Biosecurity and aphids in New Zealand.
About 110 introduced aphid species (Hemiptera: Aphididae) have been recorded in New Zealand. Only 12 of these are indigenous species. On average there has been about one new aphid incursion into New Zealand per year over the last 130 years although this rate has declined dramatically in recent years. The origins of introduced aphids appear to include most parts of the globe. Many introduced aphids damage economically important plants through their feeding and transmitting plant viruses. Less quantifiable environmental impacts include injury to native plants and the displacement of native aphids on their host plants. Aspects of aphid biology, such as small size, parthenogenetic reproduction, high reproductive rates, short generation time, rapid dispersal and eruptive population dynamics, pose particularly difficult challenges for aphid biosecurity in New Zealand.