I keep several large planters full of petunias on my patio because they’re easy to care for and usually require little attention; just regular watering and removal of the wilted and dried out flowers.  When I started to notice holes in the blooms and less frequent flowering, I did a little research and discovered what was causing the problem – budworm caterpillars. 

When my petunias had totally stopped blooming (because the caterpillars were eating the buds), I decided to take lethal action.  I wanted something that would kill the caterpillars but not harm other types of wildlife and pets.  After reading about insecticides, I decided to use Bonide Thuricide BT Killer because it’s environmentally friendly, won’t harm pets, humans, or beneficial bugs and critters.

What is Bonide Thuricide BT Killer?

Bonide Thuricide BT Killer is a concentrated liquid pesticide that specifically targets certain flower and leaf eating caterpillars.  The active ingredient is Bacillus Thuringiensis (BT), which is a bacterium that is lethal to susceptible caterpillars.  After the caterpillars ingest the bacteria, their digestive system shuts down, they stop eating, and die from starvation within a few days.

Bonide Thuricide BT Killer is a biological (naturally occurring) pesticide that does not contain artificial chemicals. However, the product label does list first-aid treatment (for humans) if it gets in the eyes, on to skin, or is ingested.

The white plastic bottle of Bonide Thuricide BT Killer contains 16 ounces (1 pint) of concentrated BT.  The malodorous liquid is green with a cream-like consistency. The accompanying directions explain how to use it depending on the crop and pest.
 
Bonide Thuricide BT Killer will not kill caterpillar eggs, it’s only effective on worms that are actively eating.

Using Bonide Thuricide BT Killer

After identifying the pest that was eating my petunias, I chose Bonide Thuricide BT Killer because it’s nontoxic to pets.  My two indoor cats lounge around the patio so I didn’t want to use any harsh chemicals that could affect their health. 

The directions that come with the Bonide Thuricide BT Killer don’t specifically mention how to treat petunia plants, so I went along with their recommendation for trees, shrubs, and flowering plants – 4 teaspoons per gallon of water.  The information booklet also mentions how to treat other types of plants and crops; tomato, squash, etc.

Using a plastic watering jug (that also has a spray nozzle) I poured approximately 4 teaspoons of the stinky Thuricide into the jug and then added water.  After shaking the mixture, I then proceeded to spray it directly onto the petunia plants and leaves.  I did this in the evening (dusk) because the caterpillars are most active at this time, and the sun wouldn’t quickly dry-out the mixture on the plants.  The caterpillars need to ingest (drink) the mixture for it to work.  It doesn’t kill them on contact.

After thoroughly saturating the petunias I still had quite a bit of the mixture left over.  Since the directions state that the mixture shouldn’t be stored, I just poured the remaining into the plant’s dirt. 

The Results

After using the Bonide Thuricide BT Killer I noticed a significant reduction in the amount of holes in my petunias.  And the petunia plants that had totally stopped blooming (because of the infestation) started to flower again. 

Since the treatment doesn’t affect the eggs of the caterpillar (which may have hatched), I decided to give the plants a second treatment a week later.  So far, so good - I haven’t seen any large juicy caterpillars on my petunias and there are no holes in the flowers.  I’ll continue using Bonide Thuricide BT Killer on a regular basis.

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