The cycle is ongoing: We develop ways to control pests and weeds, they adapt accordingly. Resistance to pesticides is an urgent concern for agriculture, and experts are divided on the way forward. Some say chemicals are still the best solution. The EPA this fall approved “Enlist Duo,” a new combination of herbicides meant to fight chemical-resistant “super weeds.” But the NRDC and other groups filed suit to block it, citing risks to the environment and human health, and concerns that we are on a dangerous path toward increased chemical use. For this month’s Environmental Outlook, what’s at stake and what’s ahead in the race against pests and weeds.