According to an article at DigiTimes, the Taiwanese media manufacturer Postech has decided to stop production of DVD+R/-R discs.
Postech, a second-tier producer of optical discs in Taiwan, has decided to stop production of DVD+R/-R discs in the first half of this year and shift to other products, according to industry sources. Postech declined to comment on the report.

Postech made the decision because its 8x DVD+R/-R discs are not competitive and the company has had difficulties upgrading to production of 16x DVD+R/-R or 8x DVD+R/-R DL (single-sided double-layer) discs, the sources pointed out.
I don't think many will be saddened by this as Postech had a very small market share, especially here in North America. If you'd like to read more, the entire article can be found here.