Taiwan threatened to take China to the World Trade Organization on Sunday after Beijing said it would suspend sugar apple and wax apple imports from the island on pest concerns, in the latest spat between the two over fruit. Relations between Taipei and Beijing, which claims democratically ruled Taiwan as its own territory, are at their lowest in decades, with China increasing political and military pressure to get the island to accept its sovereignty. China's customs administration said it had repeatedly detected pests called "Planococcus minor" in sugar apples, also known as sweetsops or custard apples, and wax apples from…