Corn pollination occurs when the pollen produced by the tassels falls or is carried by wind to the silks. It occurs over a period of days, so not necessarily all of the pollination occurs on the first couple of days that you see silks although often most of it does. If you watch your corn tassels closely, you'll see the anthers emerge. Once the anthers emerge, pollination is imminent and occurs over the next few days. However, sometimes not all corn plants are pollinating at the same time, especially in a wet or cold year when the weather has slowed down some of the plants.

I don't think you apply mineral oil until after the silks have begun to dry and turn brown, and do think it can interfere with pollination if applied too early.

Bt cannot be that hard to find. I see it in many places. It will not be labeled Bt most of the time. It will be labeled "Caterpillar Killer", "Dipel Dust", Thuricide, etc. You may or may not find it in a big box store like WM, but I find it at the Lowe's, Home Depot, Tractor Supply Company, and other feed/seed or farm type stores or nurseries. When you find a caterpillar product, just check the label for Bt in the ingredients list. Most people who work in most stores have no clue that Bt is the ingredient in some of their caterpillar killer insecticides, so if you ask them for Bt, they look at you with a blank expression on their face and say they don't have it. If you ask them for a caterpillar killer that can be used in a vegetable garden, quite often they'll hand you a product whose active ingredient is Bt. The Bt product I bought at TSC last month was in a little white bottle with a yellow/pale green label and black lettering. It is made by "Southern Agricultural Insecticides (says SOUTHERN AG right on the front label) and is labeled as Thuricide Bt Caterpillar Control.

Some of the cutting edge thinkers in organic growing are now treating their corn ears with a combination of mineral oil/Bt (they mix them together themselves) after the silks brown, and Johnny's Selected Seed even carries a machine they developed to perform the task (although it is very pricey for a home gardener unless you grow a whole lot of corn).

European Corn Borers are a whole separate issue. They will bore right through the husks at any part of the ear and do not make entry through the silks like the earworms do, so about all that works with them is to spray the entire ear every few days with Bt, or with a chemical insecticide if you are so inclined. I don't know which chemical insecticide, though, because I don't use them.

I've linked one of the commonly seen Bt product below, and this particular page has a dealer locator so you can enter your zip code and find the nearest dealer within 5, 25, 50, etc. miles. If this brand isn't sold near you, though, I am sure other ones are.

Dawn

Here is a link that might be useful: One Bt Product + A Dealer Locator

Thank you OD for your time and assistance.

Okiehobo,

You're welcome.

Dawn