What Causes Scab on Apricots? Detailed Explanation of Prevention and Control Methods
Peach scab on apricots comes from the fungus Cladosporium carpophilum. It also affects nectarines, plums and peaches. Most apricots with peach scab are grown in home orchards, because commercial growers take preventive measures to prevent it.
Apricots and Peach Scab
Anyone who wants sweet, juicy apricots in their home orchard needs to know about peach scab on apricots. This fungal disease is also called “freckles” because small spots appear on the fruit.
After a warm, wet spring, you will often find peach scab on apricots. The fungus produces lesions on young twigs where spores overwinter. As the weather warms, these spores cause spring infections. They grow fastest at temperatures of about 65 to 75 degrees Fahrenheit (18-24 degrees Celsius).
However, you will not necessarily see symptoms immediately after infection. They may appear after 70 days. Still, you can and should start apricot scab treatment earlier.
How to Stop Scab on Apricots
Treating apricot scab begins first with choosing the planting site for apricots and how to care for them. Perhaps the most important thing to remember is to keep apricots and other susceptible trees out of low-lying sites with poor air and soil drainage.
Another good preventive measure against apricot scab is to prune the trees carefully to open up the center. If you use the open-center pruning system, it provides good air circulation within the canopy, which slows or stops fungal activity.
Do not spend too much time looking for scab-resistant apricot varieties. Most experts believe that all cultivated varieties are susceptible to this fungal disease. If you need further apricot scab treatment, look to fungicides.
Fungicides are an important weapon in treating apricot scab. You need to find a fungicide recommended for this disease, then spray according to the label instructions. Usually, you need to spray once every two weeks from petal fall until 40 days before harvest. The most critical spraying time when treating apricot scab is from shuck split to five weeks after bloom.
