Tips on how to identify insects in emerging crops
During autumn, changing seasonal conditions trigger a burst of activity from a range of crop establishment pests, and also beneficial species.
As crops emerge, it is important to remember that differences in pest biology, as well as seasonal differences, mean that no one tactic or approach will effectively control pest issues in all situations. Therefore, frequently checking crops during the first 3-5 weeks is a key to early detection of pest issues and intervention as necessary to ensure crops get away to a healthy start.
When checking crops sometimes pest damage is visibly obvious but finding and identifying what insect pest, or combination of pests, is causing the damage may not always be so simple.
The following tips might be useful to identify damaging insect pests in emerging crops;
- Look up and down the seeding rows for missing plants that may have been chewed off at the base or plants with visible chewing damage.
- Look for insects around and under chewed or missing plants. Don't forget to check under the stubble in the inter-rows.
- What type of damage has the plant sustained? Understanding the preferred feeding methods and mouth parts of insects can help narrow the lists of culprit insects. For example chewing damage above or below ground is the feeding method favoured by caterpillars, European earwigs, weevils and other beetles. Sucking-type damage appears as wilting and yellowing of plants and is favoured by aphids and Rutherglen bugs who have piercing and sucking mouthparts.
- Still can't find a pest? Place a pitfall trap near the damage, this is just a plastic cup dug into the ground so the top is flush with the soil surface. Put about 10mL of water into it and come back after 24 hours. This has been especially useful in detecting the presence of weevils, slaters and European earwigs. European earwigs are one of the few pests that if numbers are high, can damage well established crops especially if they chew through the stem.
- Have you found an insect in the paddock that you have not seen before? It could be an incidental or it could be a new pest species. Consider taking the time to get it identified. It is hard to identify an insect from a verbal description. But there are a few things you can do. Have a phone or tablet that takes photos? Take a photo and email it to Dusty Severtson. We also encourage taking a photo and attaching it to your report when using the PestFax Reporter app.
DAFWA entomologist Svetlana Micic goes into more detail about monitoring crops for insect damage and identifying them in the department’s How to monitor for early season pests YouTube video.
If you do find insects in the paddock make sure they are correctly identified as not all insects that are caught may be crop pests.
The department offers a multiple of free insect identification services and for more information on these refer to the PestFax article Get your insects identified for free with DAFWA.
For more information on monitoring insects in emerging crops refer to the department’s Monitoring insects and other crop pests.
For more information contact Svetlana Micic, Research Officer, Albany on +61 (0)8 9892 8591 or Dustin Severtson, Development Officer, South Perth on +61 (0)8 9368 3249.