BT Thuricide questions.

[FountainMan]

My previous thread focused primarily on the China Mark Moth Larvae pest. I have some questions regarding the use of the Thuricide BT. I poured a little bit in the skimmer to disperse the stuff throughout the water. I also wound up removing the last of the infested lily pads. I read up on BT applications and learned the stuff is usually sprayed on infested foliage rather than mixed into the pond water but haven't read anything discouraging what I did. I figured the larvae would all eventually ingest the live BTK bacteria in the pond water and become infected and die. I'm wondering if the live bacteria would colonize in the pond to continue to protect against future caterpillar attacks or if I'd need to reapply it? Also I learned the BT is temperature and light sensitive. Right now here in North Texas we're experiencing an intense heatwave (106-111°F) and the pond water is bathwater warm from the heat. Our patio is north facing though we get just enough sunlight to keep sun loving plants healthy. Will this be a problem for the BTK? I'm anxious to see these caterpillars die and for my plants to make a rebound but I'm concerned that the environment might be working against me.

Any advice?

 

[Mmathis]

Good questions, but as I think I already said, I never had to use it (I was doing a pond re-hab at the time of my infestation, and all of my lilies were in temporary tubs. I ended up just picking the larvae off the plants and tossing them into the tub with the fish.....so that manual method worked and I never had the problem again, once the lilies went back into the pond.). All I really recall during my research was that you spray or sprinkle it directly on or around the leaves, and I recall something about doing it at dusk — maybe that’s in reference to light and heat. But as far as effectiveness being mixed with the larger volume of water.....I would suspect that it would be too dilute to do any good. I think it’s more a topical treatment and not effective in solution. IOW, it’s meant to target specific critters, and those are going to be found on the leaf surface rather than in the water. I don’t think it would harm anything, just not be or be as effective. Now, I admit that I could be 100% wrong, but that’s just my understanding from my reading of 3 or 4 years ago. Hope it helps! Does it give any directions that say “Do not use if the temperature is above.....”?

 

[FountainMan]

I'm assuming it's too early to tell but it looks like the Thuricide might be working already. I mean most of the caterpillars were probably removed when I removed the dead foliage but I managed to find a cocoon floating in the skimmer and I opened it up and sure enough the inhabitant was dead.

Here's the caterpillar's mugshot. Ugly looking con isn't it. Lol!