Here’s a thought… 
Does agriculture exist to serve the interests of commodity futures-traders?
or
Does trading in commodity-futures exist to serve farmers and agro-buyers?
It is generally accepted that they benefit each other.
A symbiotic mutually-beneficially relationship exists between the two -
the underlying economic-activity and the trading in its futures.
A forward contract is an agreement between two parties to exchange at a fixed future date a given quantity of a commodity for a specific price defined when the contract is finalized. The fixed price is also called forward price.
Such forward contracts began as a way of reducing pricing risk in food and agricultural product markets. By agreeing in advance on a price for a future delivery, farmers were able protect their output against a possible fall of market prices and in contrast buyers were able to protect themselves against a possible rise of market prices.
Forward contracts, for example, were used for rice in seventeenth century Japan.
[ Source ]
In an ideal scenario the participants in the futures-market
- enable proper price-discovery
- enable stable / guaranteed pricing
- provide additional liquidity
The futures-market participants may be able to extract some profit in exchange for the above.
If the futures-market becomes extremely volatile, or begins to behave erratically,
i.e. begins to speculate instead of proper price-discovery,
is the futures-market serving any purpose to the underlying economic activity anymore?
In such a scenario, does it make sense to temporarily pause the futures-trading? 
According to this article, regulating the futures market to control the price of a commodity, is a fool’s errand.
The speculation / erractic behavior of a futures market is generally NOT a root-cause,
rather a symptom of the uncertainty that exists around the price of the commodity during the period.
Thus, temporarily banning futures-trading will NOT be able to avoid price fluctuations due to the underlying uncertainty. However, such a ban can ensure that the futures-market does NOT further contribute to the fluctuations/uncertainty.
Also, here’s a recent related discussion on Free-Market vs. Regulation.