RESEARCH by the Department of Agriculture to overcome pest problems on sweet corn exports from WA to Japan has produced promising preliminary results.
Department entomologist Francis De Lima said Japan's nil tolerance for live insects on sweet corn imports meant contaminated consignments had to undergo fumigation treatment, using methyl bromide, at the exporters expense.
"The treatment kills the insects, but it also turns the green leaf sheaths an unattractive brown colour, rendering the corn unsaleable or severely downgraded in price," Dr De Lima said.
The research into a post-harvest treatment to ensure no live insects survived on corn shipped to Japan, which began in July 2001, was partly funded by Horticulture Australia using the National Vegetable Growers levy.
"It had involved researchers exposing the pests including include mites, thrips, aphids and bud worm caterpillars, to a carbon dioxide atmosphere mixed with phosphine gas for varying lengths of time.
"The preliminary results are very encouraging but the challenge now is to develop a practical treatment program to fit the short interval between picking and air-freighting to overseas markets, which ranges from six to16 hours," he said.
Dr De Lima said that previous research had led to WA corn growers using a combined effort of crop inspections and insecticide applications, together with post harvest grading inspections and storage in controlled atmosphere or cold treatment.