Insects help in pest control examples:
The Big Eyed bug is a predator and are found in many habitats, including fields, gardens, and turf grass. Big-eyed bugs are considered an important predator in many agricultural systems and feed on mites, insect eggs, and small insects such as pink bollworm, cabbage loopers and whiteflies
The Damsel bugs are considered helpful species in agriculture because of their predation on many types of crop pests, such as cabbage worms, aphids, and lygus bugs.
The Mealybug ladybird has been used as a biological control agent against Mealybugs and other Scale insects (small insects, most are considered as pests). Unlike most brightly coloured ladybirds it is predominantly brown and has no spots. It has the common name Mealy bug destroyer. It was introduced into California in 1891 by Albert Koebele to control the citrus mealybug. It has also been introduced to New Zealand for biocontrol.
Soldier beetles are highly desired by gardeners as biological control agents of a number of pest insects. They consume grasshopper eggs, aphids, caterpillars and other soft bodied insects, most of which are pests. The adults are especially important predators of aphids(also known as plant lice as they eat plants). They supplement their diet with nectar and pollen and can be minor pollinators
Hoverflies: species of hoverfly larvae prey upon pest insects, including aphids and the leafhoppers which spread some diseases like curly top. Therefore they are seen in biocontrol as a natural means of reducing the levels of pests. Aphid-feeding hoverflies are being recognized as important natural enemies of pests, and potential agents for use in biological control because aphids alone cause tens of millions of dollars of damage to crops worldwide every year.
Trichogramma wasps are some of the most widely-studied agents of biological contro. Trichogramma wasps are tiny insects, measuring 1 millimeter in length or less. They parasitize the eggs of many types of agricultural pest insects that means the female wasps inject their own eggs into the egg of the pest, and her larvae consume the embryo and other contents of the egg
They are easy to rear and release in fields suffering from pest outbreaks. The wasps are currently used to control at least 28 species of insect pest, including the cotton bollworm, codling moth, and corn borer.
Another way in which insects help humans is by pollination. Without insects pollinating plants we would not be able to get all the fruits and veges. One of the most important pollinators is the bee. Today pollination management seeks to protect and enhance present pollinators.This involves the culture and addition of pollinators for commertial orchards. The largest managed pollination event in the world is in Californian almond orchards, where nearly half (about one million hives) of the US honey bees are trucked to the almond orchards each spring. New York's apple crop requires about 30,000 bee hives; Maine's blueberry crop uses about 50,000 hives each year.
Bees are also brought to commercial plantings of cucumbers, squash, melons, strawberries, and many other crops. Honey bees are not the only managed pollinators: a few other species of bees are also raised as pollinators. The alfalfa leafcutter bee is an important pollinator for alfalfa seed in western United States and Canada. Bumblebees are increasingly raised and used extensively for greenhouse tomatoes and other crops.
Crops such as apples, almonds or coffee grown in the vicinity of a forest or wild grasslands have the native pollinators of the forest or wild grasslands nearby. This can can improve the crops yield by about 20%. Also pollination produces some $40 billion worth of products annually in the United States alone
Pollination of food crops has become an environmental issue. This is because of the decline of pollinator populations due to pesticide misuse and overuse, new diseases and parasites of bees, decline of beekeeping, suburban development, removal of hedges and other habitat from farms, and public paranoia about bees. Observed losses would have significant economic impacts and could even lead to shortages of food if there are no pollinators to pollinate the flowers.
(LOL I know its wayy too much info but I hope it helps :D)