“Fishhook Barrel Cactus is an extremely easy accent plant to grow in and around the Tucson area. It tolerates most native soils with good drainage, requiring little attention or special care. The Fishhook barrel cactus is tolerant of extreme heat as well as cold. This plant relies on annual rainfall, making it a good choice for xeriscape landscapes.”
“The Fishhook Barrel Cactus is recognized by the curved and hooked central spine and by the large, ribbed, “barrel-shaped” body. Bright orange to yellow colored flowers will appear in September and October in a ring around the apex of this cactus. It produces yellow, pineapple-shaped fruit that is edible. The Fish-hook barrel is the most common barrel cactus growing in Tucson, AZ. Typically, it grows 3 feet tall and up to 30 inches in diameter. The Fishhook barrel cactus makes a great accent plant for anyone who loves blooming cacti.”
What Is Pythium Rot in Barrel Cactus?
Pythium is an invasive fungus that attacks many types of plants, including not only cacti but also roses, mosses, and wisteria. It thrives in moist soil and when left untreated can quickly kill a plant. The first sign of pythium is black spots on the plant’s leaves or branches. These spots may then become brown, black, or grey and begin to produce spores. If you observe these signs on your fishhook barrel cactus, it is best to remove the affected area right away to prevent the infection from spreading.
“Pythium, Phytophthora, and Armillaria species are important causes of root rots.”
Fishhook Barrel cactus rot usually occurs when a plant is too deep in the soil (more than halfway) or when its roots have been damaged. This makes it important to use sterile soil with no fertilizers
“Black leg of geranium, is caused by the water mold Pythium, while black leg of crucifers is caused by the fungus Phoma.”
Once the plant has the disease, there is no effective pythium root rot treatment. The cactus is best removed and destroyed. There are, however, preventative treatments for susceptible species.
“Because water is the major limitation for bacteria and most fungi, be careful with irrigation. Overwatering favors water mold species like Phytophthora and Pythium and the root rots they cause. Avoid wetting leaves and stems if possible to prevent foliar diseases. If overhead watering cannot be avoided, at least water during times that will not add hours to the natural nighttime leaf wetness period. Space and prune plants properly to improve air circulation and help the foliage dry quickly.”
The cause of the disease is the soil-borne fungus-like organism. After the roots have been infected, the disease makes to spread through into the cambium, and eventually infects the entire plant.
Although the disease isn’t often present in commercial soil It is possible to spread via contaminated tools, old, dirty pots; or from activities of animals. In fact, even the wear of dirty gardening gloves can introduce the pathogen to clean, sterile soil.
Pythium Rot Symptoms
Pythium disease is almost impossible to detect until it is too late. This is because it starts in the soil at the plant’s roots. If you were to remove the plant, you could see that the roots are mushy, discolored, and rotten. What exactly causes this disease? The culprit is actually a tiny organism called Pythium which lives in soil and water. It attacks the roots of plants by entering at the growing tip or through wounds. Once inside, it spreads rapidly throughout the root tissue, causing it to rot. When a plant becomes infected with Pythium, its leaves begin to curl and turn brown while its stem will wilt suddenly and fall over.
The disease advances upwards with soft spots appearing and eventually, the whole stem becomes yellow. If you keep an eye on the base of the plant for signs of yellowing near the soil line, you may be able to keep it. When the stem is soft, however, it is lost. Pythium rot that occurs in barrel cactus is typically fatal.
“Some of their hooked spines are strong enough to have been used as actual fishing hooks by indigenous and local peoples throughout the Americas.”