Yucca plants are a member of the agave family have over 40 notable species. They are tough, hardy perennials featuring a spiral rosette of sword-shaped leaves and large spikes of white flowers. Generally, the Yucca genus is easy to grow and care for. However, they are susceptible to problems like diseases, and pests.
Yucca gloriosa Variegata – Adams Needle
The most common pests that disrupt the healthy growth of Yucca plants are scales, yucca weevil, mealybugs, and mites. While common fungal and bacterial diseases that affect yucca plants are brown spots, grey leaf spots, Fusarium stem rot, sclerotia, necrotic tips, southern blight, etc. These pests and diseases may be invited to the plants for various reasons including overwatering, insufficient light, transplant stress, temperature stress.
Let’s discuss the common problem in detail starting with the pests.
IN THIS ARTICLE
Pests That Affect Yucca Plants
Yucca Weevil
Sycophorus yucca commonly called yucca weevil is a black beetle that is half an inch long with an elongated snout. The larvae are white grubs that girdle into the leaves, base of flower stalks, and the heart of the yucca plant. They destroy the plant by creating feeding holes in the foliage and other parts of the plants that leave the plant vulnerable to other infections.
The only solution to the infestation of the yucca weevil is to remove and destroy the affected yucca plants as soon as possible.
Mealybugs eating your Yucca
These pests look like masses of cotton stuck in the leaf axis and under the leaves. They attack yucca plants in clusters and cause slow growth and eventual dieback of the entire plant. The presence of mealybugs on your yucca plant will attract ants because they excrete sweet honeydew.
The infestation of mealy bugs is often controlled by natural predators but you can also spray thoroughly spray your plants with insecticidal soap or narrow-range oil.
Yucca Mites
These pests are technically not insects but are arachnids. They look like tiny dots but are two-spotted mites that feed on the yucca plant sap and leave a stippling on the plant leaves that eventually turn grey. Some sort of webbing occurs in cases of serious infestation and can be controlled with regular misting or washing of the plant.
Diseases That Affect Yucca Plants
Fusarium Stem Rot affecting Yucca
The yucca plant stem becomes soft and begins to rot and this will also affect the leaves. The plant develops red perithecia and ochre-coloured groups of conidia around the infected areas. It is a fungal infection yet no existing fungicides have been effective in controlling this disease.
You can avoid the development of this disease by ensuring the planting soil is pathogen-free and using disinfected gardening equipment.
Gray Leaf Spots on Yuccas
It is a fungal infection caused by Cytosporina sp and mostly affects the Spanish Bayonet yucca plant. It affects the leaves of the yucca at the edges and tips. They begin to turn grey with brown lesions. These lesions can be light or dark coloured but it causes eventual death of the leaves. Prevent it by avoiding overhead watering and maintaining a dry environment for your yucca plant. It can be controlled by cutting off infected leaves and spraying the plant with pesticides.
Other issues with yucca plants include:
- Root rot: This will cause your yucca plant to have a soft trunk, drooping branches, wilted leaves that turn black before eventually falling off.
- Dark spots: This indicates fungal spots.
- Soft trunks: It is caused as a result of overwatering your yucca plant.
- Brown leaves: When yucca plants don’t get enough light, leaves fade to brown.
- Limp leaves: This is caused by the amount of sunlight or water that your yucca gets.
FAQ
Why is my yucca plant dying?
Several problems may cause your yucca plant to begin dying. Some common causes are overwatering, over fertilising, insufficient light, temperature stress, insufficient light, excessive exposure to sunlight, pests and diseases, etc.
Why do my yucca plants have yellow leaves?
The most common cause of yellow leaves on yucca plants is overwatering. Other causes may include excessive exposure to sunlight and pest such as spider mites.
What happens if you cut off the top a yucca?
Cutting off the top of a yucca plant will stop the plant growth. The plant will seize to grow in height and will not produce new leaves rather the old leaves will continue to go through photosynthesis before eventually dying off.
