This rapid assessment shows:

 Risk of entry – unlikely (on produce) Although Macchiademus diplopterus has been intercepted on imported produce on several occasions, it has only been found in large numbers once and since 2005 it has mainly been found during the winter (November to March) when outdoor temperatures are too low for the adults to fly. 

Risk of establishment – outdoors is unlikely, very unlikely under protection Outdoor establishment is unlikely because the climates of the Western Cape and the UK are very different and this species is unlikely to survive the prolonged cold and damp conditions of British winters except where they are protected, e.g. in farm buildings. This species has not been observed in protected crops. 

Rate of spread – moderate pace If it did establish, adults are strong fliers and can disperse several kms when temperatures are above 21ºC. Spread is likely to be faster in trade. 

Economic impact – may have a very small impact to cereals 

Poor overwintering survival coupled with low population densities indicate that any impacts are expected to be very small. 

Endangered area – Where populations have been able to overwinter and establish on grasses and grain crops in the vicinity, densities are likely to be highest in the warmest and driest areas of eastern England but these are still significantly cooler and wetter than areas of South Africa where it as a damaging pest. 

Risk management - pesticides. Control on cereal crops would probably be relatively straightforward, in the absence of insecticide resistance, but it could involve additional treatments and there is some uncertainty concerning the effectiveness of available products.