Citrus Gummosis
Gummosis is the most prevalent fungal disease in citrus groves. It looks like wonderful gum. This is why the majority of people disregard it and do not consider it a disease. Gummosis diseases are caused by Phytophthora fungus. Phytophthora fungus, the causative agent of citrus gummosis, is present in virtually all citrus gardens. Under conditions of high humidity, the fungus produces vast quantities of bacteria, which are then deposited on the tree trunks. The Phytophthora group that causes gummosis grows rapidly in moist, humid circumstances. Warm weather slows the spread of gummosis and aids in the drying and healing of lesions.
Symptoms of Gummosis Disease
Sap seeping from small cracks in the infected bark, giving the tree a bleeding appearance, is an early sign of citrus gummosis. Fruit will exhibit symptoms if the disease is severe. It is possible for a population to decline over several years or rapidly within a single year, especially under conditions favorable to disease development. It may also be observed if there was an abundance of floral initiation. This will ultimately result in the demise of the affected plant.
Citrus Gummosis Disease Background
This condition is also known as citrus gumming disease. It is brought on by a fungus. Due to extended durations of rainy and humid circumstances, soil and nursery plants may become infected. This disease is prevalent in mandarins, sweet oranges, lemons, and other citrus fruits. Citrus gummosis is one of the principal diseases that lead to the deterioration of citrus.
Disease Cycle of Gummosis Disease
Phytophthora is a globally prevalent water mold (Class Oomycetes, once a fungus-like protist). Under suitable conditions (high humidity and warmth), it produces a significant quantity of water-swimming zoospores that are motile. These zoospores are infectious agents that can be delivered to the roots by rain or irrigation. When zoospores come into contact with roots, they encyst, germinate, and enter the root tip, causing the entire rootlet to rot.
Footrot and citrus gummosis are caused when zoospores splash onto a wound or bark break at the trunk’s base. In addition, there is a relationship between Phytophthora root rot and the presence of citrus root weevils, including Diaprepes abditus, that cause root damage. The susceptibility of rootstock depends on the Phytophthora species present and favorable soil, water, and environmental conditions.
Citrus Gummosis is caused by
Phytophthora fungus are prevalent in the vast majority of citrus groves. Under wet conditions, fungus create an abundance of motile zoospores, which are splattered onto tree trunks. The gummosis-causing Phytophthora species grows rapidly in damp, chilly circumstances. The heat of summer reduces the spread of disease and aids in the drying and healing of sores. Through Phytophthora-caused lesions, secondary infections commonly arise.
Gummosis of Citrus Management & Treatment
- Always maintain a tidy orchard. Remove unproductive, dry, and insect disease-infested branches.
- The unproductive branches are rapidly ascending. Use Bordeaux-pest 10% on pruning wounds and the main trunk from the ground up to approximately one meter in height.
- After harvest, apply 1% Bordeaux mixture to the entire plant and repeat during the fruit set. Check the orchard frequently.
- Apply Bordeaux-pest 10% immediately if the bark is cracked or has mechanical damage. Similarly, if gum discharge is on any area of the tree, remove it and apply Bordeaux pest as described previously.
- The late stages of Phytophthora citrus gummosis are identifiable, although the early signs are frequently difficult to identify. To save a tree, however, early discovery and rapid management activities are required. If 50% or more of a mature tree’s trunk or crown region is girdled, it may be more cost-effective to replace the tree than to attempt to treat the infection.
- Before planting new trees while establishing a new orchard, thoroughly inspect the lower trunk and rootstock for signs of citrus gummosis. When trees are wrapped in burlap, a representative sample (at least 10 percent of the trees) should be opened and inspected. Fumigation may be useful when planting or replanting in Phytophthora-infected soil, or when a susceptible rootstock must be used.
Gummosis of Citrus Chemical Control
Citrus Gummosis is a highly destructive disease that causes substantial losses in citrus groves. On two sweet orange cultivars, Musambi and Red blood, five fungicides, namely Aliette, Ridomil gold, Topsin-M, Score-250 EC, and Benlate, were evaluated for their efficacy against the disease. Aliette and Ridomil gold were shown to be the most efficient fungicides against illness. Other fungicides were not as effective at controlling the disease.
Cultural Control of Citrus Gummosis
- Remove the diseased bark as well as a buffer strip of healthy, light brown to greenish bark at the infection’s edges.
- Permit the affected area to dry out. You can also softly scrape the diseased bark to determine the lesion’s perimeter, and then use a propane torch to burn the lesion and a 1-inch (2.5-cm) zone around it.
- Repeat if necessary after a few months of repeated inspections.
Gummosis In Citrus
Gummosis is a common problem in citrus trees, particularly in oranges, lemons, and other citrus varieties. It is a condition characterized by the oozing or exuding of gummy substances from the trunk, branches, or fruit of the citrus tree.
Infection by Pathogens: Fungal and bacterial pathogens can infect citrus trees and cause gummosis. The pathogens often enter the tree through wounds or injuries in the bark or branches. Common pathogens associated with gummosis in citrus include Phytophthora species, Diplodia natalensis, and Xanthomonas axonopodis.
Environmental Stress: Environmental stress factors, such as extreme temperatures, drought, and excessive moisture, can weaken citrus trees and make them more susceptible to gummosis. These stressors can also lead to physical damage to the tree’s bark and tissues.
Mechanical Damage: Physical injuries or mechanical damage to the tree, such as from lawnmowers or pruning tools, can create entry points for pathogens and contribute to gummosis.
Insect Infestations: Some citrus pests, like the Asian citrus psyllid, can transmit disease-causing pathogens to citrus trees, which can result in gummosis.