The weed that causes Asthma is-

Parthenium hysterophorous is an invasive species belonging to the family Asteraceae.
It invades disturbed land, including roadsides. It infests pastures and farmland also known as famine weed.
This plant produces allelopathic chemicals that suppress crop and pasture plants and allergens that affect humans and livestock. This weed causes respiratory problems and can trigger asthmatic allergies.