The beetle used as a biocontrol agent for aphids and mosquitoes is:

Ladybird

The correct answer is Option (3) -Ladybird

In agriculture, there is a method of controlling pests that relies on natural predation rather than introduced chemicals.

The very familiar beetle with red and black markings – the Ladybird, and Dragonflies are useful to get rid of aphids and mosquitoes. Ladybird beetles, also known as ladybugs or ladybirds, are beneficial insects that feed on aphids, which are pests that can damage plants. Ladybird beetles are often introduced into agricultural fields or gardens as a form of biological control to naturally reduce aphid populations. Similarly, dragonflies are natural predators of mosquitoes and their larvae. Dragonflies are known for their voracious appetite for mosquitoes and are commonly used as a biocontrol agent to control mosquito populations in certain areas.