You should be able to find and identify a number of different bugs on or around crops.
Look under the leaves!
Look near the flowers!
Look in the soil!
Look in your compost!
You should be able to determine if a bug is helpful or not helpful on the farm.
For example, bees and butterflies transport pollen from flower to flower which allows plants to reproduce and produce fruit. Bees and butterflies are very helpful on the farm!
Another example, aphids use their long tongue (or proboscis) to suck the juices from stems, leaves and fruits of a plant causing them to die or rot. Aphids are NOT helpful on the farm! (We call them pests!)
You should be able to properly remove any pests found on crops.