What Growers Need to Know
Leaf Tip Necrosis: What Is It? Over recent seasons, Sunmax™ wheat has shown great performance across Southern Queensland and Northern NSW, especially when planted in early to mid-April. Known for its strong rust resistance, Sunmax™ has become a favourite among many growers. However, some have noticed the appearance of Leaf Tip Necrosis (LTN), an unsightly but ultimately harmless condition.
What Does It Look Like? LTN typically appears as dieback on the flag leaf, starting from the tip and margins, often forming blotchy, dead areas. This can sometimes be mistaken for foliar diseases like yellow leaf spot, but it’s important to distinguish the two, as LTN is not disease-related.
Why Does It Happen? LTN expression depends on both the wheat variety and the seasonal growing conditions, particularly during flag leaf emergence and early grain fill. For example, in 2021, many Sunmax™ crops benefited from early planting and strong rainfall in May and June. However, the dry spell that followed in July and August led to increased visibility of LTN symptoms.
The Genetics Behind It The presence of certain adult plant rust resistance (APR) genes, including Lr46/Yr29/Sr58, is associated with LTN. These genes offer robust and durable protection against all three rusts and powdery mildew, which is why they’re a valuable inclusion in commercial varieties like Sunmax™. While these genes are a huge agronomic advantage, their link to LTN is a known and well-understood trade-off.
Practical Takeaway for Growers If you’re seeing Leaf Tip Necrosis in your Sunmax™ wheat:
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- Don’t confuse it with disease—LTN isn’t infectious.
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- Fungicides won’t help, as it’s not a fungal issue.
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- Your yield potential remains strong, even if LTN symptoms appear.
At Dawson Ag, we understand how important it is to distinguish between real threats and cosmetic symptoms. If you’re unsure, book a paddock visit or soil test with our team. We service across Dalby, Chinchilla, Goondiwindi, Moonie, Roma, Tara, North Star, Wandoan, and the South Burnett.
Need Backup?
Our agronomists are here to help you make sense of your crop’s performance. Contact us today or check out our Soil Testing, Kelly Chain Hire, and Farm Management Partnerships pages for more support.
