Watering and delivering insecticide at the same time?

[Ashby Chadburn]

I have reviewed a lot of the threads about insecticides and I have decided to give Merit a try. My understanding is that it is sprayed on the insects, but also should be delivered to the planting medium to be taken up by the plant as a systemic. I would like to use my Dosatron to deliver the Merit when I water with no fertilizer. What amount of Merit do I add to plain water in the concentrate bucket to achieve the correct dosage? Do I measure it with by dissolved salt meter to achieve a certain parts per million? Can any chemists give me some help? It's my last hope to get rid of these mealy bugs. Thanks for any help.

[Ray]

How much you use depends upon which specific Merit formulation you have (i.e., concentration of the active ingredient), and the proportioning ratio of your dosing pump. As you have not provided those, nobody can give you the exact answer you're looking for. However...

I have a bottle of the 75% Wettable Powder (75% imidicloprid), and the instructions for use on flowers and foliage crops is 0.1 tsp/gallon.

That means you'd need 0.1/(100%/75%) = 0.075 tsp/gal of 100% stuff - making that our "baseline" for imidicloprid.

If you get a product that's 5%, for example, then you'd need 0.075/0.05=1.5 teaspoons per gallon in the final dilution.

So now you simply take the proportioning ratio and multiply it by that result. If your proportioner is set at one ounce per gallon (1:128) for example, that 5% stuff would need to be at 128 * 0.075/0.05 = 192 teaspoons per gallon, which is one quart.

So if you want a "universal" formula, and don't want to do any decimal conversions:

7.5/percent on label - teaspoons per gallon of final spray, and

(7.5 x proportioner ratio)/percent on the label = teaspoons per gallon in the concentrate.

[Discus]

This probably goes without saying, but make sure you wear adequate PPE when doing this, and remember, your dosing unit and hoses etc. will be moderately contaminated with pesticide until adequately rinsed.

[Ashby Chadburn]

Thank you Ray. I knew you would know how to measure what I need. So to review. If I use the 75WP and my Dosatron is set at 1:200, then it would be 7.5X200/75=20 teaspoons per gallon in the concentrate. I appreciate your help and patients with use challenged growers.