Timing of any type of topical spray - organic or not - is critical. The leafminers are the larval stage of a flying insect and you need to treat when the adults are present and laying eggs.

I don't care to remark on the "goodness" or "badness" of any chemical pesticide. They simply are not options I care to pursue. But there are effective organic controls - Neem oil is one - that can help with this problem, provided they are applied with the understanding of the lifecycle of the target organism you are attempting to control. Pheremone traps are also available.

And FWIW, unless they are completely defoliating your trees, leafminers tend to be more cosmetic than actually harmful, specially with mature trees that can more easily withstand the predation. If present in very large populations, there is something seriously out of balance in your garden.

Here is a link that might be useful: citrus leafminers

Bill, you have other options than one of the worst systemics available! I understand the seriousness of citrus leaf miners, and their wicked ability to have numerous generations in a year. In your location, the life cycle may be continuous throughout much of the year! With a new batch every three weeks or so, it's easy to see why you feel like you're losing the battle.

Neem, as mentioned above, has shown great promise in citrus. You should also look into products containing Spinosad (might even be considered organic), too. Expensive, but highly effective. Many manufacturers are now making their own version. I highly recommend it.

You need to have a clear understanding of when the adults are active (what time of day), as well as other facts about these little pests.

I suggest that you contact your area extension office, which will have plenty of information regarding this serious pest of citrus. Be sure to mention that you are an organic gardener. Don't let them convince you to go with the Imidacloprid (Bayer's Systemic). It's suspected of doing damage to bees and other pollinators (toxins in nectar and pollen).

Bill, I think you got some good advice from the above posters.

However my concern is that you may be using the product against it's label instructions and when you do that, all bets are off.

Even if the label says it is 'food safe' that doesn't mean it really is. However when you use a product on food items that the label doesn't say it is safe for you are asking for serious problems.

The label for your product says it can be used on: apple, Crabapple, Loquat, Mayhew, Oriental Pear, Pear, Pecan and Quince.

If you are using it on citrus trees, then you are using it on trees not included on the label(according to my reading).

Please read the label and don't use products on plants not included in the list of 'safe' plants to use the product on. If you want to take your own risks that is your business, of course, but never offer the produce to anyone else who isn't aware you used a pesticide not labeled as safe to use the product on.

For any systemic pesticide to work it needs to be applied to the soil, work its way down to the soil killing off at least parts of the Soil Food Web on its way, and then be taken up by the plants roots where it will be spread throughout the trees system, even into the fruit.
Yellow sticky traps have been shown to be effective in controlling the adults that lay the eggs the become the Citrus Leaf Miner and attracting the wasps that lay eggs in the larva is also somewhat effective.

Thanks to you all for the information.

Kimmsr, I have not considered traps or read much about the use of traps. I'm going to investigate more and possibly try this.

Or I may try the traps in combination with Neem, if they can be used together.

Bill

I gave the link to the wrong product. The correct link is below. it's for citrus. I've been doing more research, especially on oils. The trouble, as far as I can tell, is that most oils should not be applied when temperatures and humidity are high--and that's about half the year in central Florida. It's also the half of the year when leafminers are most active. I still haven't found a lot of information on the use of traps. They seem to be used more for monitoring. I will continue research, both on traps and on oils that can be used at high temps and humidity without damaging plants. Does anyone know of any?

Bill

Here is a link that might be useful: the product

By "oils" I mean also botanical oils such as neem.

Same active ingredient, manufactured for Restricted Use purposes. You didn't mention that you had your commercial pesticide applicator's license.