37 and the clock input 38 of programmable digital delay timer 33 circuit 4 d flipflop clock input 37 divides the 1024 hz pulse train received from pulse train generator 34 into a 512 hz signal this signal is used by the counter not shown of binary counter 32 when it is desired to record a setpoint time delay to control the flow of exterminating fluid through apparatus 10 circuit 5 the setpoint time delay is set when the operator squeezes valve lever 23 of the apparatus 10 the action of the operator causes the normally open magnetic switch 26 to close when magnet 27 on valve lever 23 comes into proximity to the magnetic switch 26 on cross member 20 circuit 6 inverting debouncing circuit 35 with a one half second delay at the output of magnetic switch 26 opening senses the closed position of magnetic switch 24 and turns its output high circuit 8 d flipflop circuit 39 monitors the output of inverter 41 and power up reset circuit 36 circuit 9 the nor gate output 42 of circuit 9 turns high as its inputs from inverter 41 and power up reset circuit 36 are both low circuit 10 the high output of nor gate output 42 causes the output of inverter 43 to be low circuit 11 the low output of inverter 43 feeds into one input of nor gate 44 circuit 12 with this low input to nor gate 44 the 512 hz pulse train from d flipflop clock input 37 of circuit 4 is fed into the clock input 45 of binary counter 32 the counter not shown of binary counter 32 starts counting and continues to count until one half second after valve lever 23 to apparatus.