There are a lot of insects that are of benefit to farmers. These insects feed on other insects that damage crops. This group of insects are called predators. A good example of this is the ladybird beetle or Ladybug. Ladybird beetles come in different colours and they usually have black spots on their wings.
Both adult and larvae feed on crop pests such as aphids, blackflies and greenflies. One lady bird beetle can eat nearly 5000 aphids in its life time. Thus, making them great biological control agents.
A farmer who is interested in the balance of nature should create good living conditions for predators so that they can carry out their task of keeping crop damaging pests in check. To conserve predators avoid indiscriminate use of broad-spectrum insecticides and plant flower hedges in your farms.