Which Asteraceae plants are considered troublesome weeds?

Within the Asteraceae family, several plants are recognized as particularly troublesome weeds. According to Britannica, the most notable among these are:

• Ragweeds (Ambrosia): Specifically, common ragweed (Ambrosia artemisiifolia) and giant ragweed (Ambrosia trifida) are significant because they are major causes of hay fever.1
• Dandelions (Taraxacum): These are widely considered troublesome due to their effective seed distribution, which utilizes wind currents via parachute-like structures called pappi.1
• Thistles (Carduus, Cirsium, and Onopordum): These are frequently cited as among the most problematic weeds within the family.1

Additionally, other members of the family can become weeds depending on the context, as a weed is generally defined as any plant growing where it is not wanted. For example, cockleburs (Xanthium species) can lower the value of animal products like wool, while tarweeds (Madia species) can complicate animal care. Other species, such as prickly lettuce (Lactuca scariola) and sow thistle (Sonchus species), are considered problematic because they serve as hosts for plant disease organisms.2