Economical estimates of weeds: the examples of Sicyos angulatus and Abutilon theophrasti in Catalunya, Spain
Sicyos angulatus (Cucurbitaceae, EPPO List of IAP) originates from North-America and it is suspected that it has been introduced as an ornamental plant in some European countries during the 19th century. The plant was found in a maize field in Catalunya (ES) and eradicated in 2004 (see EPPO RS 2006/170). In 2005, the species was then officially declared a quarantine pest in the Order ARP/10/2005, and obligatory control measures were established. In 2005 and 2006, monitoring and eradication actions continued and will be maintained at least until 2010.
The total costs of the eradication campaign of Sicyos angulatus are estimated at 78 320 EUR for 6 years and are detailed as follows:
- 2004 costs: 3 200 EUR (destruction of the infested fields, costs of machinery, transportation, compensation to farmers at 0.20 EUR/m² for an area of 16 000 m²).
- 2005 costs: 14 220 EUR (6 months monitoring by a technical officer: 12 000 EUR; 35 days of a technical officer for manual eradication: 2 100 EUR; and use of herbicides: 120 EUR).
- 2006 costs: 12 180 EUR (6 months monitoring by a technical officer: 12 000 EUR; 3 days of manual eradication for a technical officer: 180 EUR).
- From 2007 to 2010, estimates are identical to 2006, resulting in a total of 48 720 EUR.
In order to estimate the benefits from this eradication, the costs of destroying and monitoring Sicyos angulatus in the Comarca del Pla d’Urgell (Lleida) from 2004 untill 2010 have been compared with the containment of Abutilon theophrasti (Malvaceae) in the same area, from 1980 to present. Indeed, Abutilon theophrasti is a dramatic example of a maize weed detected in 1980, which spread untill colonizing about 10 000 ha of maize in the province of LLeida (about 44% of the maize fields). The weed began to be treated chemically in 1986. The appearance of a selective active ingredient (fluroxypyr) in 1991, as well as isoxaflutole in 1997 and mesotrione in 2003 allowed its management by chemical means.
For Abutilon theophrasti, both yield losses and management costs in maize fields were taken into account between 1986 and 2005 (years for which data is available) to calculate economic estimates. Yield losses between 1980 and 1990 were estimated at 1 720 000 EUR, and 2 320 000 EUR between 1980 and 2005, resulting in a total of 4 040 000 EUR. Management costs by chemical treatments were estimated at 2 918 800 EUR. In total, the economical impact of the presence of Abutilon theophrasti in the Lleida Province is therefore estimated at about 7 million EUR between 1986 and 2005 (over a period of 26 years).
These results highlight the need for prevention and eradication programmes of weeds.
Recasens J, Conesa JA, Millàn J, Taberner A (2006) [Prevision of the agronomic impact of Sicyos angulatus as a weed in maize fields in Cataluña] (in Spanish). Proceedings of the Congresso 2006 Sociedad Espanola de Malherbologia.
Recasens J, Conesa JA, Millàn J, Taberner A (2007) [Estimation of the economic impact of an exotic weed in cultivated fields. The example of Sicyos angulatus and Abutilon theophrasti in Cataluña] (in Spanish). Phytoma España, 193 18-25.