IN YOUR ORCHARD
TIME TO CONSIDER Can you believe it’s already 2024 ? It might be hard to believe, but there is no time to look in the rearview mirror. 2024 is here and it’s time to start looking forward to the year to come and how you can be prepared. It seems like we are having a warmer winter, which can be related to the Northern Hemisphere experiencing an El Niño year. Barring any significant changes, this warm weather may lead to bloom being right around the corner, which provides a good chance that we will experience some rain during that time. Growers all know what warm temperatures and wet weather bring to almond orchards: disease. First, let’s dive into a few of those bloom-time diseases and what can be done to prevent them. Second, we’ll look at the importance of bees during pollination. Finally, let’s talk about the importance of a budget and how to plan for those costs. Bloom-time Diseases Being prepared for any weather event is critical to the success of a fungicide application. The first spring disease that usually comes to mind is Brown Rot. The disease doesn’t need much moisture to be a problem. Brown Rot can be present with little to no rain because of the natural moisture present in the flower itself; even the morning dew can set us up for a problem. The next disease that I’ve seen grow in prevalence in the Central Valley is Jacket Rot/Green Fruit Rot . This disease, like many others, must have the right conditions to be present. Jacket Rot usually appears later in bloom when the fungus effects the dropping petals, jackets, or other parts of the flower. Because of the moisture, the flower material sticks to the young almonds. Jacket Rot is most prominent in dense clusters of almonds because the falling plant material becomes trapped in the almond cluster, leading to the infection of the whole cluster. Shot Hole is another common springtime disease but has become less of an issue over the years. This disease is usually easy to discover, as it develops small reddish spots on the leaves, typically leaving a dark spot in the center. These lesions can show
up on other parts of the plant, but are most commonly found on the leaves. Dr. Jim Adaskaveg with UC Riverside says shot hole “hasn’t been much of an issue over the past decade or longer, however, in large part because fungicides used to control other diseases have kept it at bay.” The last disease I’ll touch on is Anthracnose . Like the diseases mentioned earlier, anthracnose is dependent on environmental conditions. Heavy moisture or rain along with warmer temperatures will lead to the development of the disease. Symptoms appear as blossom blight, fruit infections, and spur and limb dieback. Anthracnose is not a disease you want getting a foothold in your orchard. The disease can have a multiple-year effect because of the infection to spurs and limbs. Growers may have to prune out the infection and use a strong fungicide program to eradicate it. Preventing Bloom-time Diseases We’ve identified the diseases that cause growers so many headaches during bloom, but how do we control them ? There are several fungicides that you can choose from. It is vital to select the correct fungicide for the disease you are trying to prevent along with the correct timing to apply the fungicide. In Figure 1 , you will find a chart of different diseases and an effective application time. The chart is on a 0-3 scale, with 0 being ineffective and 3 being most effective. This can help you target past disease issues. For
Figure 1: UC Davis IPM
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ALMOND FACTS
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