Cecilia from Howell, Nj writes
I have been using Bonide house plant granules (0.22% imidacloprid) in the soil of 2 large jade trees and other smaller pots in my sunroom to combat mealy bugs systemically. The Bonide label specifies how much product to use based on the diameter of each pot. Now that summer is here I can take the plants outside to spray them. As a foliar spray specifically for houseplants, the Dominion 2L label recommends 45ml/100gal which works out to be about 2.5ml or ½ teaspoon per gallon. That’s easy enough as a foliar spray but I want to drench the soil in each pot so the plants can continue to take up the imidacloprid through their roots. Since I have Dominion 2L, I’d prefer to use a liquid solution instead of using the Bonide granules in each pot. Question: Given that the label states Dominion 2L can be used as a foliar spray for indoor plants, do you see any problem with using it in the potting soil of indoor plants as well (like the Bonide granules)? The Dominion 2L label recommends a soil drench of 3ml-6ml per inch of tree trunk diameter mixed with enough water to deliver that amount of imidacloprid evenly. The label is referring to outdoor use but I’m wondering if that translates to indoor trees as well. For example, my indoor jade trees have trunks with 6” circumferences (1.91” diameters). To me, that means each jade tree that size would need 6ml-11ml of imidacloprid in their potting soil. I’d probably use 1½ teaspoons (7½ ml) Dominion 2L in a gallon of water for each jade. Question: Do you agree? But, what solution would I use for my smaller potted plans that don’t necessarily have trunks to measure? I don’t see anything on the label about a potting soil drench for indoor plants; the soil drench solutions for outdoor perimeter use (termites, ants etc.) are way too potent I believe. Question: Do you think it would be effective to use the foliar spray solution (1/2 teaspoon/gallon) on the leaves and then drench the soil with the same? I’m not convinced of this idea. It seems that the amount of water the product is delivered in is not as important as the specific amount of imidacloprid delivered per size of plant (or pot). Thanks for your help when you have time.
You are pretty much spot on, on most of your calculations. There shouldnt be any problem using the Dominion 2L in the soil of the potted plants in a drench method. The amount you calculated for the jade tree is correct for the drenching of its roots. For plants that do not have a trunk circumferance large enough to really matter, treat the plant as a shrub and go by heighth to determine the correct amount of solution to use per foot of shrub height. The .6 ounces is foliar dilution only so it wouldnt be the best option to just use automatically if the plant is smaller and calls for less. Also, you are absolutely CORRECT in that the water acts as the carrier of the product so making sure the amount per plant is right is the biggest key. Please let us know if you have any other questions!
Answer last updated on: 06/30/2013