Corn pests and diseases

Varmit

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Planted corn seed and found most seemed to come along fine. However, now as harvesting is about to happen, it's apparent there will be little or now good ears. Am finding black bugs within the ear coverings as well as something akin to black mold. The kernels are sparse, bright yellow and tough looking. Some ears have no developed kernels, but simply what appears to be prep spaces where they should have grown.
Spraying early on with chili and oil mixtures helped get rid of some visible pests, but others have infested the insides of ears.
Reading material has spoken of spacing further apart and I'll do that next spring. Also, possibly setting out seeds earlier in April may help.
Any suggestions for assisting soil prep or conditioning and anything else I should know, will be greatly appreciated.
Question: What about heat reaction (we've had 110 degree days this summer and I expect to see same next year)? Should I shade the stalks? What is done when there are multiple stalks growing from one seed?
Thank you for all ideas and knowledge.
 

ducks4you

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@Varmit , I don't like the corn SEED I planted this year. I have had very uneven results.
That being said, Corn is the heaviest feeder just behind tobacco.
In order to grow good corn NEXT year, you have to feed and fertilize the bed THIS YEAR.
I suggest that you contact your local CA University Ag Dept Extension office. They can suggest corn that will grow well in your climate, which differs from MY climate.
Indigenous peoples probably grew corn where you live, and they had to live on it.
 

seedcorn

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Quick questions.

How many rows were planted at the same time?
How long were the rows?
How did the seed germinate?
WHEN did you apply the oil to the silks. NEVER apply oil on silks right before pollination or during.

Black mold is from injury-called smut. Some people eat and enjoy it. Imagine birds found the bugs, pulled husks back to attack bugs which caused the ear injuries.
 

ducks4you

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Sparse kernels are caused by poor germination. Try growing bush beans next time at the base or flowers to attract pollinators.
Smut, where I live is caused by poor air circulation.
One more thing...corn is the 2nd highest feeder, in back of tobacco. For 2023 prepare your corn bed by laying down compost now in a big pile. It will go down over the next year and feed your corn. Plant peas first, to put more nitrogen in the soil.
 

Zeedman

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Corn is wind pollinated, so the more plants, the better. A single row, or only a few plants, will result in poor ear fill - especially for plants on the edges. Planting in blocks of closely-spaced rows is helpful, as is planting in hills (groups of plants) rather than rows. My DW introduced me to the latter method; clusters of plants are more likely to pollinate each other... and planting clusters of seeds also helps to overcome problems with poor germination, especially in hard soil. We planted corn in holes 2-3' apart each way (depending upon variety) over-seeding with 5-6 seeds per hill, then thinning to the strongest 3-4.

I used hills 2' apart each way this year for "Painted Mountain", thinning to the strongest 4 per hill. PM has fairly lanky growth, so it can be planted more closely... and IMO should be planted closely, since that helps the poorly-anchored stalks to support each other in strong winds. Although my late planting this year (or closer spacing?) resulted in smaller ears overall, pollination was very good.
20220920_143709.jpg


Another advantage of hills vs. closely spaced plants, is that it provides nearly the same population per area, while allowing access for weeding or harvest. That (admittedly tight) access allowed me to prevent weeds from seeding under the corn. And since the ears for PM ripen over a staggered period, it also allowed me to harvest without damaging still-developing ears. For sweet corn, the hill spacing allows room to spray the silks with BT to prevent ear worms. For some reason, ear worms don't seem interested in PM (not that I'm complaining :rolleyes:).

If corn smut is found (I had 3-4 ears this year) it should be removed as soon as possible & disposed of far outside the garden. If the fungus is allowed to mature & burst open in the garden, the spores can remain in the soil to infect future crops in greater numbers. For this reason it is also good practice to avoid planting corn in the same spot for consecutive years.
 

Zeedman

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@Zeedman are all of those PM or different varieties? i love the colors of all of them. :)
Those are all PM. I may select against the yellow or white kernels in the future though, since those had smaller cobs, and made up nearly all of the spoilage. I'm tempted to try growing seeds from only the long "black" ear in some future year, should I be blessed to have the opportunity.
 

ducks4you

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I should mention that during a drought SMUT carries further among corn plants. Corn likes 1/2 of water/week, so don't skimp on the watering.
My corn was not great. I just harvested 3 Good ears this morning, from over the counter, who knows? sweet corn seeds that I planted in one row. The early harvest variety wasn't worth it, but maybe bc it was grown for seed in a different climate that mine.
I bought my 2023 sweet corn from Jung's, which grow north of me, in Wisconsin, similar climate, just shorter growing season and colder winter. It is related to the corn developed in my county at the University of Illinois, "Illini Sweet."
I hope for a better corn harvest in 2023.
At least the stalks can go to the horses, so nothing is wasted. 😍
 

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