Maintaining healthy pecan trees requires vigilance, proactive management, and an understanding of common diseases that can impact their growth and productivity. By implementing cultural practices, selecting disease-resistant cultivars, and incorporating timely fungicide applications when necessary, growers and homeowners can mitigate the impact of diseases like pecan scab, bacterial leaf scorch, and powdery mildew.

Regular monitoring of trees for early signs of disease, coupled with prompt intervention, is essential for preserving the health and longevity of pecan orchards and individual specimens. Additionally, staying informed about emerging diseases and advancements in disease management techniques can further enhance the resilience of pecan trees against the challenges posed by pathogens. Through careful attention and sound management practices, pecan enthusiasts can continue to enjoy the beauty and bounty of these iconic trees for generations to come.

Pecan trees, cherished for their delicious nuts and their ornamental value, are susceptible to various diseases that can threaten their health and productivity. Whether you're a commercial grower or a homeowner with a pecan tree in your yard, understanding common pecan diseases is crucial for maintaining tree health and maximizing nut production. In this article, we'll explore some of the most prevalent diseases affecting pecan trees, their symptoms, prevention strategies, and treatment options.

1. Pecan Scab (Fusicladium effusum)

Pecan scab is arguably the most economically significant disease affecting pecan trees, particularly in regions with high humidity and rainfall. It is caused by the fungus Fusicladium effusum. Scab affects leaves, shoots, nuts, and shucks, leading to reduced nut quality and yield.

Symptoms: Pecan scab appears as dark, olive-green to black lesions on leaves, husks, and shucks. These lesions may coalesce, causing defoliation and premature nut drop. Infected nuts often exhibit dark, sunken spots, rendering them unmarketable.

Prevention and Treatment: Cultural practices such as proper tree spacing, adequate air circulation, and timely removal of infected plant debris can help mitigate pecan scab. Fungicide applications, especially during periods of rapid shoot and nut growth, are crucial for managing scab. Fungicides containing active ingredients like azoxystrobin and propiconazole are commonly used for scab control.

2. Pecan Bacterial Leaf Scorch (Xylella fastidiosa)

Pecan bacterial leaf scorch is caused by the bacterium Xylella fastidiosa and is prevalent in the southeastern United States. It affects water-conducting tissues, leading to leaf scorching and decline in tree health.

Symptoms: Infected leaves exhibit marginal necrosis or browning, which gradually progresses inward, giving the appearance of leaf scorch. Trees may also display wilting, leaf drop, and stunted growth. In advanced stages, bacterial leaf scorch can lead to tree death.

Prevention and Treatment: Management of pecan bacterial leaf scorch involves selecting disease-resistant cultivars and employing cultural practices that promote tree vigor. Removing and destroying infected trees can prevent the spread of the disease to healthy specimens. Unfortunately, there are limited treatment options once trees are infected.

3. Pecan Powdery Mildew (Phyllactinia corylea)

Pecan powdery mildew is a fungal disease that thrives in humid conditions. It primarily affects foliage, reducing photosynthetic capacity and weakening the tree over time.

Symptoms: Powdery mildew appears as a white to grayish powdery growth on the upper surface of leaves. Infected leaves may curl, distort, and prematurely drop. Severe infections can lead to defoliation and reduced nut production.

Prevention and Treatment: Proper tree spacing, pruning to improve air circulation, and avoiding excessive nitrogen fertilization can help minimize powdery mildew incidence. Fungicides containing active ingredients like triadimefon and myclobutanil can be applied preventively to manage the disease.