Rav Avraham Dantzig (author of the Chayei Adam) in his Sefer Sha'arei Tzedek, says that the prohibition only applies to exporting large quantities of produce from Eretz Yisrael - as opposed to exporting Shemitah produce where the prohibition applies to any amount. What exactly "large quantities" means is unclear. It probably refers to a noticeable portion of the entire crop; some measurable percentage.

Regarding wine specifically there may be no issue. The Gemara and the Rambam say that the prohibition applies to things that are "Chayei Nefesh" (critical commodities). The examples that the Gemara gives are wine, oil, and flour. In the times of Chazal these were the staples of the local diet. I don't know if today wine would be considered Chayei Nefesh. Therefore it is not clear that the prohibition would apply to wine today.

I asked your question to Rav Moshe Sternbuch. He said that the prohibition does not apply to produce that was grown for export, and for this reason the Hashgachah organizations aren't sticklers on this matter (with the noticable exeption of the Satmar Rav and many Satmar Chasidim who are Makpid).

Chanukah Sameach,

Yonasan Sigler

This is not a Psak Halachah