Biological control of insect pests of crops can best be carried out through

Biological control of insect pests involves the use of living organisms to manage the population of pests in crops. Out of the given options, the best way to carry out biological control of insect pests of crops is through the use of parasites and predators. Parasites and predators are natural enemies of insects that feed on or live inside them, ultimately leading to their death or reduced reproduction. Introducing these natural enemies into crop fields can help reduce the population of pests without using harmful chemicals, thus minimizing the environmental impact and preserving beneficial insects. Crop rotation involves alternating crops in a particular field to avoid the buildup of pests that are specific to a particular crop. Farm sanitation entails keeping the farm clean and free of debris to prevent the breeding of pests. These methods can help reduce pest populations but are not as effective as the use of natural enemies. Soil fumigation involves the use of chemicals to kill pests in the soil. This method is effective but also harmful to the environment and other beneficial organisms in the soil. The use of resistant varieties involves planting crops that are naturally resistant to certain pests. However, this method may not be effective against all pests and can lead to the emergence of new resistant strains of pests.