- You just saw one example of why wheat is turning yellow, here is another
- No. 2 - This is probably during March or April. The key is
the definite pattern of yellow streaks next to the dark green wheat. What do you think
might be the cause of this problem?
Answer #2
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| Here’s another field where yellow spots are developing. No.
3 - Wheat here had a normal appearance during the fall and winter. Toward the end
of March, these yellowish areas begin to appear and within a week or so some of the plants
in the affected areas begin to take on a brownish cast. When we look closer, we see that
some of the lower leaves are wet, shiny and sticky. When we look on the lower leaf surface
we find colonies of these small greenish soft-bodied insects. What is this problem?
Answer #3 |
Click on the picture to view full size 
Click on the picture to view full size
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| No. 4 - Wheat is plagued with a variety of leaf spots. On
many of the leaves in this field, you find these tan to brownish lesions or blotches. You
also can see that these brown blotches contain tiny, well-separated, black speckles. What
is the name of this problem? Answer #4 |
Click on the picture to view full size |
| No. 5 - Here is another leaf disease. On these leaves you
see tan to brown colored blotches. You see no evidence of fruiting bodies within the brown
spots, but you sometimes notice a thin yellow border or halo that has developed around the
dead area. Name this disease! Answer #5 |
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| No. 6- Here is a typical spring question on farms where wheat is grazed.
When should I remove the cattle from wheat pasture if I want to minimize grain yield
losses? Is it (A) at 100 degree day heat units, (B) when the first hollow stem can be
determined, ( C) when the first joint is visible or (D) when the first joint is still 2
inches below the soil surface. Answer #6 |
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| No. 7 - Here is a weed problem. Notice the vining stems
and leaves that are in the form of an elongated heart shaped pattern. What is this weed?
Answer #7
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| No. 8 - Here’s a field somewhere in the western
third of the state during late April or May. It is in the jointing stage of the
development. Recently plants have taken on an off-color appearance. As you look from the
edge of the field, you’ll notice that the plants in the affected portion are more
bushy and prostrate in appearance than is normal for wheat. Many of the plants are stunted
and off color. Close up on some leaves, you will see distinct alternating green and
white longitudinal stripes. Also, you’ll notice that some leaves are tightly rolled.
On many of these rolled leaves, you’ll notice a very distinct pinkish to purplish
color. What do you think is the most likely cause of
these symptoms?
Answer #8 |
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Click on the picture to view full size
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| No. 9- Here is another case of yellowing in a field
where development is approaching the boot stage. We see patches in this field where plants
are stunted and yellowish. In examining the affected plants, you will see that the
leaf tips are yellow or purple, but the leaf bases tend to remain green.
What is causing this problem?
Answer #9 |
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Click on the picture to view full size
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| No. 10- This winter annual grass comes up after
the wheat is planted in the fall and produces cylindrical shaped seed capsules that are
stacked in the seed head as you can see in the picture:
What is the name of this plant that is closely related to wheat and sometimes
crosses with wheat to produce hybrid plants with intermediate type seed heads like these:
Answer #10 |
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Click on the picture to view full size
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| No. 11 This field looked normal earlier, but you have not
seen it since it has started to ripen. Now as you approach the field, you become aware
that something is wrong. Instead of ripening evenly across the field, you see these
irregular spots throughout the field where the wheat has a distinctly off-color brownish
appearance. The wheat in these spots headed out, but it has no grain in the heads.
Looking closer, you can see that the stems have an unusually reddish appearance, and as
you look closer, you can see that the nodes (the joints) are unusually large (swollen) and
tend to have a dark greenish color. What do you suspect might be causing the wheat to
produce these symptoms?
Answer #11
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Click on the picture to view full size
Click on the picture to view full size
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| No. 12 A few nights ago, the temperature dropped below
freezing for a while. In this picture, imagine that this is the growing point from a plant
in your field. Does this plant look normal or is it freeze damaged? Answer #12 |
Click on the picture to view full size |
| No. 13 We are going now to a neighboring field to examine a different set
of plants. Judging from this picture, do you see signs of freeze damage here? Answer #13
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