Biological control of ragwort in the New Zealand dairy sector: an ex-post economic analysis. Issue 3 (2nd July 2016)

• Record Type: Journal Article
• Authors: Fowler, SV; Gourlay, AH; Hill, R
• Is Part Of: New Zealand journal of agricultural research. Volume 59:Issue 3(2016)
• Page Start: 205
• Page End: 215
• Publication Date: 2016-07-02
• Subjects: Biological control -- cost benefit -- Jacobaea vulgaris -- Longitarsus jacobaeae -- net present value -- New Zealand -- ragwort flea beetle; Agriculture -- Periodicals; Agriculture -- New Zealand -- Periodicals; Animal culture -- Periodicals; Animal culture -- New Zealand -- Periodicals; 630.99305
• DOI: 10.1080/00288233.2016.1170050
• Languages: English
• ISSNs: 0028-8233

Abstract

ABSTRACT: Ragwort flea beetle, released in New Zealand in 1983, successfully controls ragwort, except in regions that receive very high rainfall such as the West Coast of South Island. If biocontrol had not been instigated, expenditure on ragwort control across New Zealand dairy farms in 2015 would have been an estimated NZ$64 million (adjusted for inflation and national herd size). Data on the impact of the flea beetle were used to estimate the national benefit from reduced control costs to dairy farms from biocontrol which, in 2015, was NZ$44 million. Ragwort biocontrol in New Zealand was attempted from 1926, and a net present value (NPV) analysis gave a 14:1 benefit:cost ratio, which remained positive in robust sensitivity testing. In New Zealand, the flea beetle was rejected as a biocontrol agent in 1933 on anecdotal evidence of its low impact on ragwort. This poor decision cost the dairy industry NZ$8.6 billion (NPV) from 1945 to 1999.