Which of the following adjuvants is used to improve pesticide adhesion to plant surfaces?

The correct choice is Stickers, which are specifically designed to enhance the adhesion of pesticides to plant surfaces. Their primary function is to create a stronger bond between the pesticide formulation and the leaf or stem, ensuring that the active ingredients remain in contact with the plant for a longer period. This is particularly important for certain applications where moisture, rain, or other environmental factors could wash off the pesticide. By improving adhesion, stickers help to maximize the effectiveness of the pesticide treatment.

Drift retardants, while important for minimizing pesticide drift during application, do not contribute to adhesion on plant surfaces. Surfactants reduce surface tension and can help with spreading and penetration, but they do not specifically target adhesion. Buffers are used to maintain the pH of a pesticide solution but do not influence how well the pesticide sticks to plant surfaces. Thus, stickers are the adjuvants specifically aimed at improving adhesion, making them the correct choice for this question.