Wheat:  Net sales of 122,100 metric tons for delivery in the 2018/2019--a marketing-year low--were down 71 percent from the previous week and 72 percent from the prior 4-week average.   Corn:   Net sales of 586,500 MT for 2018/2019 were down 25 percent from the previous week and 17 percent from the prior 4-week average.    Soybeans:   Net sales of 313,400 MT for 2018/2019 were down 47 percent from the previous week and 61 percent from the prior 4-week average.    Soybean Cake and Meal:    Net sales of 79,200 MT for 2018/2019 were down 76 percent from the previous week and 67 percent from the prior 4-week average.   Soybean Oil:    Net sales of...