Stripe Rust in Durum
Last year the new Yr198 stripe rust pathotype caused a lot of our main durum wheat varieties stripe rust ratings to fall from MR (moderately resistant) in 2019, to MS (moderately susceptible) in 2020. The exception being Westcourt and Jandaroi which remained MR. Stripe rust is a biotrophic pathogen which needs a living plant host to survive.
The disease can develop over the summer and autumn months on volunteer barley, wheat, barley grass, triticale and phalaris. This creates a green bridge for spores to be blown into cereal crops in winter and early spring. Ideal conditions for the development of stripe rust in wheat are leaf wetness or high humidity for 5-6 hours at temperatures between 9-18°C, with its optimal cycling temp being 12-20°C.
Stripe rust has a latent period of approximately 10-14 days, which means that the plant is infected with the disease, however, symptoms i.e. rust pustules will not become visible until this latent period has finished.
As the pointy end of the winter crop season begins to loom it is critical that you protect the flag leaf, as it is the highest contributing leaf to yield for wheat. Before applying a fungicide, take into account the weather conditions and if they look to be conducive for disease development prior to spraying. Look at your varieties resistance rating for stripe rust. Consider maximum residue limits as this can have an influence on what product and rate you use if you need to spray. Hopefully your durum crops have stayed nice and clean in the lower canopy and are set up to finish the season strongly, providing the flag leaf is kept free of stripe rust. Please consult your local Pursehouse Rural Agronomist to discuss and tailor a fungicide strategy plan that suits your farm.
Summer Crop Planting
As soil temperatures begin to rise, growers are busy gearing up for a big summer crop plant. Maize is the firs of our main summer crops to be planted in September when the soil temperature is 12 degrees and rising at 8am. Cotton comes in next when the soil temperatures are 14 degrees and rising and sorghum closely follows when we hit 16 degrees and rising at 8am.
Before planting it is important to consider what soil pests and diseases could impact the establishment of your summer crop on a field by field basis, as a reduction in total plant population can potentially cause a yield reduction.
A few of the main diseases that can impact establishment are, Rhizoctonia, Pythium and Black Root Rot. Wireworm and cutworm are the two main soil pests affecting establishment of our main season summer crops. The risk of these diseases and soil pests can be exacerbated by extended cool conditions at planting, crop rotation and stubble load at the time of planting.
To assist with appropriate field selection and discuss the right seed treatment/s to get your summer crop off to the best start possible, please get in touch with your local Pursehouse Rural Agronomist. Find all contact information on our branch locations page at www.pursehouserural.com.au/locations
By Lochlan Lancaster – Agronomist – Pursehouse Rural Gunnedah 0437 210 204