Hazards
Wild Parsnip is a close relative of Giant Hogweed. Consequently, the sap is reported to cause severe skin rashes that are hyper-sensitive to sunlight. Rashes and sensitivity can persist for months.
First-Aid
After skin contact with sap, wash the skin carefully with soap and water; keep the exposed areas away from sunlight for at least 48 hours. If significant blistering develops, consult a physician. Application of an anti-inflammatory cream (e.g., a 0.5% hydrocortisone cream) may reduce skin irritation. In the following months, a sun block cream should be used on sensitive areas. If the sap gets into the eyes, flush with copious amounts of water and then consult a physician.
Risk Management
Wear heavy, water-resistant gloves when handling the plants. Remember to dispose of the gloves after use (heavy rubber gloves can be re-used if carefully washed with soap and water). Do not get any sap on your exposed skin! Wear water-resistant coveralls or clothing that leaves no skin exposed. Clothing may soak up the plant sap, which can then penetrate to the skin. Wear goggles when disturbing or removing the plants, as small droplets of sap may be released into the air.
Control
Mechanical Control: The best way to control wild parsnip is early detection and eradication. A very effective control method is to cut the entire root just below ground level with a sharp shovel or spade. Cutting below ground level prevents re-sprouting. Occasional mowing, especially before plants go to seed in late July, will also reduce plant populations over time. Do not hand mow Wild Parsnip due to risk of spraying sap on exposed skin!
Chemical Control: Chemical controls are effective, but should be used sparingly on quality habitats. Herbicides such as 2,4-D, tryclopyr or glyphosate can be spot applied to the basal rosette of the parsnip. Adult plants should be spot treated during the time of plant bolting until flowering (mid-May to mid-June) or in the fall targeting plants in the rosette stage. Seed stored in the soil may continue to sprout for several years, so sprayed sites should be monitored for several years for new plants.