Don’t Confuse Sphagnum Moss With Peat Moss
By Gerry Hood
President, Canadian Sphagnum Peat Moss Association
You may have read about a fungal disease call Cutaneous Sporotrichosis, a chronic infection identified by skin lesions. The fungus that causes this disease has been found in several kinds of organic material and, because in extremely rare cases this disease can cause death, gardeners are rightfully concerned about protecting themselves from contracting it. Unfortunately, however, some of the information circulating about how gardeners can contract this disease has been inaccurate. It confuses two separate products; one of which is known to carry the fungus and one of which does not.
One of the materials known to carry the Sporotrichosis fungus is sphagnum moss. Most frequently used by the floral industry to line wire baskets, this product is frequently being confused with sphagnum peat moss, a soil conditioner known for its ability to bind sandy soils, loosen clay soils and retain water. The difference is an important one. While there have been cases of Sporotrichosis resulting from handling sphagnum moss, there have been no cases as a result of handling sphagnum peat moss. Sphagnum moss and sphagnum peat moss are not the same product, as many avid gardeners know.
Sphagnum moss is the living moss that grows on top of a sphagnum bog. The fungus sporotrichum schenckii is known to live in this growing moss.
Sphagnum peat moss is the dead material that accumulates as new live material grows on top and exerts pressure on the peat moss below. The fungus is not know to live in the levels of a sphagnum bog where peat forms. Harvesters of horticultural peat moss remove the top few inches of the live sphagnum moss and only harvest the peat from the lower layer.
“Living” sphagnum moss is used in the floral industry to make wreaths and to line hanging baskets. Workers in the industry have been warned to protect themselves with gloves and heavy clothing to avoid puncture wounds or scrapes. Gardeners wishing to use sphagnum moss to create their own baskets or for other uses should simply follow the same advice: Wear gloves and long sleeves to prevent coming into contact with the dried moss. No similar warning appears on Material Safety Data Sheets (MSDS) for handling sphagnum peat moss.
Gardeners worldwide use sphagnum peat moss as a soil amendment because its unique cell structure enables peat to:
Aerate plant roots by loosening heavy clay soils;
Add body to sandy soil; and
Save water by absorbing and holding moisture
Peat moss is not only effective, it’s organic and safe to use.
Written by Dr. Paul King, VP Technology,
Sun Gro Horticulture Inc.
The fungal disease Sporotrichosis has been observed for many years, and is often called Rose Gardener’s disease, since thorn pricks are a common way of introducing the fungus. Sporotrichosis is caused by the fungus Sporotrichum schenckii, and this fungus has been found in soil, on flowers and shrubs, on wood, timber, forest litter, and various mosses, including sphagnum moss.
Please note that we are specifically talking about sphagnum moss and not Peat Moss. Sphagnum moss is a living plant, which is green and light tan in colour, and its usual appearance is in long strands. Peat moss, on the other hand, is medium-to-dark brown material and has aged for thousands of years, usually under water. To our knowledge, there have not been any reported cases of Sporotrichosis caused by Canadian Sphagnum peat moss. In recent articles on this subject, published in trade magazines, there has been confusion differentiating sphagnum moss versus Sphagnum Peat Moss, and as a result, some of our customers may think that Sporotrichosis is caused by Canadian Sphagnum Peat Moss, which is obviously false.
The fungus is found throughout the United States, but it appears to be most common in the Midwest, especially in Wisconsin. Several outbreaks in other states have been traced to sphagnum moss shipped from Wisconsin. The state forest tree nurseries in Wisconsin no longer use sphagnum moss for packing seedlings.
No cases of Sporotrichosis have occurred at any of the other nurseries in Wisconsin or Michigan, since they stopped using sphagnum moss as packing material.
Sporotrichosis most often affects gardeners, nursery personnel and tree planters. Workers may contract the fungus from the soil as well as from contaminated moss. The fungus seems to increase in the moistness of most packing sheds. In some cases, the mixture of soil and moss remaining in the shed may have served as a reservoir for the fungus the following year.
Infection occurs when the spores of the fungus are introduced through a small abrasion or a scratch in the skin. In one to four weeks, a small painless blister develops at the entry point. This blister becomes inflamed, and slowly enlarges. Other areas may become infected as the fungus spreads through the lymph channels, and the lymph glands in the armpit or elbow may become enlarged and sore. But diagnosed early, the disease can be effectively treated.
Medical experts recommend that workers in nurseries, and other horticultural areas, practice disease prevention: Sphagnum moss should be stored under dry conditions; and these areas should be disinfected regularly. Workers should wear protective clothing; especially rubber gloves and long-sleeved shirts. Good personal hygiene is essential; hands and arms should be thoroughly washed with soap and water after any exposure. Lacerations and abrasions must receive special attention and prompt treatment. If sores do not heal properly, infected individuals should seek immediate medical attention.
If you would like further information on this infection, you can e-mail the CSPMA at: email@example.com