KANSAS CITY, Mo. — Modest but continuing deterioration in the corn and soybean crops was reported in the latest Crop Progress data from the US Department of Agriculture for the week ended July 29. Spring wheat crop conditions improved slightly during the period, the USDA said.

Drought conditions continued without significant improvement in much of the Midwest in the latest week. Weather conditions in spring wheat areas were somewhat milder, allowing for slight improvement where the crop was not yet fully mature. The harvest continued to make progress well ahead of average.

In the 18 major corn-growing states, only 24 percent of the corn crop was rated good to excellent, down from 26 percent the previous week, the USDA said. A total of 48 percent of the crop was in very poor to poor condition as of July 29, up from 45 percent a week earlier. A year ago in the same week, 62 percent of the crop was rated good to excellent and only 14 percent was very poor to poor.

As of July 29, a total of 29 percent of the soybean crop was rated good to excellent in the 18 major soybean-growing states, down from 31 percent the previous week, the USDA said. A total of 37 percent of the crop was in very poor to poor condition during the latest week, up from 35 percent very poor to poor in the previous week. In the same week a year ago, 60 percent of the soybean crop was rated good to excellent and only 12 percent was very poor to poor.

In contrast to corn and soybeans, the condition of the spring wheat crop remained strong. The USDA said 63 percent was in good to excellent condition in the six major spring wheat states, up from 60 percent in the previous week but below 70 percent in the same period a year ago. A total of 11 percent of the crop was in very poor to poor condition as of July 29, the same as in the previous week and up from 7 percent the same week a year ago, the USDA said.

Almost the entire 2012 corn crop had gone through the silking stage as of July 29, well ahead of average. A total of 94 percent of the crop silked in the latest week, up from 78 percent in the same week a year ago. The crop continued to dough and dent well ahead of average as well. A total of 37 percent had reached the dough stage in the latest week, up from 17 percent as the 2007-11 average for the date. The crop was 13 percent dented in the 18 states, up from 3 percent as the five-year average, the USDA said.

Soybeans also were progressing ahead of average. In the 18 major soybean states, a total of 88 percent of the crop had bloomed as of July 29, up from 72 percent in the same week a year ago and above the 2007-11 average of 75 percent. Some 55 percent of the crop was setting pods, up sharply from 29 percent in the same week a year ago and 35 percent as the 2007-11 average.

The spring wheat harvest was 28 percent completed as of July 29, well ahead of 1 percent at the same time last year and 3 percent as the 2007-11 average for the date.