Western Farm Press Logo

Control Alternaria in almond orchards this summer

Learn how growers can identify Alternaria, control the disease with Merivon fungicide and implement resistance management best practices.

3 Min Read

With California exporting a record two billion pounds of almonds, it’s more important than ever for almond growers to achieve high levels of quality and production.

In order to protect their investment, almond growers should be aware of the threat that diseases like Alternaria pose to their crop.

Risks of trees left unchecked

If Alternaria is left uncontrolled, the resulting defoliation of trees can lead to immediate yield loss in the current year and compounded productivity losses in the years that follow.

Significant rainfall this spring has set the stage for early Alternaria development. The later it gets in the season, the threat of this disease continues, due to extreme humidity brought on by irrigation systems running more consistently, along with a thick tree canopy.

“Heat and humidity help to breed the disease. Spring rains have brought the humidity, which is why it is so important to consider a preventative fungicide before warm, conducive conditions occur,” said Leigh Ann Harrison, BASF Technical Service Representative. “Having a disease control plan that includes fungicide sprays to control Alternaria is crucial, especially if your orchard has a history of Alternaria pressure.”

The signs of the disease are irregular-shaped lesions that develop black rings of spores inside the lesion.

In severe cases, the disease can defoliate trees rapidly, sometimes leading to complete defoliation by early summer.

Gather information before spraying

Before selecting a fungicide for summer applications for Alternaria, almond growers should monitor the weather in April or May for conditions that can be conducive to disease development. There is a higher likelihood of Alternaria infection with temperatures ranging between 60 and 85 degrees Fahrenheit, particularly in orchards with stagnant air or little wind movement.

If weather conditions are conducive to disease development, a preventative application is ideal, since Alternaria is difficult to control once symptoms start to develop.

Selecting an appropriate fungicide

A key step in managing Alternaria is selecting the right fungicide as part of a planned program that rotates fungicide modes of action. As a part of this disease control program, growers should invest in a preventative application of fungicide that controls a wide spectrum of diseases early in the season. By doing this, growers can set a strong foundation for the year.

“Growers should not only spray if the disease is present, but take preventative measures to keep their crops healthy,” said Harrison. “We recommend Merivon® fungicide for the Plant Health benefits it provides to the crop, including stress mitigation against heat and drought, in addition to control of diseases like Alternaria.”

Merivon fungicide has consistently been a top performer against Alternaria in University of California trials for over 7 years. Merivon provides broad-spectrum disease protection so that almond growers can control a variety of diseases that might impact their orchards.

Resistance management

As with any product, growers should keep in mind best practices for resistance management. Strategies for effective resistance management include rotating different modes of action within a spray program, adhering to the label and achieving thorough coverage with sprays.

“Growers should be prepared to protect their investment in almond orchards by taking preventative measures to control it and following best practices for resistance management,” said Harrison.

Visit GrowSmartAlmonds.com to find out more about how Merivon fungicide works to control Alternaria.

Always read and follow label directions.

Merivon fungicide is a registered trademark of BASF. All rights reserved.
© 2019 BASF Corporation

Subscribe to receive top agriculture news
Be informed daily with these free e-newsletters

You May Also Like