I grow Kandy Korn every year and get great results in a year that the weather cooperates. This past year it rained so much did not get good pollination and kernel growth--lots of empty spaces on some of my ears. And as for worms, timing is important if they bother you. Planting early or late will keep them to a minimum. We just ignore them. Most ears have a worm in the tip and we just cut them out and either feed them to the chickens or roast them in a hot compost pile. Dawn and George will be along with a more detailed answer I am sure.

Hi Dawnrenee,

Welcome to Oklahoma Forum here at Garden Web!

It is possible to control corn earworms organically here in Oklahoma, but that doesn't necessarily mean it is easy. You have to be very proactive and vigilant and take a multipronged approach.

Small ears would be a different problem and normally are either a genetic issue (i.e. the variety planted only has the capacity to produce ears of a certain size) or a fertility/water issue.

Here's a list of the various methods you can use to combat (and usually mostly defeat) corn earworms in Oklahoma.

1. Plant early. Plant as early as you can based on your soil temperatures and weather forecast. The moths that bring us corn earworms arrive fairly early here, but it is possible to plant early enough that your corn is past the green silk stage before they arrive.

Here in extreme southcentral OK in zone 7b, I can plant as early as the third week in March some years and, with an early planting date like that, if I plant a very early corn like Early Sunglow, I often can harvest corn on Memorial Day weekend, well before I am seeing earworm issues here.

Even with a later planting date or with the use of a variety with a longer DTM, you usually can harvest in June. The goal is to get your corn past the green cornsilk stage because the moths only lay their eggs on gree silks. Once the silks are browning, the corn earworms are less of an issue...although corn borers sometimes are. (Spraying the ears with Bt or spinosad once or twice a week can help with the European corn borers that like to bore their way right through the corn husks to get to the kernels.)

2. Use a pheromone trap to alert you to the presence of the moths and have trichogramma wasps handy and ready to put out. Once you hang the wasp egg cards outside, the wasps hatch in a day or two and begin attacking the small moth larvae. For the best results, put out trichogramma wasps weekly to protect your corn crop.

3. In addition to trichogramma wasps, you can release other beneficial insects that attack the earworm larvae including minute pirate bugs and green lacewings. It helps if you have some of the small-flowered plants that encourage these small beneficial insects to stick around. There are a lot of insectaries that sell beneficials in small quantities to home gardeners. If you need a list of them, let me know.

4. You can spray your cornsilks/corn ears once or twice weekly with a Bt 'Kurstaki' spray or inject beneficial nematodes (available online from places like Gardens Alive or Planet Natural) once or twice a week. Do this as long as you have green corn silks.

5. Once the green corn silks are turning brown, you can switch to the use of mineral oil (corn oil or soybean oil are preferred, and food grade oil from the grocery store is just fine) applied to the corn silk area right where the silks emerge from the ears once or twice a week. To increase the effectiveness of the oil, you can mix Bt with it. Use an eyedropper to apply 4 or 5 drops of oil to each ear. The soil will smother the ear worms. You cannot apply the oil until the silks are browning OR you can apply it while still green, but you may get poor pollination on the upper 1/2" of each ear.

You also can spray the silks/ears with a spinosad product.

6. If you still are seeing significant corn earworm damage despite all the above, you can use a botanical insecticide like rotenone, pyrethrum or neem, although I personally do not use rotenone because of its danger (organic doesn't automatically mean 'safe') and especially because of its possible/probable association with some neurological diseases/illnesses.

7. During the fall, winter and spring, rototill, plow or hand dig the part of the area where you grew corn. This will expose overwintering pupa to wind, weather and pests and can help reduce how many 'local' ones survive and emerge in the spring.

Some years I have to take a lot of the above actions to combat the earworms, and some years I don't have to do much of anything at all.

I have the best luck, year in and year out, with early plantings and with tight-husked corn varieties like Silver Queen or Texas Honey June. I like to plant Early Sunglow for a very early 'harvest by Memorial Day' sweet corn and then often Silver Queen, Country Gentleman or Serendipity for a second spring corn.

For a fall crop, I plant in mid-summer for a fall harvest and generally don't have much of an earworm issue with that crop, although it always pays to be vigilant.

If you want to read more about combining mineral oil with Bt 'Kurstaki', I've linked a document from Johnny's Selected Seeds. It actually is intended to describe how to use the oil/Bt mixture with their nice (and expensive, for a home gardener) Zea Later applicator. However, you can follow their directions to mix the oil and Bt and then apply it using a sprayer or eyedropper and don't have to have a Zea Later applicator to use the oil/Bt combo.

Small ears are a whole different issue. Some corns (and this is most especially true of the early sweet corns) just produce smaller ears. I have found ear size to be affected by low moisture or low fertility, so be sure those aren't an issue. Planting late can result in small ears because of the heat, especially if your corn is planted so late in the spring that it is pollinated in high temperatures which impede pollination and gives you half-filled or poorly filled ears.

In crops that are maturing from mid-summer on and into the fall, you may have more issues with European corn borers or fall armyworms. Often they tunnel right through the husks on the sides of the ears, so the best way to combat them if you don't have trichogramma wasps or green lacewings around is to spray the entire ear with Bt 'Kurstaki', spinosad, neem, pyrethrum or rotenone (use the latter at your own risk).

I generally don't have earworm problems or size issues with non-sweet corns like field corns and ornamental corns. Most years we harvest enough sweet corn that we're able to eat all we want throughout the summer and freeze enough to last us all winter and spring.

Finally, when ears do have earworms I don't get all excited about it. I just remove the earworms and put them in a plastic bowl so I can take them out to the chickens later and cut away the damaged portions of the ear and use the rest of the corn from that ear.

Hope this info helps.

Dawn

Here is a link that might be useful: JSS's Zea Later Corn Information With Oil/BT

I have a lot of trouble with corn earworms and unpollinated ears. After being on GW this fall and winter, I'm going to try hand pollinating and the oil/Bt treatments this next year. I just hope my corn isn't silking the week I'm away on vacation!!

Tigerdawn,

Tell me about how you plant corn because unpollinated ears are not common in Oklahoma unless your are planting in 1 or 2 long rows (blocks are better), have severe issues with a lack of wind movement (is that even possible in OK?) or your corn is pollinating at high temps which cause the pollen to be sterile (in which case hand-pollination won't help). Hand-pollinating is a lot of work and shouldn't be necessary unless you're engaging in an extraordinary effort to save a very rare corn.

Dawn

Well, I planted my sweet corn in 5 rows of 6 or something to that effect. I planted it in late April I think. After the silks had turned all brown I started watching but the ears never got thick so I looked inside and the few kernals that were there were past the eating stage. I suppose this last year it didn't do well because of the rain.

The year before I did parching corn in the same configuration and had more success but I still had mostly partial ears and almost every one had an earworm in it.

I had originally decided to skip the corn altogether in 2010 but the talk of hand pollinating and oil/Bt treatments made me think I could do it.

Thank you so much for passing on your wisdom! Armed with all of this great info, I think I will EXPAND the corn plot!

Tigerdawn,

It might have been rain, but I've never had rain impede pollination. I have had unexpectedly hot weather in May affect it though.

The only way I can imagine somebody here having a lack of wind that might hurt corn pollination would be if your corn is growing in a suburban back yard where houses, sheds, wooden privacy fences and the like really impair wind movement in back yards. Where I live out here "in the sticks", the problem is diametrically opposite.....a lot of wind that tends to cause cornstalks to lodge (blow over) especially during a severe thunderstorm or strong dust storm.

Because you mentioned small ears and pollination issues, I'd guess your soil might be low in nitrogen or that there is some issue with your soil that impedes nitrogen uptake. Smaller ears than expected on a given variety is usually caused by low nitrogen levels or by planting corn plants too closely together, such as the closeness used in Square Foot Gardening. Corn plants are heavy feeders and need a lot of nitrogen and wider spacing within rows/between rows gives you larger ears while closer spacing gives you smaller ears.

Also, the corn needs to pollinate before daytime highs regularly exceed 90 degrees. (Some corn varieties will pollinate well above 90 degrees, but many won't.)

Maybe Jay or George or Dorothy or someone who regularly grows corn will have other ideas about pollination issues or small ears.

Dawnrenee,

You're welcome. Always glad to help.

Talking about gardening in December tricks my mind into believing spring is coming soon and the sun is shining outside (neither of which is true, LOL).

Dawn

Our corn bed gets a layer of chicken litter every year so gets plenty of nitrogen, so small ears is never a problem for us. Kandy Korn has large ears. We used to raise Early Sunglow and that corn does have naturally small ears, as you mentioned.

I thought it was too much rain that caused our pollination problems, but this year we had such bad germination--and that was too much rain, I think--and too much predation--something ate some of the seed before it came up, tunneling down the row--that we planted 4 times instead of the usual two. So perhaps it was the high temps--we had our 100's in mid June this past summer, earlier than usual--that made for the spotty ears, as part of our corn came off much later than usual. In a normal year we spend 4th July putting up the most of the corn. This past year we had corn in early August, and it was that late corn that was so spotty.

Dorothy,

I suppose rain could play a role in poor pollination and I can envision 2 or 3 ways that it might happen, but you know I am not a corn expert and so my three suggestions below are just that...suggestions for how it could happen.

First, if heavy rain falls before the green corn silks emerge, and the plant roots are waterlogged for a fairly long period of time, the plant growth may be stunted. Severe stunting could result, perhaps, in poor pollination. This would be more of an indirect cause--stunted plants producing poorly.

Secondly, if your corn plants reach the tasseling stage and you have continual rainfall on the exact days the anthers are shedding pollen. If I remember correctly, anthers don't shed on rainy days because the rain makes the pollen 'sticky' so it doesn't fall from the anthers to the silks. Since pollen is only viable for a day, I can see where you might get impaired pollination if your plants stayed wet all day every day that the anthers are shedding pollen. I've never seen that happen here though....we have always had good pollination except when it is hot at the wrong time. I do think it could happen though. This probably would be the most direct way rainfall could impede pollination. I think it would be rare here for that to happen, because normally we have dry days mixed with rainy days.

Usually, poor pollination results from lack of water, high heat at the time anthers are shedding pollen, low nitrogen, some diseases, pest damage (like when earworms eat the green silks before pollination occurs) or if a hail storm damages silks or tassels before pollination is complete. Those of you in consistently wet areas might have rain-caused pollination issues with corn that I never see here in generally hot and dry southcentral OK. However I've never seen excess rain mentioned in literature as a cause of poor pollination, and I've never had pollination issues here that I could trace to rainfall being high while pollination was occurring even though we often have heavy rain in May which is normally when my corn is pollinating.

Dawn

Howdy folks, it's hard to check in lately. I'm working a new job with new hours. This year was a TERRIBLE year for corn, here in Tahlequah. Our corn only produced nubbins. I imagine the pollination problem has something to do with the extremes in heat we experienced.

Here's what I do for ear worms, though they are generally not that great of a problem for me. I go through and put a few drops of mineral oil on the ear, where the silks go into it. The oil catches the ear worm larva as they enter the ear, and it suffocates them: end of problem.

George

I don't normally grow corn because it takes a lot of space for what you get from it, but I am going to try a small patch of dent corn this year.

George - I thought mineral oil had been proven to be a carcinogen, and also had adverse effects on the nervous system. I try to avoid anything with mineral oil. Do you think another oil would work as well? I would feel safer using a veggie based oil rather than a waste by-product of the petroleum industry. Sorry if I sound paranoid here, but that's just my thoughts.

Carol,

Many people nowadays use either corn oil or soybean oil instead of mineral oil. I've used corn or soybean or even canola oil for years, so you certainly can use any of those instead of mineral oil.

In fact, the use of mineral oil is prohibited for farmers and market growers who raise/sell crops under the Organic Certification program.

Dawn

Hmm... I just learned something ;)

George,

I learn something here every day. : )

Until Carol posted it, I didn't realize mineral oil (and for those who don't know, baby oil generally is 100% mineral oil) was considered a carcinogenic.

I just used veggie oil instead of mineral oil because mineral oil is a petroleum product and corn oil is a food product.

Dawn

I do live in suburban OKC but my backyard is usually pretty windy. I've had to replace my greenhouse door 3 times now. The heat or a well timed rainstorm must have done my 2009 corn in. The earworms were definately the main problem in 2008. I will not worry about the pollination then and just do the oil treatments.

Also, I will actually USE the organic fertilizer I bought for my veggies last year. ;^) I got the veggie fertilizer from GardensAlive.

I am ready for Spring and we haven't even made it to Christmas yet! How will we all survive?! LOL!