Ability to Respond Total:8 / 25Ability to Respond = ( Ease of Response + Tools in Place )
Confidence:High
Confidence Notes:
Impact
Spread
Notes
Score
Spread Rate
Dittrichia was first reported in California in Santa Clara County in 1984. It has rapidly expanded its range and has been reported in at least 26 counties in the state, from Trinity to San Diego Counties.
5
Spread Amount
Thus far it is primarily a weed of roadsides, disturbed area, open areas, and has minor movement into rangelands. However, it has been reported to move into pastures and expand in size there as livestock do not find it palatable.
4
Damage
Notes
Score
Ecological
Dittrichia forms dense stands in disturbed soils, and less dense stands in open and bare areas, but patches increase in size rapidly and seeds are easily dispersed locally and over long distances.
3
Agricultural
Currently, very little Dittrichia has invaded agricultural areas or . It is unknown whether this could be a signficant problem in the future as the species is not reported to be a major problem elsewhere. It degrades rangeland and harms livestsock.
2
Infrastructure
0
Cultural
0
Health
Plant causes severe dermatitis in some individuals.
3
Benefit
Notes
Score
Ecological
0
Agricultural
0
Infrastructure
0
Cultural
0
Health
0
Total
17
Ability to Respond
Ease of Response
Notes
Score
Detection
Very late season plant, resembles Russian thistle from a distance and flowers so late that it is difficult to detect. Can be confused with other aster species. However, since it is found along disturbed areas, it is not hard to find.
3
Control
Recent studies have shown that glyphosate and triclopyr can control the species. Generally, access to populations is easy. Difficult to control every individual as individuals are often scattered.
