What method applies pesticide to the lower portion of a plant's stem or trunk?

The method that applies pesticide to the lower portion of a plant's stem or trunk is a basal spray. This technique involves applying the pesticide directly onto the lower part of the plant, typically at the base of the stem or in the area of the trunk where it meets the soil. Basal sprays are particularly effective for controlling pests or diseases that affect the lower parts of the plant or for treating specific problems such as unwanted woody plants or pests that reside near the ground level.

This method is useful because it allows the pesticide to be absorbed into the plant tissue from the base upward. This targeted application minimizes pesticide use by concentrating on the areas where pests are likely to proliferate, reducing the likelihood of affecting non-target organisms or the environment.

Other methods, such as bark spray or foliar sprays, involve different applications. Bark sprays target the outer bark area, while foliar sprays are intended for treating the leaves of the plant. Soil injection involves placing pesticides directly into the soil rather than applying them to the plant's stem or trunk, making them less relevant to this specific question.