Kemach Yoshon

The Torah (VaYikra 23:14) forbids eating grain products (made of wheat, barley, oats, spelt, or rye) that took root after the 16th of Nissan, when the Omer sacrifice was brought, until the 16th of Nissan of the following year. Until that time, the grain is known as "Chodosh", "new"; after that time, it is known as "Yoshon", "old". All grain sold during the spring and the summer can be assumed to be Yoshon, since it is likely that it was planted before the 16th of Nissan; but the possibility of Chodosh arises in the fall and winter.
Most Rabbis rule that this prohibition applies in both Israel and the Diaspora. Some say that it applies in the Diaspora only to grain grown on Jewish-owned land; but many great Rabbis have ruled that we should be stringent if possible, even for grain grown on non-Jewish land in the Diaspora,
For many years Chodosh was not a problem in America because large surpluses of wheat were stored every year, and only the older wheat was sold to millers; thus virtually all wheat available on the market was Yoshon. In recent years, however, new wheat has been reaching the market.
Many still rely on those Rabbis who permit Chodosh in the Diaspora; but all agree that Chodosh in Israel is prohibited. However, one can assume that Israeli products that have a reliable Kosher certification are Yoshon.