The grey banded leaf weevil (Ethemaia sellata) has been detected attacking canola crops across the Wimmera Mallee. Growers are reporting extensive damage to emerging canola seedlings. In one particular canola paddock cotyledons and adult leaves were nibbled at or missing entirely, and damage was occurring despite a pre-emergent spray of Endosulfan. Weevils were caught using some pitfall traps and identified by the SARDI entomology team. Farmers experiencing similar damage are encouraged to try and capture the weevils, using the following instructions and send them off for correct identification as soon as possible.
Adults grey banded leaf weevils are approximately 8mm long, grey in color with distinctive raised markings (bumps) and a white area on the bottom covering approximately 1/4 of the wing covers. Â
Pitfall traps – How to make and monitor quickly
Equipment
- Plastic disposable cups
- Bulb planter
Procedure
- Dig a core of soil out with the bulb planter to the depth of the cups and insert three nested plastic cups in hole.
- Replace soil around cups until soil is flush with the top of the middle cup
- Remove top cup without disturbing the other two (may need to prise it up with edge of pocket knife while holding others down) and this leaves the trap ready without a heap of dirt in it.
- It is important to get the soil to the top of the cups as your targets have little legs or none at all and can’t climb a big slippery, backward leaning wall.
- Bait with a few crumpled and bruised canola seedling tops in the bottom of the cup but not up the sides so that whatever you catch cannot use it as a ladder.
- Leave overnight and visit trap in the morning and remove the top cup, not disturbing the other, and empty contents into collecting jar.
- Replace cup and another spare one and repeat making sure the soil is up to the top of the middle cup and remove the spare one again.
- Bait trap
Pooter – For catching what is in your traps
A pooter is an instrument by which you can pick up an insect easily without injuring them and transfer them safely to a collecting jar.
Equipment
- One drinking straw
- Piece of old stocking
- Scissors
- Sticky tape
Procedure
- With the scissors, cut about one third of the bottom of the straw
- Make about a 1.5cm slit along this short piece of straw
- Cut a piece of stocking about the size of a postage stamp and hold it over the end of the slit straw
- Insert the slit straw with the piece of stocking into the end of the other piece of straw
- Tape up the joint
- When you need to pick up an insect, place the long piece of the drinking straw into your mouth, hover the other end closely over the insect and suck with the appropriate strength to make it fly up the tube
- The piece of stocking at the other end will prevent it from entering your mouth.
- Maintain the suction and place the end of the straw into collecting jar, stop sucking and the insect will probably fall out. If not a little reverse air will help
