In November Growcom, AUSVEG and the Queensland Government hosted a webinar for Queensland producers around notifiable plant pests.

The webinar recording is now available online here.

A number of useful links have also been made available to industry:

  • CGMMV disinfectant study: Darzi E, Lachman O, Smith E et al., 2020. Paths of cucumber green mottle mosaic virus disease spread and disinfectant-based management. Annals of Applied Biology 177, 374–384.

Questions and answers from the webinar:

How can I distinguish between damage caused by exotic leafminers and leafminers we already have?

Unfortunately, there is no way that we can distinguish the damage caused by a native/naturalised leafminer from an exotic leafminer. The reason being that there are a lot of other species in Australia and the damage is too similar to be distinguished via visual inspection. So really the best thing to do is report it to the exotic plant pest hotline. Keeping a sample of the leaf is crucial because we can use this DNA to confirm whether the damage comes from an exotic leafminer or not.

Are there any studies using remote sensors to detect exotic leafminers in a crop?

Here is a study relating to using remote sensors to detect exotic leafminers in a crop: https://onlinelibrary.wiley.com/doi/full/10.1002/ps.5758

What are the main beneficial groups that may offer control for the tomato potato psyllid?

It does differ between host plants. DPIRD in Western Australia have done some initial cage trials and found that green lacewing larvae have been effective in controlling or getting on top of psyllid numbers along with a range of ladybird species (adults), Mirid bugs are also known to be useful. More research needs to be done but those initial trials have been quite promising, combined with some soft chemical usage has managed to keep those numbers down, so there are certainly some options out there.

What measures do we have in place for treating red imported fire ants (RIFA) in crop? That seems to be very important for horticultural growers.

In crop creates a challenge for us, and it depends on the particular crop that is growing as to whether it can be treated while planted. We have a cropping officer in the program who works directly with farmers to come up with plans for fire ant treatment. Often that might be treatment in between crops. There is also the option of self-treatment, where the farmer may use special techniques or specific machinery to treat themselves. Overall, it depends on the exact scenario, and we always try to work with farmers to come up with the best solution.

Can cucumber green mottle mosaic virus spread through irrigation water?

Yes it can. It is highly stable and particularly in hydroponic systems it is important to have some disinfestation protocols in place to stop it coming back around. The paper I mentioned that just came out did some interesting studies in nursery where they were using different irrigation systems with nursery trays, and it showed how the irrigation water was able to move the virus within the seedling trays. As I mentioned in my talk, we are trying to pull together a CGMMV vegetable factsheet and we will share that factsheet through the usual channels when it has been completed. We will incorporate all the chemical concentrations for the disinfectants in that factsheet.

Does fall armyworm have resistance against BTs or NPV virus?

Fall armyworm’s ability to develop resistance for biological pesticides is very slow and takes a longer time to develop. But the efficacy pattern might be varied depending on the environment. Mainly in dry and open environments, efficacy on FAW is low. In humid and closed environments, it can be more effective. At this stage it is less likely to develop resistance quickly here in Australia.

Are there any NPV viruses available for fall armyworm in Australia?

At the moment, for fall armyworm, NPV virus is not available in Australia. However, some work is occurring to obtain approvals to import from overseas. It is too early to comment further on that.

Have you trialled Entrust organic (Spinosad) on fall army worm?

We have not conducted any replicated plot trial on Spinosad in organic crop. We have collected a set of post-spray samples from an organic sweetcorn crop that was sprayed with Entrust.  The results indicated a significant reduction of small size larvae (first and second instars). Further work is planned for next season.