Entomologists at the Tasmanian Institute of Agriculture (TIA) are advising berry growers in the state to be aware of an emerging pest, the Bronze Leaf Beetle.
Bronze Leaf Beetles (Diachus auratus) chew on leaves, flowers and fruits, causing poor fruit quality and reduced yields. TIA entomologist Dr Lynne Forster has warned the beetle can cause significant damage to berry crops over only a few weeks.
"The Bronze Leaf Beetle is native to Central America and was first sighted in Australia in 1986. While it's appearance in Tasmania is not new, it is becoming an increasing problem that fruit growers need to be aware of while they are preparing for the next season," Dr Forster said.
"Outbreaks in recent years have caused significant damage to berry crops in Tasmania."
The beetle is about two-millimetres in size, shiny and is 'bullet-shaped' with a flat head.
"Monitoring for Bronze Leaf Beetle is essential for berry growers in preparation for the next season. It's especially important to monitor in polytunnel systems where the beetle may thrive in warmer microclimates," Dr Forster said.
The beetle's eggs and larvae are concealed in dark cases that can be easily mistaken for waste from caterpillars and their feeding patterns on leaves mimic caterpillar damage.
"A further challenge is that it's difficult to control because there are no known registered sprays or biocontrol agents – that's why monitoring is so important," Dr Forster said.
"We're urging growers to keep an eye out for these pests. This can be done by setting up yellow sticky traps at entrances and in the middle of polytunnels and above the crop.
"Another preventative action is to minimise weeds and monitor weeds inside and outside polytunnels.
"It's important to regularly check young leaves on growing tips, flowers and fruit, as well as boundary plants. Look for chewed holes and chewed and shredded petals."
The beetle might not just be a problem for berry growers.
"Overseas the beetle has been recorded on a wide range of fruiting plants and we're concerned that it has the potential to spread to grapes, avocadoes, apples and plums. All fruit growers should be on the lookout for this beetle," Dr Forster said.
TIA entomologists are examining ways to effectively control the beetle and are conducting research that's supported by the Raspberry and Blackberry research and development levy as part of the Hort Innovation funded project: Integrated pest management approaches to address pest challenges in raspberries and blackberries.
"We recommend consulting an agronomist for advice if you do find Bronze Leaf Beetles," Dr Forster said.
"We are currently researching the biology of this pest so we can develop practical and sustainable management practices to help berry growers."
