Agronomy InsightsSam N. Bartee, CCA/CAC
West Central Division Agronomist
May 3, 2010
Wheat Stripe Rust – it has Arrived in Kansas and is Spreading!
Over the past several weeks, we have been hearing about Stripe Rust and its activity in Texas and movement into Oklahoma. Generally rust diseases move progressively from the south to the north with detection in wheat fields to affirm its distribution and “south-to-north” progression. One surprising development was the first known Kansas detection in north central Kansas near Belleville (not a southern location). Additionally it was found near Hays and Manhattan. In the past few days, stripe rust has been detected in Meade, Finney and several other counties in southwestern Kansas. One can assume it will continue to show up, especially if favorable weather conditions (cool, moderately wet) continue.The question about optimum fungicide application timing always plays a major part in proper and effective treatment/control. One specific aspect of Stripe Rust is its inherent ability to spread within the plant. With this in mind, I look at taking an aggressive approach at being proactive with a fungicide application – apply as early as practical. For holding on to yield potential in wheat, it is generally all about protecting the flag leaf. If stripe rust becomes established on a wheat plant, it will cause a loss in yield – how much loss depends on a number of factors including the severity of pressure, wheat variety, overall plant health, associated environmental parameters, etc. Under the right set of conditions, it has reduced wheat yields from 40-60%.
In the case of stripe rust, I suggest two application scenarios: 1) If stripe rust is detected in field during joint/boot initiation, apply a fungicide to minimize yield reduction, or 2) If no stripe rust orother wheat disease is visible, make a fungicide application just prior to flag leaf extension.
So which types of fungicides might be the best for my above-mentioned scenarios? If no stripe rust or other diseases have been detected, the strobilurins that prevent diseases only and have good residual properties (Quadris, Headline, etc.) would be suitable. The strobilurins must be applied earlier than triazoles in order to prevent the disease from infecting the crop.
If the disease is present, then certainly the triazole chemistry which cures, eradicates, and prevents fungal diseases, (Caramba, Tilt, PropiMax, Bumper, Proline, Folicur, Prosaro, etc.), would be needed if stripe rust has been detected in a field – a mixture of triazole and strobilurin modes of action would also be an excellent program. There are several combination products containingboth triazole and strobilurin modes of action on the market (Twinline, Quilt, Stratego, etc.).
Helena’s tri-active defense fungicide is named AVARIS.
The active ingredients in AVARIS––azoxystrobin and propiconazole––control diseases systemically and through direct contact.
AVARIS has a built-in adjuvant system that improves absorption and coverage of the active ingredients. This co-formulated adjuvant can increase the biological activity of both active ingredients.
In addition to the two modes of action, the activator adjuvant in AVARIS performs the following functions:
→Improves spreading and wetting
→Reduces spray deposit evaporation
→Increases spray deposit adhesion
→Reduces the potential for active ingredient wash-off due to rain or irrigation
→Increases the degree and/or rate that the active ingredients are absorbed
If an additional application of nitrogen is needed for grain fill, AVARIS makes a great tank mix partner with CoRoN 25-0-0-0.5B
For more information, contact you nearest dealer, or Helena representative.
