Controlling codling moth organically

[Purrfluff]

Every year our apples have been infested with codling moths. I usually use the apple for something like apple butter so I can cut out the gross parts.

But this year I'd like to reduce the codling moth damage. The apple tree has already blossomed and started to set fruit. I hadn't been paying attention and so I didn't mess with the tree until now. Also, I didn't want to do something that might kill honeybees.

I have the following insecticidal products available: BT, All Season horticultural oil, spinosad, pyrethrins, and neem oil.

After doing some reading it sounds like malathion or sevin would be the best control for codling moths. And while I am not utterly opposed to using those I would prefer not to. The flowers are gone so the honeybees are probably safe but I don't want to waste a bunch of ladybugs either.

I know that BT will kill the worms without damaging anything else. Unfortunately I've also read that because the moth eggs are deposited inside the apple the BT doesn't really do anything to them.

I've heard spinosad is pretty effective against the worms but I will run into the same problem as with the BT. I've read that spinosad is an effective contact poison when wet. But once it dries an insect has to eat the stuff for it to kill them. Again, the little bastards are inside the apple.

Pyrethrins are, I think, a contact insecticide. So this might be my best bet. The downside of the pyrethrins are that I don't know if it will kill a moth that simply lands long enough to lay eggs.

I've never used a horticultural oil (the active ingredient in this stuff is mineral oil) but I've heard it can kind of screw up trees and fruit. And I don't know if it will do anything to the adult moths.

I think the neem oil will have the same issues of not killing the moths on contact. Or to be able to get to the larvae in the center of the apple.

I have a couple of ideas of what to do. I read that mixing horticultural oil with spinosad can make the spinosad more effective. I don't know if it acts as a penetrant or just keeps the spinosad wet longer. So I was thinking of using half oil, half spinosad. Or maybe half oil, half pyrethrins.

The other option is to regularly spray BT. It won't prevent the injection of eggs by the moth. But if it can get into the penetration site it should kill the larvae before they become large enough to do significant damage. But that's a big "if".

I'd be grateful for people's thoughts.

P.S. I know there is a specifically tailored virus spray that can whack the larvae but this stuff is expensive and probably outside my price range.

 

[Chuck]

I have a pear tree that they like to visit. What I do is spray the tree with Neem once a week starting just before blooming and there after until fruit are about half size. I still lose a few pears and could probably save them if only I would spray until harvest but it becomes a major PITA while trying to grow a large vegetable garden at the same time. Something else I do is to hang a bright light over a bucket of soapy water. I do this mainly for June Bugs but I also kill a ton of codling moths too.

 

[DirtMechanic]

I have been learning how insects literally smell what they are bio-coded to eat. Perhaps someone has done some work on how the moth chooses its target and that info is in a white paper out on google somewhere. The first search term should probably be its proper name and after that the search becomes easier. Maybe there is a perfume disguise that would work like a garlic oil or thyme oil.

 

[Chuck]

I have been learning how insects literally smell what they are bio-coded to eat. Perhaps someone has done some work on how the moth chooses its target and that info is in a white paper out on google somewhere. The first search term should probably be its proper name and after that the search becomes easier. Maybe there is a perfume disguise that would work like a garlic oil or thyme oil.

They have already done that. There are different pheromone traps that sometimes work. Some are sexual, others not. The only way to control them is to smother the eggs with Neem or some other oil. The problem is that the egg laying season is protracted and thus just about impossible to get them all. Unless of course you do what they commercially do and spray them with a long lasting poison.

 

[DirtMechanic]

They have already done that. There are different pheromone traps that sometimes work. Some are sexual, others not. The only way to control them is to smother the eggs with Neem or some other oil. The problem is that the egg laying season is protracted and thus just about impossible to get them all. Unless of course you do what they commercially do and spray them with a long lasting poison.

Then it seems a multiple layers of security type system is all one could do.

 

[Purrfluff]

They have already done that. There are different pheromone traps that sometimes work. Some are sexual, others not. The only way to control them is to smother the eggs with Neem or some other oil. The problem is that the egg laying season is protracted and thus just about impossible to get them all. Unless of course you do what they commercially do and spray them with a long lasting poison.

A really nasty poison is what I would like to avoid. If for no other reason than that the tree is tall and wide and all I have is a garden sprayer. I can't get to the top of the tree even with a long ladder. I figure I'll have to spray pretty much willy nilly to get most of the fruit and even then I will miss a lot of it. Which means I'll be spreading this crap all over the place. Including to nearby trees and plants that still have flowers. Frankly I'd rather deal with the damage from the moth than waste a bunch of beneficial insects with sevin.

It's not like I haven't managed for all these years with wormy apples. I was just thinking if there was a relatively benign way to cut down on the wormy apples it might be worth trying.

With horticultural oil do you just spray it once in hopes of getting the eggs? I don't know if the moths have hatched yet but if they have I would figure the oil wouldn't do much good. Will it actually discourage the moths?

And what about mixing the oil with something else? The downside of the organic pesticides I have is that they won't linger for very long. I read that pyrethrins can also act as an insect repellent but I don't know how strong that is. And pyrethrins are kind of expensive. The cheapest option is probably BT. I could spray that every four or five days without breaking the bank. But spinosad and pyrethrins will get spendy fast if I have to spray every three or four days.

 

[Purrfluff]

An update in mid June....

I have been aggressively thinning the apples that touch and I have been spraying spinosad, pyrethrins, neem oil, BT, and all seasons horticultural oil (i.e. mineral oil). Obviously not all at the same time. So far the apples look pretty pristine. But I never really checked before to see when the codling moths attack. So it may that they are about to go to town and haven't gotten around to it yet. I think the moths lay their eggs around June so I am hoping I won't have to spray after mid July. I'm not concerned about the human toxicity of the stuff I have used. It breaks down rapidly in sunlight and I would rinse the apples regardless. But spraying often is getting old and there are apples far in and up high that I simply cannot reach.

 

[DirtMechanic]

I am wondering about these coatings. A mineral oil improved to last longer. Silicone additive perhaps? Parrafin wax is also formed from refining crude oil and as a similar cast away from the process I wonder if it shares the ability to breathe gasses like mineral oil does oxygen.

 

[Purrfluff]

I am wondering about these coatings. A mineral oil improved to last longer. Silicone additive perhaps? Parrafin wax is also formed from refining crude oil and as a similar cast away from the process I wonder if it shares the ability to breathe gasses like mineral oil does oxygen.

That's an interesting idea. I know that there is such a thing as paraffin oil. I've used it as a lubricant during wood finishing. I think it's a little heavier than mineral oil. I do know that mineral oil is completely food safe (in fact you drink it as a laxative and buy it at the drug store). As such it is used as a semi-protective finish on wooden cuttinb boards. I don't know if paraffin oil is equally food safe. Nor that it would matter for insecticidal purposes.

I assume the mineral oil in the horticultural spray is diluted with something to make it easier to spray and to get it to mix with the water.