Phytophthora root and crown rot
Phytophthora spp.
Also Known As - Phytophthora crown and spear rot,Phytophthora root rot,Brown rot,Phytophthora gummosis,Root rot,Phytophthora root and crown rot (Red Stele),Red Stele (Phytophthora root and crown rot),Buckeye (Phytophthora root rot),Phytophthora root rot (Buckeye),Collar foot root and crown rot,Damping off and seed rotsWhat is Phytophthora root (Phytophthora ssp)?
Phytophthora root and crown rots are fungal diseases caused by soilborne fungi of the genus Phytophthora. These diseases affect various trees and shrubs in the northeastern region. Commonly infected hosts include rhododendron, andromeda, holly, yew, juniper, beech, dogwood, maple, apple, cherry, peach, and apricot. Infected plants exhibit yellowing, and browning of leaves, and an overall decline in health. The pathogen spreads from the roots to the root crown and lower trunk, leading to root decay, wilting, stunted growth, and, in severe cases, plant death
How does Phytophthora root (Phytophthora ssp) occur?
Crown rot happens when Phytophthora pathogens infect the roots and crown of vulnerable plants. These pathogens release zoospores that can swim in water. When the soil becomes saturated, the zoospores are attracted to plant roots and invade them. They then gradually move upward, infecting the root crown and lower trunk. The fungi target the inner bark, causing the death of inner bark and browning of the outer sapwood layer. This leads to plant decline or death.
Symptoms
1 - Effects on Plants
It impairs the plant's ability to absorb water and nutrients, leading to wilting, stunted growth, and reduced productivity. Severe infections can result in plant death.
2 - Effects on Soil
• It can impact soil health and functionality. The decayed root and crown tissues contribute to organic matter decomposition, affecting nutrient cycling and soil structure. • Additionally, the pathogens can persist in the soil, potentially infecting future plantings and perpetuating the disease cycle.
3 - Effects on the Environment
Crown rot can have environmental consequences. Infected plants may shed leaves or prematurely die, contributing to increased plant debris and organic matter accumulation in the environment. This can impact natural ecosystems and potentially alter nutrient dynamics.
Solutions
1 - Prevention and Cultural Practices
• Good Water Management: Avoid overwatering and ensure proper drainage. • Plant Selection: Choose resistant or tolerant plant varieties. • Site Selection: Plant in well-drained areas, avoiding low-lying or poorly drained spots. • Soil Improvement: Incorporate organic matter to improve soil drainage. • Proper Planting: Follow recommended planting guidelines to avoid burying the root crown. • Sanitation: Remove and destroy infected plant material. • Crop Rotation: Practice rotation in vegetable gardens to reduce pathogen buildup. • Avoid Soil Contamination: Prevent the introduction of contaminated soil, water, or plant material. • Regular Monitoring: Monitor plants for early signs of disease.
2 - Fungicide Application
Metalaxyl/Mefenoxam and Fosetyl-Aluminum Systemic fungicides provide control against Phytophthora species, and Products based on phosphorous acid and Dimethomorph fungicides with protective and curative properties are being used against this fungus. Consult local agricultural resources for specific recommendations and follow label instructions for proper use.
