Problem Statement: A grape-producing company in Southern Namibia is currently the largest user of methyl bromide in Namibia, using in excess of 150kg of methyl bromide annually (of a countrywide annual usage of around 200kg). The vineyards are irrigated as they are situated in an hyper-arid desert environment with almost no natural vegetation. The company is currently being advised to apply methyl bromide for soil fumigation in vineyards as a precautionary measure to reduce and prevent nematode infestations of rootstocks. However it is quite possible that nematode pests do not occur in the area, but in the absence of even basic taxonomic surveys it is impossible to predict the likely risk. Since methyl bromide contributes to ozone depletion, every effort needs to be taken to avoid its use and an international agreement has been reached to phase out methyl bromide usage worldwide.

Methods: Appropriate simple taxonomic surveys would allow for sound planning and environmentally responsible activities.

Outcomes and Impacts: No information on the possible presence of pest nematodes is available from the area, but expert opinion suggests that it is unlikely that any nematodes of agricultural concern occur naturally here. Even if problem nematodes do occur, the company is likely to incur significant expense when permission to use methyl bromide is withdrawn.

Lessons: Before implementing expensive, environmentally harmful and time-consuming prophylactic treatment of possible pest problems, it should be determined whether a realistic threat exists.