Saving seeds from corn

I’ve never grown corn before, I planted some sweet corn July 1st and it looks ready to eat.

I peeled one back a bit and there was a caterpillar  eating the top. I assume you just cut the top off and eat it anyway?

Anyways my real question is, if I want to save seed from this, I can’t just leave it on the stalk can I? Will the caterpillar eat all the corn and leave me with no seeds?  What exactly do I need to do here?

I have no idea how much corn you planted, but unless just a small row, it's highly unlikely the caterpillar(s) can eat it all before the caterpillar moves on to the next stage of its life, which should be within the next month I'd think in Missouri. Leave some on the stock. Again, not knowing how much you planted nor how much seed you want, Maybe leave 5-10 percent of your ears and stocks standing to harvest your seed.

Melissa Ferrin wrote:I have no idea how much corn you planted, but unless just a small row, it's highly unlikely the caterpillar(s) can eat it all before the caterpillar moves on to the next stage of its life, which should be within the next month I'd think in Missouri. Leave some on the stock. Again, not knowing how much you planted nor how much seed you want, Maybe leave 5-10 percent of your ears and stocks standing to harvest your seed.

Super small patch, maybe 8x10 feet

At my place, corn ear-worms eat less than 10% of the seeds on a cob. By the time sweet corn reaches the fresh eating stage, the seeds are viable. So you could eat some of the cob, and save some for seed.

Also wondering about seed saving, I enjoyed this article from Southern Exposure Seed Exchange on saving corn seeds.
Building on the question about those caterpillars (thanks for clarifying that, Melissa), I found that some of my corn did not have "cutworms." Is it possible that those seeds have some resistance and could be selected for that genetic trait? Also, I plan to keep a water feature near the corn field next year in hopes that the wasps will take care of some of the cutworms. Are wasps actually helpful cutworm predators?

Eric Hammond wrote:I’ve never grown corn before, I planted some sweet corn July 1st and it looks ready to eat.
I peeled one back a bit and there was a caterpillar  eating the top. I assume you just cut the top off and eat it anyway?

Here in SE Indiana, I have terrible problems with worms in corn. I always called them ear worms, but I think they be the same as or also called fall army worms. They used to mostly be a problem in later season but now days they are here by mid-June. They generally enter the ears apparently from eggs laid in the silks and can pretty much destroy an entire ear. If left alone they usually travel mostly vertically eating and destroying two or three rows as they travel down the ear. Sometimes or if they've already traveled the whole length, they will start going around the ear instead. Kernels that are not eaten tend to get rot and molds that starts in the damaged kernels, and I think from the accumulated worm poop. Other small beetles and the like often take advantage of the situation and join in the feast as well. There is generally just one worm per ear but occasionally two or three.

Eric Hammond wrote:
Anyways my real question is, if I want to save seed from this, I can’t just leave it on the stalk can I? Will the caterpillar eat all the corn and leave me with no seeds?  What exactly do I need to do here?

With sweet corn which unfortunately seems to be one of their favorites, it is generally harvested in early stage of maturity so only the tip of the ear is damaged by that time, and the rest is fine to eat. Getting nice clean seed is another issue because they keep eating as the kernels keep maturing. You can open the husks and remove the worms but in my humid climate once an ear has been damaged or opened the molds and stuff just keep getting worse. While the seed is viable at about the same time it is ready to eat, I like to let it mature a bit more if possible because I think it makes a more robust seed and I think it last longer in storage which allows me to keep seed for a few years if I want to.  

Anyway, like I said these worms have become a terrible problem at my house. Right now, I've moved entirely away from sweet corn, which seems to be their favorite and flour corn which they seem to like second best to flint and popcorn. They will attack flint and popcorn, but damage is usually less than on the others. I have also discovered varieties of corn that have some natural resistance to the worms and introduced those genetics into my crop.

If I was going to grow and save seed for sweet corn, I would look for varieties described as having tight husks and good tip cover. Some corn has "flag" ears, that have little tufts of leaf growing off the tips of the ears. Those seem to be a little bit more resistant. In saving seed, I would select in favor of those traits. In the event I found an ear that was not attacked when most others were, I would favor it in my saved seed.

As far as the wasps go, I also have bad infestations of cabbage worms and I see the wasps preying on them. Another type of what I believe is a small wasp lays its eggs on those large tomato worms, but I have never observed any kind of natural enemies to the corn ear worms.

when I lived in the US I worked on a local organic farm as part of my CSA and the sweet corn worms were everywhere. I was told that growing corn organically meant worms, basically. We picked off what we could but I know ever since then I always just cut off the tops where there were any worms, washed it off, and didn't worry about it. They usually only seem to appear right at the top and don't generally eat the whole darn thing.

Then I moved to this corner of South America, where sweet corn isn't widely grown, and I suspect it has to do with bug pressure. Worms are everywhere, but still mostly limited to the top (except for in stunted ears, where they do seem to run rampant). I still just cut off any damage and eat the rest.
Saving seeds from the corn that resisted best is good (you have to save some anyway), but I suspect it has more to do with coincidence- weather, wind, etc probably determine more when and where the worms appear. Still, maybe you'll learn something! keep us posted!

Tereza Okava wrote:but I suspect it has more to do with coincidence- weather, wind, etc probably determine more when and where the worms appear. Still, maybe you'll learn something! keep us posted!

That is a very big issue for me in my landrace gardening. I have limited space so can only grow small populations of a lot of crops. In a very large population, a noticeable difference might more possibly be genetic. In a small one though with fewer plants to observe, you can never be sure the difference between one and another isn't just by environmentally induced random chance.

This is great information guys thank you!

It brings up another question, how do people grow and sell sweet corn, it’s not exactly ideal for the customers to open up a corn and have a worm in it, is it safe to assume all the corn I see for sale is sprayed with some sort of pesticides?

I have worms in sweet-corn I buy at the market sometimes...maybe 1/4 ears. I just buy extra and unless it's badly infested and damaged, we just cut it off and eat.

I'm in Illinois & have about the same climate as Mark Reed above.  I will second all he has said above as my experience as well.  We just call them corn ear worms, but they do go by different names.  I am currently selecting for tight husks & tip coverage as well as I can amongst other traits, since the worms can be pretty devastating to small crops.  I've read that to avoid spraying you can put a few drops of mineral oil on the tip of the emerging silks, but I haven't tried it yet, and don't spray.  The little I know about commercial sweet corn is it is sprayed upon silk emergence.  It would sure be nice to have perfectly full ears without spraying & without ear worm damage.  That's why many of us are trying to breed better corn.  Until we find that magic combination of genes that prevent the worm damage, I'll just have to keep cutting off the end of the ears & enjoying the remaining 3/4 of the ear.  Still good results for sharing with nature, but I'd rather not have to, lol.

Eric Hammond wrote:is it safe to assume all the corn I see for sale is sprayed with some sort of pesticides?

this is what I assume. There seem to be some "organic" alternatives (if you do some searches there's a lot of ick targeting growers of sweet corn) but personally I wouldn't use them in my garden. To be fair, my biggest concern is pollination, not worms, and the last thing I want to be doing is spraying some sort of bug killer on the corn silks. I grow small patches of corn and even despite manually moving pollen onto those silks, I still will take the help of every ant, bee, and bug that wants to carry some for me.

I forgot to mention, if you are only interested in saving enough corn seed for next year's crop, rather than breeding for improvements, then you could try this:  

Cut off the ear worm damaged end of the cob at the same time that you are shucking the corn husks for eating or freezing.  Save the damaged ends in a shallow cardboard box such as a beer flat or printer paper box lid.  Place the box in front of a fan in a warm garage or other outbuilding away from flies if possible (if not possible, just leave to dry outside, but out of the rain).  Once dry enough (a couple weeks), gently press your thumb on a kernel & it'll pop off.  Do this to all of the clean mature kernels (emphasis on mature) and put them in an open top paper bag or small cardboard box to finish drying for storage.  Once hard & dry enough to shatter when hit with a hammer, you can store the seed in a glass jar for next year's planting.  

If you do the math, you'll find that for every 1 seed you plant, you'll get 1-2 ears.  From those 1-2 ears, you'd normally throw the damaged tips away when husking.  If you save & dry those damaged tips, you could get anywhere from 10-20 good seeds from each one.  So, you'll have enough dry seed this way to potentially grow two back to back crops (depending on your growing season) with seed left over to give your neighbors.

For small plots, you could get away with this for a couple years I'd think before needing to introduce fresh seed due to inbreeding depression.

Cy Cobb wrote:I forgot to mention, if you are only interested in saving enough corn seed for next year's crop, rather than breeding for improvements, then you could try this:  

Cut off the ear worm damaged end of the cob at the same time that you are shucking the corn husks for eating or freezing.  Save the damaged ends in a shallow cardboard box such as a beer flat or printer paper box lid.  Place the box in front of a fan in a warm garage or other outbuilding away from flies if possible (if not possible, just leave to dry outside, but out of the rain).  Once dry enough (a couple weeks), gently press your thumb on a kernel & it'll pop off.  Do this to all of the clean mature kernels (emphasis on mature) and put them in an open top paper bag or small cardboard box to finish drying for storage.  Once hard & dry enough to shatter when hit with a hammer, you can store the seed in a glass jar for next year's planting.  

If you do the math, you'll find that for every 1 seed you plant, you'll get 1-2 ears.  From those 1-2 ears, you'd normally throw the damaged tips away when husking.  If you save & dry those damaged tips, you could get anywhere from 10-20 good seeds from each one.  So, you'll have enough dry seed this way to potentially grow two back to back crops (depending on your growing season) with seed left over to give your neighbors.

For small plots, you could get away with this for a couple years I'd think before needing to introduce fresh seed due to inbreeding depression.

This is great advice thank you

My family used to grow organic sweet corn without ear-worms by placing a large UV-light bug zapper near the corn patch. The ear-worm moths were attracted to the light, fried with intense bursts of electricity, and served warm to the chickens (who wouldn't leave their roost at night to eat them, so had to have them cold in the morning).