What are BTI granules primarily used for?

BTI granules, short for Bacillus thuringiensis israelensis, are specifically designed to target and control the larval stages of certain mosquito species, particularly those that breed in standing water. When BTI is applied, it works by disrupting the digestive system of mosquito larvae that consume it, leading to their death.

The option indicating the elimination of breeding sites of Aedes vexans is accurate because Aedes vexans is a species of mosquito known for breeding in areas with standing water. Applying BTI granules in these environments helps to reduce the population of this mosquito by preventing the larvae from developing into adults.

In contrast, other options do not align with the primary use of BTI. Controlling adult mosquito populations is not the function of BTI, as it specifically targets larvae. Deterring pest insects generally refers to approaches that repel insects rather than kill them. Finally, enhancing the growth of beneficial insects contradicts the purpose of BTI granules, which are aimed at limiting the populations of specific pests rather than promoting the growth of other insects. Thus, understanding the targeted action of BTI granules highlights their effectiveness in mosquito larval control, particularly for species like Aedes vexans.