CropAlert — Ascochyta, Blackspot Manager,BYDV & Rust
The early break this season has been great for cropping, but warm, moist conditions have also favoured a number of pests and diseases. The following Crop Alert is a round-up of the pests and diseases we have heard about so far this season, and what to look out for in the coming weeks.
Ascochyta in volunteer chickpeas: Ascochyta was detected in volunteer PBA Slasher chickpeas near Donald. Ascochyta can increase rapidly on volunteer chickpeas and infect emerging crops. Therefore, control volunteer chickpeas to prevent infection of emerging chickpea crops. Then check chickpea crops for Ascochyta throughout the growing season, even varieties rated as Resistant. More information GRDC Chickpea Disease Management Fact Sheet.
Blackspot manager for field pea: The latest blackspot report for Victoria (22 May 2014) is on the DAFWA website. Early June is the considered safest time to sow field peas in areas north of the Divide to avoid spore showers and optimise yield. More information Field Pea Disease Management Strategy.
Cereal aphids and BYDV: Cereal aphids have been detected in several early sown barley crops northeast of Ouyen in the Mallee, as reported in PestFacts Issue No. 3. Aphids are sap-suckers and may cause yellowing and wilting of plants when in high numbers. They can also spread barley yellow dwarf virus (BYDV) which is more severe in early sown crops. Be on the lookout for aphids and control if necessary. More information Aphids in winter cereals and GRDC Barley Yellow Dwarf Virus Fact Sheet.
Cereal rusts: In most parts of Victoria there has was limited green bridge over the summer and early autumn to host rust. However, rust spores can travel long distances and early reports of stripe rust (Griffith, NSW) and leaf rust (Wharminda, Eyre Peninsula SA and Quirindi, Liverpool Plains NSW) suggest it will be a good idea check crops regularly for rust, especially where susceptible and very susceptible varieties are grown. Review the resistance ratings of varieties with the Victorian Cereal Disease Guide.
Septoria tritici blotch (STB): In the higher rainfall regions of the Wimmera and Western District Septoria tritici blotch of wheat is the disease to watch this year. Strains of the STB fungus with resistance to some triazole (Group 3) fungicides were recently detected in Victoria by Dr Andrew Milgate, NSW DPI. To prolong the life of this fungicide group it will be important to have a fungicide strategy that reduces selection pressure for resistance strains of the STB fungus. More information DEPI Septoria Tritici Blotch of Wheat Dr Milgate will be in Victoria for a series of grower talks on the management of Septoria tritici blotch fungicide resistance in early August, at Nhill, Horsham, Derrinallum, and Bannockburn.
Other of diseases of interest: Stubble borne diseases: The predominant diseases to watch out for in Victorian during 2014 will be stubble borne diseases like yellow leaf spot in wheat and scald, the spot and net forms of net blotch in barley. In pulses, watch out for ascochyta and botrytis in chickpeas and lentils, as well as blackspot in field peas. Soil borne diseases: Rhizoctonia root rot, take-all and crown rot are all high risk for 2014. Expect to see symptoms of Rhizoctonia early, if Rhizoctonia is a problem in your area. The symptoms of take-all and crown rot will be apparent later in the season, if paddocks have a history of these diseases. Also watch out for root lesion nematodes.
Pulse rust: Vetch rust was identified on sample from the Mallee. The vetch also had ascochyta and chocolate spot which indicates that conditions are suitable for other pulse diseases.
Exotic diseases: When out and about, it’s always a good idea to keep an eye for potentially exotic (not in Victoria) pests and diseases. More information on exotics can be obtained from the DEPI Crop Safe program and the Farm Biosecurity Manual. It is also extremely important not to accidentally introduce exotic pests and diseases into Australia after travelling overseas. This risk can be minimised by having a biosecurity hygiene plan following overseas travel. A basic biosecurity hygiene plan includes washing clothes
and cleaning footwear before returning to Australia. If high risk areas have been visited, consider leaving clothing and footwear behind. Remind family members, employees or others travelling to also take these precautions.
