Coincidence? Or retaliation, and a warning to Karzai not to get too frisky (as PBD puts it, "the horse's head")? Decide for yourself. But recall that the "Northern Alliance" that we — quite properly — backed against the Taliban was basically a trade group of heroin traffickers.
One question not asked in the New York Times story is how much it matters to the drug problem in the U.S. whether the Afghan government cracks down on poppy-growing or not. As someone who has spent a quarter of a century studying drug abuse and its control, I can assure you that the answer to that unasked question is: "Damned little."
Raw opium isn't scarce, relative either to heroin demand or to the capacity of the world's heroin-trafficking networks. The cost of the opium that goes into making a $10 bag of heroin is about a dime.
Moreover, the products made from Afghan poppies stay almost entirely in the Old World; our heroin comes mostly from Colombia (mostly via Mexico) and Southeast Asia (mostly via Hong Kong).
We should keep our eye on the main chance. If post-Taliban Afghanistan works, that's good for us. If it breaks down, that's bad for us.
So, from a U.S. perspective, the optimal amount of poppy eradication in Afghanistan is whatever amount is most likely to lead to good outcomes in Afghanistan.