Disease surveillance findings and preparing for the 2020 growing season
As a result of summer rainfall, weed and crop regrowth are occurring in many areas across the wheatbelt.
Plant pathologist Ciara Beard (DPIRD) is urging growers to consider potential disease carryover into the upcoming crop growing season as this vegetation can serve as a ‘green bridge’ for diseases and pests. Diseases, such as cereal rusts and powdery mildew, root diseases, and viruses spread by aphids can be harboured on weeds and/or volunteers and in autumn these could spread to newly emerging crops.
To minimise this risk, growers and agronomists are encouraged to monitor any green bridge for aphids and disease so that timely action can be taken to identify the pathogen, and limit the spread and build-up of inoculum.
Green bridge aphid or disease reports can be made online from the paddock using DPIRD’s MyPestGuide Reporter or PestFax Reporter apps. Or you can contact your local DPIRD office. If using the My Pest Guide Reporter app in the “Send report to” section select “Show more” and then choose “Green bridge survey” from the list.’
Should you find rust on volunteer cereals or grasses, you are encouraged to send samples for pathotype analysis in paper envelopes to the national rust survey. Instructions and the submission form are available here.
DPIRD regional staff are conducting surveys around the regions this month to gauge the risk associated with weeds, insects and disease in green bridge vegetation. This work will allow advice to be delivered with regard to priority disease risks this season and appropriate management strategies.
Disease management tips for 2020
Control the green bridge
It is crucial that weeds and crop volunteers, including those along fencelines, are killed at least one month prior to the start of the cropping program to reduce potential pest and disease carryover between green regrowth and emerging crops. Results of the green bridge survey will be released in late April/early May to summarise what disease(s) were found and the implications for the 2020 season.
Consider what crop diseases occurred on your property and in your local area in 2019 as a guide to what may be a risk for your crops in 2020
A new crop disease surveillance project co-funded by DPIRD and GRDC commenced in July last year and identified the incidence and severity of diseases in wheat, barley, oats, canola and pulses. DPIRD plant pathology staff visited over 300 unique sites during the 2019 surveillance activities and 250 plant samples were collected to assess for endemic and exotic diseases. Despite 2019 being a drier than average year in many areas the stubble borne diseases yellow spot in wheat, spot-type net blotch in barley, and septoria avenae blotch in oats were found at high incidence across most port zones, although at generally lesser severity than in previous wetter seasons. Though at far lower incidence, there was some wheat powdery mildew observed in the Esperance region, and wheat leaf rust, barley powdery mildew and barley ramularia found in the Albany region. Disease in canola and pulses, including damaging levels of sclerotinia, was minimal. These reports are displayed on DPIRD’s PestFax map and a summary of all the 2019 surveillance results is available at DPIRD’s Crop disease surveillance activities page.
The key implications of the surveillance finds in 2019 are that cereal stubble borne diseases are likely to be moderate to high risk in the 2020 season. The widespread incidence of spot-type net blotch in barley indicates this disease, in particular, is a constant concern across the WA grainbelt.
Use an integrated disease management approach
Plan variety choices and crop rotations to minimise disease risks and avoid over reliance on fungicides. DPIRD’s 2020 Western Australian Crop Sowing Guide includes variety disease ratings, and there are tables of fungicide registrations available on the DPIRD website to assist with this.
For more information about this disease surveillance or cereal disease management in general contact Ciara Beard, Plant Pathologist, Geraldton on +61 (0)438 468 484 or Geoff Thomas, Plant Pathologist, South Perth on +61 (0)428 947 287.
Article author: Ciara Beard (DPIRD Geraldton).
Article input: Geoff Thomas (DPIRD South Perth).