Bacterial thuringiensis is used to control which of the following?

Insect pests.

Bacterial thuringiensis (Bt) is primarily used to control insect pests.

Bacillus thuringiensis (Bt) is a bacterium that produces proteins called crystal toxins or delta-endotoxins. These toxins are toxic to a specific group of insect pests and can be used as biological control agents to manage their populations.

When Bt is applied to crops or other environments where insect pests are present, the insects ingest the Bt toxins. The toxins target specific receptors in the gut of susceptible insects, leading to the breakdown of the gut lining and causing the insect to stop feeding, eventually leading to its death. Bt is highly specific to certain insect orders and is generally harmless to non-target organisms, including humans, pets, and beneficial insects.

Bt-based insecticides have been developed and used extensively in agriculture to control a wide range of insect pests, including caterpillars, beetles, mosquitoes, and flies. They are employed in various crops, such as corn, cotton, vegetables, and fruits, to reduce pest damage and minimize the need for conventional insecticide use.

While Bt is primarily used for insect pest control, it does not have direct effectiveness against fungal pathogens, bacterial pathogens, or nematodes. Its action is specifically targeted towards insects susceptible to Bt toxins.