WASHINGTON — Corn crop conditions were deteriorating sharply in a number of key growing states, including Illinois, Indiana and Ohio in the Central states, the US Department of Agriculture said in its Crop Progress report released July 16. Corn crop condition in top-producing Iowa took a serious hit as well, with a 10-percentage-point drop in the crop’s good to excellent rating.

The corn crop in the 18 major growing states was rated 31 percent good to excellent as of July 15, down from 40 percent a week earlier and compared with 66 percent at the same time last year, according to the USDA.

Soybeans saw slightly less precipitous declines in good to excellent conditions in the current crop progress report, but the trend was definitely toward a less healthy crop. Soybeans in the 18 major states were rated 34 percent good to excellent on July 15, down from 40 percent a week earlier and well below 64 percent a year ago, the USDA said.

The percentages of corn and soybean crops rated very poor to poor jumped sharply as of July 15 as well. Corn in the 18 states rated poor to very poor was 38 percent, up from 30 percent the week ended July 8 and well above 11 percent last year. Soybeans rated poor to very poor were 30 percent as of July 15, up from 27 percent a week earlier and 10 percent a year earlier.

Drought, called the worst since 1956, has been unrelenting in the Corn Belt for weeks, although growing conditions to the north and to the west in the Midwest and in parts of the South have been more favorable — at least so far. Crops such as oats and rice, for example, appear to be in better shape than the row crops, but the acreage belongs to corn and soybeans.

Good to excellent ratings for corn in the eastern Corn Belt continued to tumble as of July 15. In Illinois, only 11 percent of the crop was rated good to excellent, down from 19 percent in the week ended July 8. A total of 56 percent of the crop was evaluated as very poor to poor, up from 48 percent in the previous week. In Indiana, only 8 percent of the crop was rated good to excellent in the week ended July 15, down from 12 percent in the previous week. A total of 71 percent of the Indiana corn crop was rated very poor to poor, up noticeably from 61 percent in the previous week, the USDA said. In Ohio, 19 percent of the crop was deemed good to excellent, down from 28 percent in the previous week, while 47 percent was rated very poor to poor, up from 36 percent a week earlier, the USDA said.

Iowa still had 36 percent of its corn crop rated as good to excellent in the latest week, down from 46 percent as of July 8. A total of 27 percent was in very poor to poor condition in the latest report, up from 18 percent the prior week. Although well above states further east, other Corn Belt states also saw sharp declines in good to excellent ratings for the week ended July 15 as well, including Minnesota, down 10 percentage points at 67 percent, Nebraska, down 4 points at 43 percent, and South Dakota, down 23 points at 33 percent.

The corn crop this year was planted early and pollination, which occurs best in relatively temperate weather, also occurred early but coincided with ongoing very dry and hot conditions in the Eastern Corn Belt initially but spreading west in July. The USDA reported that silking was 93 percent complete as of July 15 in Illinois, drastically higher than the five-year average of 53 percent at the same time of year. In Indiana, 79 percent of the crop had completed silking for the same period, up from only 39 percent for the five-year average. Ohio’s corn crop silking was 67 percent complete as of July 15, also well ahead of the 29 percent five-year average. Soybean crop conditions exhibited noticeable declines as well in the period ended July 15, the USDA said.

In Illinois, only 17 percent of the crop was rated good to excellent in the latest week, down modestly from 20 percent in the week ended July 8, the USDA said. A total of 41 percent of the Illinois corn crop was rated very poor to poor as of July 15, down slightly from 42 percent the week ended July 8.

The good-to-excellent portion of the Indiana soybean crop was only 11 percent in the latest week, down from 14 percent in the previous week, the USDA said. Very poor to poor conditions afflicted 57 percent of the Indiana crop in the latest week, up from 51 percent a week earlier.

Ohio’s soybean crop was rated 22 percent good to excellent as of July 15, down from 27 percent good to excellent in the previous week. Very poor to poor ratings described 42 percent of the crop as of July 15, up from 36 percent as of July 8.

In Iowa, also usually the top soybean-growing state, a total of 38 percent of the crop remained good to excellent in the latest week, down from 48 percent in the previous week. Only 20 percent of the Iowa crop was rated very poor to poor, although that represented a gain from 15 percent in the week ended July 8.

Progress in blooming as of July 15 significantly outpaced both last year and the five-year average, the USDA reported. For the 18 major soybean-growing states, a total of 66 percent of the crop was blooming as of July 15, up from 34 percent at the same time a year ago and up from 42 percent for the five-year average.