Finding a natural way to combat pests and diseases in maize
A quest to discover naturally occurring fungi in maize may provide a new way to help protect this crop from insect pests and diseases.
Maize grown for silage or grain is an important crop in New Zealand. Over the last 20 years, the area planted for maize silage has more than doubled as farmers are using it as a supplementary feed for dairy cows during winter.
Research in the Next-Generation Biopesticides programme is exploring whether beneficial fungi that live within plant tissues, known as endophytes, may help to protect maize from insect pests and disease and provide an alternative to fungicide treatments.
For this study, Lincoln University Master’s student Jenny Brookes is investigating which endophytes are present in maize, where they occur in the plant, and what impact they have on insect pests and diseases. Over the last two summers, she has sampled maize plants from across New Zealand, isolated more than 600 endophytes and identified 200 species using DNA analysis.
The team were surprised by the large number and diversity of endophytes collected. “We were not expecting to find even half of that number,” says Jenny. They now have the task of testing the specimens to see which ones may offer benefits to the plants and have potential as biopesticides.
“The next steps will be to narrow down the number of candidates to about 10, which we will take through for testing their efficacy against insects and disease,” she explains.
Jenny will infect maize plants with disease-causing agents, like the Fusarium fungus that causes ear rot, and establish whether any of these endophytes are protective.
The occurrence of insect pests and diseases in maize is ongoing and can be cyclic, explains Jenny, whether this leads to significant plant loss depends on the crop’s location and growing conditions, and is also influenced by seed type and time of harvesting.
Ultimately, the research team are looking for endophytes that can help combat some of the economically important diseases of maize in New Zealand such as northern leaf blight, eyespot, and stalk and ear rots and insect pests such as Argentine stem weevil, greasy cutworm, black beetle and grass grub.
Alongside Jenny’s research, Lincoln PhD student Michal Kuchár is using similar techniques to identify beneficial endophytes in brassicas. Both students are supported by funding from the Ministry of Business, Innovation and Employment, Grasslanz Technology and the Foundation for Arable Research