This 5-year study addresses how improved quality of agricultural extension may lead to more sustainable pest management. We studied 112 agricultural extension workers trained as plant doctors under the Plantwise program in China. They run 70 plant clinics in Beijing, Guangxi, and Sichuan provinces. We analysed 47,156 recommendations issued by these plant doctors to 13,051 different growers between 2012 and 2017, and this for 250 different plant health problems on 91 crops. We also interviewed growers who had taken queries to plant clinics. On average, 86% of plant doctors provided comprehensive integrated pest management recommendations to the growers, with a 16% improvement in comprehensiveness over years. This most often included advice of synthetic pesticides (66%) with its frequency not much changing with time. In contrast, as a likely result of Plantwise interventions and China’s pesticide reduction policies, recommendations for biological control increased from 2% to 42%, pest monitoring by 8%, and cultural control by 11%. Recommendations of  problematic plant protection agents as listed in the Montreal Protocol, Stockholm or Rotterdam convention, or as highly toxic under WHO’s toxicity classification were already rare in 2013 (1.9%) and nearly phased out by 2017 (0.2%). About 92% of growers implemented the advice, suggesting that agricultural extension services may contribute to changes in agricultural practices at scale. Further investment in such agricultural extension services may be warranted instead of phasing them out.