The use of streptomycin, oxytetracycline, copper-based products, and some fungicides is correlated with increased resistance among plant pathogens to such agents. Additionally, the recent rise in the incidence of environmental triazole fungicide-resistant Aspergillus fumigatus—the cause of aspergillosis in humans—has caused concern, especially in Europe.

Through horizontal gene transfer, genes can be exchanged among a variety of bacteria in the plant production environment, including phytopathogens, soil bacteria, and zoonotic bacteria that are present in the production environment and in the food chain. Through mechanisms of horizontal gene transfer, co-resistance, cross-resistance, and gene up-regulation, resistance to one compound may confer resistance and multi-drug resistance to other compounds.

There exist significant gaps in knowledge related to the use of fungicides associated with antimicrobials in worldwide plant agriculture, and the effects of such uses on the evolution and selection of resistance in human and animal pathogens. Additional data, including surveillance and testing, are needed to complete comprehensive risk assessments and identify sustainable plant health practices that are less dependent upon pesticide use.

The report suggests the consideration of risk assessment of pesticides on AMR development and proper action regarding the management of antimicrobial-associated pesticides, as well as the use of integrated pest management practices to reduce reliance on pesticides. The authors stress that training users in the responsible application of antimicrobial-associated pesticides and the consequences of irresponsible use is a “critically high priority” in countries with developed economies and in low- and middle-income countries alike.