Which of the following describes a biological control method for weeds?

The correct answer utilizes natural mechanisms for managing weed populations. Biological control methods involve the use of natural predators, parasites, or pathogens to suppress weed growth. This method aims to harness ecological interactions to manage weeds sustainably, thereby reducing reliance on synthetic chemicals and promoting biodiversity.

For example, specific insects, fungi, or bacteria may be introduced to target particular weed species, allowing for control over their spread without the negative environmental impacts associated with chemical herbicides. Such methods can lead to long-term management of weed populations, contributing to a healthier ecosystem.

The other choices pertain to different strategies: synthetic herbicides involve chemical applications that can negatively affect non-target species and soil health, increasing irrigation affects plant growth conditions but does not specifically target weeds, and conducting soil tests is important for understanding soil health and nutrient content but does not directly address weed management.