is petroleum product either applied directly on plants as a pesticide or used as an adjuvant to enhance the effectiveness of a pesticide. A good agricultural oil should have low volatility for longer adherence to leaf surfaces, low surface tension for better surface coverage and easier atomization, and low water solubility to resist rain washoff. There are two basic types of agricultural oil: orchard spray oil and crop oil. The former should have low phytotoxicity (harmfulness to plants); this is accomplished by controlling molecular weight within optimal limits and by maximizing unsulfonated residue content. A crop oil is lower in quality and commonly used as an adjuvant in herbicide spray formulations.