MT, including 30,000 MT switched from unknown destinations and decreases of 38,700 MT), Taiwan (8,900 MT), Colombia (7,200 MT, including 7,500 MT switched from unknown destinations and decreases of 1,000 MT), Barbados (2,100 MT, including decreases of 200 MT), and Canada (1,200 MT, including decreases of 500 MT), were more than offset by reductions for China (157,500 MT), unknown destinations (59,500 MT), and Japan (12,400 MT).  For 2019/2020, net sales of 4...