Four to one: Crop pest discovery could have wide-reaching benefits
The global research effort identified that four of the world's most destructive agricultural pests are in fact one and the same fruit fly. It is hoped the finding will also aid efforts to combat the ability of these harmful insects to reproduce, experts have said.
The so-called oriental, Philippine, invasive and Asian papaya fruit flies, the study shows, all belong to the same biological species, Bactrocera dorsalis, which is causing incalculable damage to horticultural industries and food security across many parts of the world.
The international collaborative effort, involving close to 50 researchers from 20 countries, began in 2009 and was coordinated by FAO and the International Atomic Energy Agency. It followed an integrative approach, examining evidence across a range of disciplines.
The ability to precisely identify pests is central to pest management, including quarantine measures or bans applied to internationally traded food and agriculture products such as fruit and vegetables.
Keeping exotic fruit flies out is a major concern for many countries. The study's findings mean that trade restrictions linked to the oriental fruit fly should now fall away in cases where the insect is present in both the importing and exporting country, according to Jorge Hendrichs, who was involved in the study.
"This outcome has major implications for global plant biosecurity, especially for developing countries in Africa and Asia," said the study's lead author, Mark Schutze, from the Queensland University of Technology.
"For example, the invasive—now oriental—fruit fly has devastated African fruit production with crop losses exceeding 80 percent and has led to widespread trade restrictions with refusal of shipments of products into Asia, Europe and Japan, and significant economic and social impacts on farming communities.”
The findings of the study will also simplify techniques like the use of sterilised males to prevent the growth of pest populations.
A form of insect birth control, the sterile insect technique involves releasing mass-bred male flies, which have been sterilised by low doses of radiation, into infested areas where they mate with wild females.
These do not produce offspring and as a result, the technique can suppress, if applied systematically on an area-wide basis, populations of wild flies in an environmentally friendly way.
The researchers have demonstrated that the four fruit flies freely interbreed, which means that instead of using males from the four supposedly different species, mass-produced sterile oriental fruit fly males can now be used against all the different populations of this major pest.
"Globally, accepting these four pests as a single species will lead to reduced barriers to international trade, improved pest management, facilitated trans-boundary cooperation, more effective quarantine measures, the wider application of established post-harvest treatments, improved fundamental research and, most importantly, enhanced food security for some of the world's poorest nations," Schutze said.
Due to the findings, the four previously considered distinct fruit-fly species will now be combined under the single name Bactrocera dorsalis, the oriental fruit fly.