Ecological, phytosanitary, and agronomic aspects of target weeds for biological control studies in Antioquia, Colombia

Biological control as part of integrated weed management represents an emerging and promising method to minimize the use and impact of herbicides on the environment. The objective of this research was to determine the ecological, phytosanitary, and agronomic status of weeds associated with crops in Antioquia, Colombia, and their potential to be chosen as candidates for biological control studies using pathogenic fungi. The research was carried out through a sampling of weeds in 35 agricultural farms, distributed in 11 municipalities and 10 different crops, on which population ecological variables such as frequency and dominance were evaluated; phytosanitary variables such as incidence and severity of foliar fungal symptoms; as well as some biological and anthropogenic aspects of these, through interviews with the farmers of each farm. The integration of these variables was proposed as an indicator to order and classify the plants according to their greater suitability to be subjected to biocontrol studies. A diversity of 75 weed species was found, with the Poaceae and Asteraceae families standing out, which together represented 43% of the population. 76% of this population presented disease symptoms, presumably of fungal origin, with the severity of up to 10% of the affected leaf area. In 22% of the species agronomic management difficulties greater than 50% were detected on a scale of 1 to 10. We indicate the following twelve weed species as candidates for future biological control studies through phytopathogenic fungi: Rumex crispus L., Digitaria horizontalis (Willd), Persicaria nepalensis (Meisn.) Miyabe, Thunbergia alata Bojer ex Sims, Melinis minutiflora Beauv., Paspalum paniculatum L., Pennisetum clandestinum Hochst. ex Chiov., Pteridium aquilinum (L.) Kunth, Sonchus oleraceus L., Erigeron bonariensis L., Bidens pilosa L., and Artemisia absinthium L. This is the first report of its kind in Colombia.