Which of the following is an example of a non-chemical control method?

The correct answer is the use of pest-resistant crop varieties as an example of a non-chemical control method. Non-chemical control methods refer to practices that manage pest populations without the use of conventional pesticides. This approach often relies on biological, cultural, or physical practices that enhance plant health or deter pests naturally, rather than relying on chemical means.

Planting pest-resistant crop varieties is effective because these crops have been bred or selected for traits that make them less susceptible to specific pests and diseases. This method can significantly reduce pest populations and crop damage without the need for chemical intervention, promoting a more sustainable form of agriculture.

In contrast, the other choices involve the application of chemical substances to control pests. Insecticides, fungicides, and herbicides are all classified as chemical control methods. They work by directly killing or inhibiting the growth of unwanted organisms, which can lead to potential issues such as pesticide resistance and negative environmental impacts. Thus, the non-chemical method of planting pest-resistant varieties stands out as a sustainable alternative in pest management strategies.