Disease symptoms include stunted growth and leaf yellowing, both of which affect the plant’s ability to photosynthesise and can lead to significant yield losses. Autumn sown crops are especially vulnerable.
FAR, in collaboration with Plant & Food Research, has completed two years of a three year MPI Sustainable Farming Fund project aimed at improving BYDV management in cereal crops. One component of the research has been to test the accuracy of the rule of thumb that wheat plants become tolerant to aphid transmitted BYDV when they reach the start of stem extension, at growth stage 31 (GS31).
In this study, wheat plants were infected with BYDV by confining ten aphids collected from a BYDV-infected laboratory colony to plants at a range of growth stages using clip-cages. The work was carried out in insect screened shade houses to prevent aphids from infecting plants at the wrong growth stage. The results of three trials showed an average yield loss of 35% when all of the plants were infected at GS31.
Last season the work aimed to identify when, during stem extension, the crop became more tolerant, and the results show that there was still a significant yield loss when infection was initiated at GS33.
As the shade house is an artificial environment where all of the plants have been deliberately infected at the appropriate growth stages, it is not expected that the same yield losses will occur on-farm. With this in mind, the next step is to take the research to the field. The plan is to use the weigh wagon to enable tramlines to receive different treatments. This should account for any spatial variability of virus carrying aphids that is more likely to occur in a small plot trial.
This year’s trials will be set up with four treatments: Insecticide seed treatment, Aphids controlled to GS31; Aphids controlled to GS39 and an IPM approach.
Sustainable Farming Fund Project: 404939, PGG Wrightson Grain, Dow Agrosciences, Luisetti Seeds, Bayer Crop Science