Pest And Disease Update – September 2022

We’re in the middle of a busy disease and pest season, where it’s imperative to keep a close eye on crops to prevent any damage…
September 14, 2022Agronomics Back to All

We’re in the middle of a busy disease and pest season, where it’s imperative to keep a close eye on crops to prevent any damage or losses. At the time of writing, here’s what our agronomists are seeing:


Insect Update 



  • Pea weevils are about, and now is the time when they will move from native vegetation into crops. Now is the time to spray before they lay eggs in crop.
  • In short – if doing a pass, spray for grubs. From now on we need to be vigilant and proactive for grubs.
  • If you have seen red-legged earth mites, now is the time to spray before they lay. Timerite says 17th September for most of the YP area.
  • Currently finding a few winged blue green aphids and cowpea aphids in lentils, but not at threshold levels yet. We expect to see more once the weather warms up. Continue with anti-feed for now.


  • Armyworm/Barley Grub – keep monitoring crops, we haven’t really seen many on the YP yet, but we are seeing low numbers in the Mid North where insecticides haven’t been used in crop this season. If you notice chewing damage, look for armyworm, and chuck a bug spray in if doing a pass. 
  • Aphids – seeing the occasional Russian wheat aphid around the YP if you didn’t have imidacloprid on seed dressing. It is worth checking crops. All cereals will need an anti-feed product by flag leaf anyway.


  • Diamondback moth is not an issue yet, but we advise you to keep monitoring crops, especially toward the end of flowering. If thresholds are met, put a spray out.
  • Continue to monitor for aphids but not an issue. Only spray if thresholds are met. 



Disease Update:



  • Blackleg is currently posing a moderate-high risk depending on area and variety. Early sown crops are more likely to get infected earlier. 
  • If you’re a canola grower growing similar varieties with similar blackleg resistance groups – expect to see more blackleg. 
  • Crops appear to be cleaner when varieties have been rotated to different resistance groups. 
  • Sclerotinia doesn’t usually pose an issue for canola on the YP or in the Mid North. However considering how the season is shaping up with above-average rainfall it’s definitely worth keeping an eye out for it. Most canola crops would have had a Prosaro application around 30% flowering.

Blackleg Canola.JPG

(Above) Blackleg in Canola



  • Powdery mildew is very persistent across all wheat varieties, especially susceptible varieties, such as Chief CL and even Sceptre to a point, especially where crops had good early vigour. Infected crops will require a good quality fungicide application such as Prosaro or Maxentis.
  • Low levels of Septoria were seen early on, and we advise continuing preventative fungicides.

Septoria Wheat.JPGIncreasing Degrees of Septoria.JPG

(Above) Septoria in wheat, increasing degrees on septoria in wheat.

Powdery Milder - Stem.jpgpowdery wheat.jpegPowdery Mildew - Leaf.jpg

Above – Powedery mildew stem and leaf.



  • Both spot and net form net blotch are very active within barley, especially in crops that didn’t receive an early propiconazole spray. Warmer conditions and rainfall will increase the risk of disease spread within the plant canopy. 
  • Aim to get the second fungicide applied on flag leaf emergence.

spot form in barley.jpeg

(Above: Spot form net blotch in barley)


Wheat & Barley:

  • It’s a rust year, for sure. Leaf rust and stripe rust are the most active we have seen in the last decade. Any crops that weren’t protected by either an early epoxiconazole or propiconazole have exploded with orange hot spots. There could be more around this year as some haven’t been as proactive with preventatives, having not seen rust for a number of years. 
  • A proactive approach is required to control and prevent rust. Rust is highly and easily spreadable. If an infected crop is sprayed, all the activity of the fungicide will be used to ‘cure’ the infection in the paddock, leaving nothing to prevent further infection. This situation will open the crop to re-infection significantly sooner. On the other hand, if you spray fungicide onto a rust-free crop, it will prevent the establishment of rust. As always, prevention is better than a cure.
  • Overall, look to protect cereals with fungicide, especially the flag leaf, to maintain leaf area for maximum yield potential.

Wheat Stripe Rust (2).jpegWheat Stripe Rust.jpeg

(Above) Stripe Rust in wheat

Leaf Rust.JPG

(Above) Leaf Rust



  • Grey mould is already present in some paddocks and will likely take off in the next couple of weeks with plenty of moisture and warmer temperatures. Keep an eye on your lentils, vetch, and chickpeas. 
  • Lentils – Sclerotinia will start showing up soon and can take off with favourable conditions.
  • Low-levels of ascochyta are not hard to find and is primed to go nuts with these consistent rain fronts.
  • Powdery mildew is also present in peas. We advise putting out a preventative if doing a pass.
  • Spray ahead of rain fronts to keep new growth protected.
  • Asocochyta is out there – and we’re finding low levels in the Mid North.
  • Beans – Chocolate Spot will start to ramp up with the warmer wet conditions. Make sure preventative sprays are on to protect new growth.
  • Beans – also seen Cercospora early on, more likely to now to be less on an issue with fungicides targeting Ascochyta and Chocolate Spot.

Ascochyta Lentils.JPG

Asocochyta in lentils

cercospara in beans.jpeg

Cercospora in beans

downy mildew.jpeg

Downy mildew in peas.

blackspot peas.jpeg

Blackspot in peas.