Tucson Pollen Today and Tomorrow - October

Pollen counts are continuing to increase.  The relatively dry summer monsoon has promoted new growth of weeds but this year's low rainfall is likely to reduce the usual levels of weed pollen this fall.  The weeds include  Ambrosia ambrosiodes (canyon ragweed),  Ambrosia deltoidea (triangle leaf bursage, rabbit bush), and Salsola (Russian Thistle or Tumbleweed).  Russian Thistle is beginning to flower, but neither Canyon Ragweed nor Rabbit Bush are flowering.   Ambrosia confertiflora (Slimleaf Bursage) and Amaranthus palmeri (Carelessweed) have reached maturity and are releasing pollen.  Non-native grasses including Bermuda grass (Cynodon dactylon), Eragrostis Lehmanniana (Lovegrass) and Buffelgrass (Pennisetum ciliare) have been releasing pollen.  Native grasses such as Aristida (Threeawn), Bouteloua (Grama Grass) and Eragrostis Lehmanniana (Lovegrass) have also been flowering.  These grasses have been flowering for at least 2 months and most are now going to seed.  The moist warm soil and higher humidity during the monsoon has caused mold growth, and when the surface layers of soil dry up, airborne spores will become a problem for mold-sensitive people.

Note:  This information is based on ongoing observation of flowering allergenic plants in the Tucson metropolitan area, and not on pollen counts.   Appearance and persistence of any particular airborne pollen species in the air usually lags behind the onset of flowering of the plant of origin.                                                                        Back

Disclaimer:   This site is for educational purposes only.  Any information that you have found in this web site is not intended to replace medical care or advice given to you by your own physicians. You should consider consulting your local medical library and other web sites for additional information. 

Comments and suggestions welcome!   Email: schumach@u.arizona.edu
Content Owner:  Michael J. Schumacher, MB, FRACP, The University of Arizona
Updated 9/2009