Co-occurrence of Reniform Nematode, Rotylenchulus reniformis and Downy Mildew Fungus, Peronospora sp. on Argimone maxicana in Madhya Pradesh, India: First Report

Mexican poppy, Argemone mexicana is a medicinal plant and an objectionable weed of mustard crop. Occurrence of downy mildew (Peronospora sp.) and reniform nematode (Rotylenchulus reniformis) were recorded on A. mexicana in Satna district, Madhya Pradesh, India, during a survey in 2024-25. At the early stage of infection, infected plants developed chlorotic patches on the upper leaf surface and reddish-brown patches on the lower leaf surface. As the disease progressed, greyish-purple to reddish-brown spots appeared on both leaf surfaces. Microscopic studies revealed characteristic sporangiophores and sporangia of Peronospora sp. This is the first confirmed report of downy mildew on A. mexicana along with R. reniformis in India. This report may have ecological importance because of the medicinal value of A. mexicana and invasive nature of Peronospora sp. and R. reniformis.