▁ph y to chem ical ▁journ als ▁because ▁the ▁ses qu iter p ene ▁la ct one ▁comp ounds ▁contained ▁within ▁them ▁are ▁an ▁important ▁cause ▁of ▁all erg ic ▁contact ▁der mat itis . ▁All er gy ▁to ▁these ▁comp ounds ▁is ▁the ▁leading ▁cause ▁of ▁all erg ic ▁contact ▁der mat itis ▁in ▁flor ists ▁in ▁the ▁US . ▁Pol len ▁from ▁rag we ed ▁Amb ros ia ▁is ▁among ▁the ▁main ▁causes ▁of ▁so - called ▁hay ▁fe ver ▁in ▁the ▁United ▁States . ▁ ▁A ster aceae ▁are ▁also ▁used ▁for ▁some ▁industrial ▁purposes . ▁Mar ig old ▁( Tag etes ▁pat ula ) ▁is ▁common ▁in ▁commercial ▁p oul try ▁fe eds ▁and ▁its ▁oil ▁is ▁extracted ▁for ▁uses ▁in ▁col a ▁and ▁the ▁cig aret te ▁industry . ▁ ▁Several ▁members ▁of ▁the ▁family ▁are ▁cop ious ▁ne ct ar ▁produ cers ▁and ▁are ▁useful ▁for ▁evalu ating ▁pol lin ator ▁populations ▁during ▁their ▁blo om . ▁Cent a ure a ▁( kn ap we ed ), ▁Hel ian th us ▁ann u us ▁( dom estic ▁sun flow er ), ▁and ▁some ▁species ▁of ▁Sol id ago ▁( g old en rod ) ▁are ▁major ▁" h oney ▁plants " ▁for ▁be e keep ers . ▁Sol id ago ▁produces ▁relatively ▁high ▁protein ▁pol len , ▁which ▁helps ▁h oney ▁be es ▁over ▁winter . ▁ ▁Some ▁members ▁of ▁A ster aceae ▁are ▁econom ically ▁important ▁as ▁we eds . ▁Notable ▁in ▁the ▁United ▁States ▁are