Abstract: An agricultural implement, such as a cultivator or harrow has fluid sprayers mounted on a boom extending across the implement's width. Adjacent each sprayer, a monitoring device is positioned to signal if the sprayers malfunction. The monitoring device includes a dielectric housing having an upper holder for a wire probe and a detachable lower cover that is hollow and has an open lower end. The cover has an inner chamber and an external skirt. The probe extends through the chamber and out of the lower end to a location near the outer edge of the spraying pattern. It is preferred that the lower portion of the probe be curved and extend in the direction of the fluid being sprayed. Each probe communicates to a respective light mounted on a control box located within the view or supervision of the implement operator so that any malfunction of a sprayer is immediately sensed.