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Sunday, May 1, 2016

Last effective bloom date is near

Sunday, August 5, 2012

While looking over several cotton fields this week, I realized that we don?t have much time left in the season. We have about two weeks left until the last effective bloom date around the middle of August.

This is the last date on which a white bloom can mature into a harvestable boll. This is the average date but the time may be longer or shorter depending on the temperatures for the remainder of season. So I looked on the Climate Prediction Center?s website to get an idea of the temperatures and rainfall through October. The forecast is for above average temperatures through October and we will probably have below normal rainfall.

Looking at the normal distribution of squares, blooms, and bolls, the first four weeks of bloom are critical. During the first week of bloom, 94.1 percent of the blooms will develop into bolls. This is 16.8 percent of the total bolls for the season. During the second week, only 77.7 percent of the blooms will set, but with the higher blooming rate, this will be about 40.8 percent of the total bolls. During the third week of bloom, only 43.1 percent will set but this is 27.2 percent of the total bolls. During the fourth week, only 20.7 percent of the blooms will develop into bolls, and this will be about 10.9 percent of the total bolls. So during the first four weeks, almost 96 percent of the bolls are being set.

So a quick recap, early blooms set more bolls because they are usually first position bolls which receive more nutrients from the plant and because there is not much competition from other blooms. As the season progresses, the blooms that will mature into a boll will decrease due to the boll load of the plant. There are only so many bolls that the plant can support.

But this year has not been normal. With the drought, we do not have much potential for the non-irrigated cotton. In looking over fields, I noted that most fields are blooming at the top of the plant. This normally happens much later in August. Another observation of the non-irrigated cotton is that it is not setting much fruit. The bolls that are being set are generally smaller than normal. Also much of the non-irrigated cotton is showing nutrient deficiencies since the roots can?t pick up the nutrients from the soil.

According to the Missouri Crop Progress and Condition Report for the week ending, July 29, the cotton condition was 12 percent very poor, 31 percent poor, 42 percent fair, 13 percent good, and 2 percent excellent.ˇIn my opinion, the non-irrigated cotton is really making an impact on this report. Some of the irrigated cotton really looks good, but it has been very costly to keep the fields irrigated. So even if the producers have irrigation, they are still cutting back due to the extra cost this year.

More than half of the counties in the United States have been designated as disaster areas mainly because of the ongoing drought that has been ravaging the nation. This will get worse as the season progresses. In looking at the Drought Monitor, Missouri is 100 percent in the severe, extreme and exceptional categories. At this time last season, we had reached the abnormally dry category due to all of the excess rainfall and flooding. What a difference a year makes.

While the showers that we have received might have slowed irrigation slightly, we have such moisture deficient in the topsoil and subsoil that the benefit just doesn?t last long. Again, the forecast through October is for higher than normal temperatures and lower than normal rainfall.

Last year, Missouri cotton farmers had an unfortunate year in that the final yield was only 969 pounds per acre. This was the lowest yield in over five years. The lower yield was because of the excess moisture and the later planting date. So I am interested when the projected yields appear in the Cotton and Wool Outlook.

This year, it has been observed that bacterial blight has been found in a few Southeast Missouri by Dr. Al Wrather. Dr. Wrather commented in late June that this disease was found for a second year in a row. Symptoms of bacterial blight have been observed on cotton plants in some southeast Missouri fields. The symptoms are black, angular-shaped spots visible on both sides of the leaves. These spots are slightly smaller than a pencil eraser, and many spots may merge to kill large parts of leaves. The diseased tissue will remain black, and the infected leaves may begin to turn yellow and then defoliate if infection is severe. So far this disease is only on lower and middle plant leaves. It will probably not lower yield if only a few lower leaves are damaged, but it will lower yield if it spreads to upper plant leaves and especially if it spreads to bolls and causes boll rot. Before last year, it had been a long time since this disease has been seen.

I can remember that this was a disease that I saw quite a lot during my early career back in the 1970?s. In fact, it disappeared due to having resistant varieties and the acid delinting process killed the bacteria on the seed. Since, it is seed transmitted; I am unsure why this disease is making a comeback. The good news is that it is not causing widespread problems.

The heat units are really driving this year?s crop so I suspect that due to the earliness that we have little chance to set the late season blooms. On several occasions, I have tagged blooms on the last effective bloom date and it is rare that they will make it if the environmental conditions are unfavorable or there is a heavy boll load. So I don?t expect much change for the remainder of the season.

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