What is a key feature of systemic pesticides?

Systemic pesticides are specifically designed to be absorbed by plants and then translocated through their vascular systems, which includes both the xylem and phloem. This movement allows the pesticide to affect not only the parts of the plant where it was applied but also other areas, making it effective against pests that might not be directly in contact with the application site. This ability to spread throughout the entire plant is particularly beneficial for controlling pests that feed on various plant tissues, such as sap-sucking insects that affect the inner tissues or roots.

Other options do not accurately reflect the characteristics of systemic pesticides. For instance, saying that they only act on the surface of the plant would apply to contact pesticides instead. The notion that they do not need watering for activation overlooks the fact that many systemic pesticides require some form of irrigation or rainfall to help facilitate uptake by the plant roots. Lastly, while systemic pesticides can be applied to a wide range of plants, the effectiveness and safety can vary based on the specific plant species, making the statement about applicability to all types of plants too broad.