Abstract: A post directed crop spraying apparatus and related method, comprises a pair of opposed substantially vertically extending hood members coupled to a main mounting means. Spray nozzle means are coupled to the main mounting means and disposed between the hood members for spraying liquid material toward the ground between and under the hood members to cross row centers at the base of plants being sprayed. Knockdown bar means are coupled to the main mounting means and extend substantially transversely between the hood members for contacting and for pushing down on weeds during operation of the apparatus. The knockdown bar means are located sufficiently close to the nozzle means to permit the nozzle means to spray liquid material onto the weeds from the bases to the tips thereof and to permit liquid material to be applied in a substantially uniform pattern to the soil around the plant bases.

Abstract: A control circuit for tracking of a heat radiation source which functions to maintain heat collection structure in optimum alignment with the source thereby to enable maximum efficiency of heat collection; the control circuit includes a threshold circuit for sensing ambient light level to provide enablement control to A-C power circuitry which energizes the heat collector orienting drive system, and the threshold circuit also functions to automatically invert the heat collector to a protected position upon detection of insufficient threshold voltage; and, the circuit further comprises a tracking section energized by a radiation sensor to cause intermittent energization of the drive system to further enable intermittent bi-directional tracking movement of the heat collector, such tracking circuitry being enabled by detection of sufficient threshold voltage.