((a)) Whenever the Secretary finds that a plan or any provision thereof obstructs or does not tend to effectuate the declared policy of this chapter, the Secretary shall terminate or suspend the operation of the plan or provision.

((b)) The Secretary may conduct a referendum at any time, and shall hold a referendum on request of the Board or at least 10 percent of the combined total of the watermelon producers, handlers, and importers eligible to vote in a referendum, to determine if watermelon producers, handlers, and importers favor the termination or suspension of the plan. The Secretary shall terminate or suspend the plan at the end of the marketing year whenever the Secretary determines that the termination or suspension is favored by a majority of those voting in the referendum, and who produce, handle, or import more than 50 per cent of the combined total of the volume of the watermelons produced by the producers, handled by the handlers, or imported by the importers voting in the referendum.