Weevil life cycle and corn seed long-term storage questions

For the weevil experienced seed savers on here:  Once you shell your dry corn from the cob, with no visible weevils amongst the kernels, and old cobs disposed of so as not to harbor weevils nearby, how long should you wait before you deem your highest quality future seed "weevil egg free"?

In my case, I've hand shelled my corn, removed any suspect, gnawed on, molded, or dirty kernels, and am keeping the best seed for future breeding projects.  I intend to keep it in the freezer for long-term storage & know that that's one way to kill weevil eggs, but I was just curious if there was a rule of thumb while it's drying down, like if no weevils are present after a month or room temp open air storage, then there are no eggs in/on the kernels?

Also, to those that freeze their corn for long term storage, do you put it through a dehydrator to remove moisture, or is ambient temp & air exposure for a month sufficient to maintain seed viability? I've heard that over drying can reduce viability (maybe due to heating element/light?), and under drying can burst the kernel due to the internal moisture expanding.  Some accounts have even sweet corn seed keeping viability for 10 years if kept in the freezer.

To anyone who has kept dent/flint/flour corn in a jar, how long do they stay viable for if kept out of the light at 60-70 degrees?  

Doing a weevil experiment right now! I took all the cobs I saved seeds from and am storing them in an open paper bag. About 2 inches of corn left on each cob. I want to see how the weevils proliferate in unprotected, unfrozen corn from harvest to planting time, inside my house. I hope to see some difference in different seeds to infestations.

Last year I stored my flour corn in a plastic tote in the unheated garage. All the corn had been frozen for at least a few weeks in the freezer prior to storage in the tote. There were no signs of weevils until late summer. I assume very slow growth during the winter months since the garage is often below freezing temps and always quite cold in winter. But by summer there were large numbers.

The source of the weevils was not my corn, but some purchased corn that was stored in the garage for too long and there were hordes of weevils all over the garage before I tossed it. Big mistake buying that corn.

For my seed corn I dry it outdoors in the sun first then put it in the freezer a few weeks. Some small seed bags were left in the freezer from fall to spring until the day before planting, so maybe 6-7 months in the freezer. No problem. I have not tested longer freezing times.

I believe it was in Mollison's old book "Ferment and Human Nutrition" where I read that heating up any seed or grain to 150F for 30 minutes will kill any insects and their eggs in it, but not kill the seed itself, so that it can still be sprouted or planted.  I've used this technique, mostly with my solar cooker, with good results on both home-grown and purchased grains and seeds of many kinds ever since.

Alder Burns wrote:I believe it was in Mollison's old book "Ferment and Human Nutrition" where I read that heating up any seed or grain to 150F for 30 minutes will kill any insects and their eggs in it, but not kill the seed itself, so that it can still be sprouted or planted.  I've used this technique, mostly with my solar cooker, with good results on both home-grown and purchased grains and seeds of many kinds ever since.

Have not tried heating seed. Would never have even considered it if you hadn't mentioned it. It just seems wrong to heat seeds. I would expect it to kill them. I should try heating some and then see if they sprout.

How do you control the temp in a solar dryer? I do have an electric food dryer with a temp gauge I could try.

Just adding a datum: I have killed seeds at temps far lower than 150 (maybe 120), but it was in a dehydrator and they were there for four days or something, not just half an hour. (I've also seen no germination rate drop in seeds at 105 for days and weeks.)

We put our seeds in the freezer as recommended on a lot of prepper sites.

When I sore things in food storage I add some salt.  I dont know if salt would hurt seed germination, though.

I'm not sure about the particulars of weevils in corn, but one general strategy for defeating arthropods is to freeze the seed for some period of time, then bring it out to room temperature long enough for the target bug to restart growth, then return the seed to the freezer to kill those that were at egg stage during the first freeze.

Update to my version of Thom Bri's weevil experiment:

As I shelled my entire season's worth of mixed dent corn in my garage, all less than perfect kernels were thrown into an open topped cardboard box.  This included all stained, dirty, moldy, bug damaged kernels or any that looked less than perfect, as well as a handful of good kernels that fell on the floor as I shelled.  Overall, it contained an estimated 3 gallons by volume.

After a few months, I decided that instead of throwing away the whole box, I'd sort through it to select out all of the good plantable kernels that survived the weevils up to that point.  I did find a few weevils in the bottom of that box, but felt that enough time had gone by that any eggs that were there would've hatched by then.

I sorted through the box kernel by kernel, inspecting for weevil holes, or any other real damage that would prevent the seed from growing.  All told, I ended up with about a half gallon volume of good plantable seed from that entire box.  I'm storing this seed in clear glass jars in my unheated garage so I can glance at it every time I walk by, looking for signs of weevils.  So far, it's been about a month of cold temps with no new hatches.  I don't expect new hatches until spring, but as the summertime temps rise, we'll see if they do hatch anymore after seasonal dormancy.

This may not be entirely scientific, but I think it's a practical test for myself and my purposes for the time being.  If I do this same process of hand grading seed, allowing the hatch, grading what's left, then monitor what's left, I'm sure to learn something along the way.  Even if this study doesn't result in developing a weevil resistant line of field corn many years from now, it's still a worthwhile experiment to pass the time and work toward corn that survived exposure to mold, weevils, frass, smut, lodging, weather, etc. with no fertilizers or chemicals.

On one hand, this goes against the idea of using perfect seed ala "best of the best" genetics.
On the other hand, it embraces the idea of exposing these same "best of the best" plant genetics (same OP gene pool) to stressors on the individual seeds that they have to survive in order to grow the next generation.

I look forward to hearing the results of Thom Bri's parallel experiment mentioned earlier in the thread.  In the end, whatever is left in the jars will contribute to my continued diverse planting seed.  

I'm open to hearing other thoughts, theories, experiments, or questions on this subject if you have them.  

Cy Cobb wrote:Update to my version of Thom Bri's weevil experiment:
I look forward to hearing the results of Thom Bri's parallel experiment mentioned earlier in the thread.  In the end, whatever is left in the jars will contribute to my continued diverse planting seed.  

Good news. I just now looked in my bag of saved seed and cobs and I found a few weevils. So I can anticipate population growth and hopefully enough weevils to select my seed for next spring. I plan to keep the bag going all next year and see if any seeds at all survive to the 2026 planting season.

Glad to hear your experiment is moving along nicely.  I have entirely different seed that I'm growing next year, so I won't need to dip into these seeds in the spring.  That said, I can continue to monitor mine along the same timeline as you for comparison.  This batch is comprised of all dent varieties, so we'll see how different types are affected over time.

Cy Cobb wrote:This batch is comprised of all dent varieties, so we'll see how different types are affected over time.

It looks like dent is more susceptible than flint in my own corn, and I have read some studies that show that is normally the case. My current bag of seed corn is almost all flint though so it won't distinguish.

I should add a few glass gem ears and dent in the bag just to see if my initial impression that they are nearly bug-proof plays out or not. In fact, I am dropping some ears in right now! One glass gem ear and one hybrid yellow dent I scavenged from a neighbor's field after harvest.

Update on the weevil experiment. I happened to look at my saved prime seed corn, which is in plastic peanut butter jars. Both jars are full of weevils! How wonderful. So I decided to just leave them as-is and let the weevils do their damage. Some seeds will survive a few more months until planting, around May 1st. It should be a good, hard selection for anti-weevil.
If there is too much damage, I still have plenty of other saved seeds I can use.

Now that, right there, is taking a positive view on life! My seeds are all bug infested - yesss, free selective pressure! Congratulations on your sunny outlook and bugs.

Seriously, though, I hope your project succeeds in making weevil-proof corn. Please keep us posted!

Eino Kenttä wrote:Now that, right there, is taking a positive view on life! My seeds are all bug infested - yesss, free selective pressure! Congratulations on your sunny outlook and bugs.

Seriously, though, I hope your project succeeds in making weevil-proof corn. Please keep us posted!

Well, last year I had weevils all over the house for months. Thankfully, my wife never associated the little black bugs with my corn!
This is the first year I have actively tried to get weevils to proliferate. Could be I am just selecting for tougher weevils!

I also moved all my stored food corn outdoors yesterday, It's really cold so hopefully it will kill off most of them. Hoping the squirrels don't find my plastic bins!

Thom Bri wrote: Well, last year I had weevils all over the house for months. Thankfully, my wife never associated the little black bugs with my corn!
This is the first year I have actively tried to get weevils to proliferate. Could be I am just selecting for tougher weevils!

I have often wondered about the people who hang their corn by the husks indoors as decor or in braided ropes to wring off kernels as needed.  I like the idea of that, but in my limited experience, weevils prefer being in corn still attached to the cob over shelled corn.  I think the cob holds onto moisture, and gives them places to hide/burrow into.  I'd love to hang my corn in the house, but for fear of weevils getting into my other foods, I have not.  

Cy Cobb wrote:

Thom Bri wrote: Well, last year I had weevils all over the house for months. Thankfully, my wife never associated the little black bugs with my corn!
This is the first year I have actively tried to get weevils to proliferate. Could be I am just selecting for tougher weevils!

I have often wondered about the people who hang their corn by the husks indoors as decor or in braided ropes to wring off kernels as needed.  I like the idea of that, but in my limited experience, weevils prefer being in corn still attached to the cob over shelled corn.  I think the cob holds onto moisture, and gives them places to hide/burrow into.  I'd love to hang my corn in the house, but for fear of weevils getting into my other foods, I have not.  

Corn hanging loose rarely seems to have a problem. Never, as near as I can see. Whether on the cob or shelled, it is corn that is piled up that gets infested.

Thom Bri wrote:

Cy Cobb wrote:

Thom Bri wrote: Well, last year I had weevils all over the house for months. Thankfully, my wife never associated the little black bugs with my corn!
This is the first year I have actively tried to get weevils to proliferate. Could be I am just selecting for tougher weevils!

I have often wondered about the people who hang their corn by the husks indoors as decor or in braided ropes to wring off kernels as needed.  I like the idea of that, but in my limited experience, weevils prefer being in corn still attached to the cob over shelled corn.  I think the cob holds onto moisture, and gives them places to hide/burrow into.  I'd love to hang my corn in the house, but for fear of weevils getting into my other foods, I have not.  

Corn hanging loose rarely seems to have a problem. Never, as near as I can see. Whether on the cob or shelled, it is corn that is piled up that gets infested.

I take this back. I had corn in bundles last year hanging in the basement that got plenty of weevils. Just this minute remembered that.