The shutdown of Nigeria’s land borders to tackle rampant food smuggling and encourage an agricultural revival in Africa’s top oil producer is having an unintended side effect: higher inflation. A spike in food prices saw the annual consumer-inflation rate rise to 11.2% in September, after falling to a 3 1/2-year low in the preceding month, the National Bureau of Statistics. Food-price growth accelerated for the first time in four months, rising 1.3% from August. In late August, Nigerian President Muhammadu Buhari ordered the partial closing of its boundary with Benin to curb smuggling of rice, a staple. With a population barely 5% of Nigeria’s, Benin has turned into the world’s No. 2 exporter of rice while Nigeria is expected to be the biggest buyer of the grain this year. The policy has hurt food sellers in the capital, Abuja, who say Nigerians prefer imported food items because they’re more affordable. Prices of imported products such as rice, palm oil and frozen chicken have gone up by more than 50%, they say.