Palm lilies are actually very robust plants. However, care mistakes make the plant more susceptible to diseases and pests.
The yucca is an undemanding plant and resistant to most diseases. However, a common appearance is yellow or brown leaves. This can not only be due to a wrong location, but also to a fungal infestation.
Although yucca are mostly resistant to pests, scale insects and leaf beetles, also known as lily beetles, sometimes appear. It is important that you take quick control measures now to save the plant from dying.
An overview of possible diseases and pests
Discolored leaves on the Yucca
The palm lily originally comes from very dry and warm regions. In the garden, it needs a bright to full sun and wind-protected location. The soil should be well drained. You only have to water the plant outdoors if it is hot and dry for a long time.
It is different with potted plants. A regular water supply is important here, but not too much. Always wait until the top layer of soil has dried. Good drainage in the pot prevents waterlogging.
Place the yucca in the tub in a bright and sunny place. In the shade, the leaves wither and turn yellow to brown. If yellow or brown leaves do appear: find a better location for the container plant or put the plant in a sunnier place in the garden. Remove the discolored leaves, the plant is usually fit again quickly.
Leaf spot disease
Leaf spot disease is caused by a fungus. Mistakes in care and wrong locations favor the disease. You can recognize the infestation by the initially small spots and deposits on the leaves. The spots are round or irregular, after a while the leaf tissue crumbles. Remove the affected leaves and spray the plant with a fungicide.
Root Rot
If the palm lily is permanently too damp or gets too much water, theroots rot. You can recognize the disease by stunted growth and a musty odor near the ground. Sometimes there is also a fungus-like rash on the leaves. Stop watering as an immediate measure. Sometimes that is enough and the plant will recover. If not, you have to dig up the yucca or take it out of the bucket.
In the next step, replace the soil and remove the affected root parts. The new substrate should be well drained. A mixture of soil and sand is ideal. As a preventive measure, you can mix an appropriate plant protection product into the substrate to prevent root rot.
scale insects
You can recognize scale insects and lily beetles with the naked eye on the leaves of the yucca. Scale insects grow up to two millimeters long, eat holes in the leaves and leave sticky marks.
Fight scale insects by brushing, wiping and showering the leaves. Lacewings and parasitic wasps are natural enemies. Oil-based preparations are also helpful.
Lily Chicken
Lily beetles often appear as early as spring. It is a leaf beetle, red in color and up to eight millimeters long. Not only the beetles are voracious, but also the larvae. If the plant is affected, quick action is called for because the beetles are multiplying massively. They often sit on the underside of the leaves and radically eat the leaves away.
You can remove the lily beetle by regularly checking, collecting bugs and rinsing the plants with cold water. The cold shower also removes eggs that have already been laid.
A thick layer of coffee grounds around the plant will prevent lily beetle from spreading. The shift should be renewed every week. Unfortunately, if these measures are unsuccessful, the only option left is to use insecticides against the leaf beetles.