The Sago Palm (Cycas revoluta) is part of the Cycad family. The Sagos are slow growers taking years to mature.
Cycads are tough and primitive and have been around since the Triassic and Jurassic era. They may be tough, but protecting your cycad plants from the Sago Palm scale is still essential.
It is a popular houseplant and a bold outdoor accent in warmer regions. The sago palm requires plenty of sunlight but prefers part-shade in hotter climates. They do well in areas with partial shade and require regular amounts of water.
Although the sago palm will tolerate partial shade as well, a plant that is growing outside in full sun usually does better and develops faster than indoor plants.
Large specimens of Sago Palms have thick trunks about two feet in diameter and can grow up to ten feet high.
The dark green, spiny leaves can grow about four feet long. Cycad palm trees can have multiple trunk heads, each sprouting multiple sets of leaves.
What Are Sago Palm Scale Pests?
When hearing the word “scale,” someone might think of scales on reptiles. It is not that far off for comparison. Cycad scales grow under a wax covering resembling reptilian scales.
There are many species of plant-scale insects. The most common scale insects that infect the Sago Palm are the following:
- Cycad aulacaspis yasumatsui, or Asian cycad scale
- Pseudaulacaspis cockerelli, or false oleander scale
The Asian scale feeds on the bottom of the fronds. The false oleander scale feeds on the tops of fronds.
These insects are flat and oval and are commonly tan, white, or brown. Scale insects are tiny, as tiny as a pinhead. There are two categories of scales, soft and armored.
Soft scales look like soft, white, powdery dots. Armored scales appear as hard, dark dots. Cycad aulacaspis scale will cover the entire plant stems, trunks, and foliage over time.
The eggs hatch under these “dots” and become larvae or crawlers.
According to Diseases & Pests of Ornamental Plants 10 scale insect species attack Cycas including Black, California red, chaff, Florida red, green shield, hemispherical, oleander, pineapple, purple and soft.
Common problems with sago palm plants include sago palm yellowing, scale, aphids mealybugs, and root rot or crown rot.
Root rot of Sago palm diseases includes Phytophthora fungi. It invades the roots and root crowns of the female plant, causing root rot. Root rot results in leaf wilt, discoloration, and leaf drop.
Related: Why Is My Sago Palm Yellowing?
What Damage Does Sago Palm White Scale Cause?
Scale insects, specifically the crawlers, suck sap from the Sago Palm. As the crawlers feed on the sap of Cycas revoluta, it excretes a sticky substance called honeydew.
This honeydew attracts ants, flies, and other insects.
Honeydew also traps fungus spores. The honeydew leads to sooty mold, which looks like black soot and prevents light from getting through to the new leaves.
While scale insect pests are incredibly tiny, the “scales” are easy to see.
Check for white or black dots or scales on the tops and bottoms of your Sago Palm. On heavily-infested Sago Palms, the leaves will look white.
Check to see if the scales are alive by scraping them. If the scales are dead, they will be dry and powdery. If the scales are moist and squishy, they are active.
Overwatering of Sago Palms
Most plants at garden stores receive the same care, including watering and light, regardless of their species. Sago palms have some drought tolerance, but they prefer a moderate amount of moisture in the soil.
Unfortunately, this approach doesn’t work well for Sago Palms, which can’t tolerate overwatering.
To combat overwatering problems, ensure your sago palms have good drainage and never leave yours in standing water, as too much will result in root rot, of which yellowing leaves are a tell-tale sign.
Related: Planting and Growing Sago Palm Seed
Cycad Scale Treatment: How To Control Sago Palm White Scale?
Scale can devastate Sago Palms. Even though they are quite hardy, they still require some extra care when it comes to certain diseases.
Luckily, getting rid of the scale insects is easy to do naturally or with chemicals. Always read the label directions before applying any chemical.
Be sure to plant only in well-draining soil in a location with adequate light and in containers with sufficient drainage holes.
If you must relocate your sago palm, the best time to do it is in winter or early spring,
Natural Treatments and Methods To Get Rid of Scale On Sago Palm
If your Sago suffers from scale, getting rid of them naturally takes patience.
It’s important to act quickly if you notice signs of fungal disease, particularly if you have other cycads or true palms growing in the area, to avoid spreading throughout your yard.
Fertilizing
The most common deficiencies in sago palms are nitrogen, magnesium, and potassium. Yellow, frizzled, or zigzag new growth is cause for concern and can be a symptom of disease, insects, or nutrient deficiency.
This usually affects older leaves first and will start at the tips. Fertilize once in the spring and once in the summer with a general-purpose fertilizer.
During the active growing season (when days are long and temps are warm) fertilize monthly with a well-balanced palm fertilizer.
Pruning
The first natural method for ridding scale is to prune your Sago Palm. Heavily infested fronds can be pruned, placed in a sealed bag, and disposed of away from male plants. Prune any sick-looking fronds too.
This plant grows best in a soil-based potting mix amended with sand and peat moss.
When transplanting, clean the roots of the plant and keep the root system intact. Prune any blackened or rotten roots, spread out a heavily tangled root system, and mix in some well-rotted organic fertilizer.
Scraping
If the scale found is not too much, you can scrape it off with a fingernail, credit card, or dull object. Note that you might need other methods to prevent the scale infestation from returning.
Isopropyl Alcohol
Use a cotton ball soaked in isopropyl alcohol to dab the pests. If you can, scrape the scale off with the cotton ball.
This will disintegrate the scale and any honeydew leftover. Do this method every two to three days to ensure that the scale is gone permanently.
Neem Oil
Another method is to use neem pesticide oil. Spray your Sago Palm leaves, top and bottom, and all parts of the plant with the neem oil. Mix water and neem that contains azadirachtin, which slowly kills scales and leaves a protective coat on the Sago Palm.
Neem can also be used as a drench.
Details On: How To Mix Neem Oil As A Soil Drench
NOTE: It is recommended when spraying sago palms to spray in the early morning when the temperatures are cooler.
Other options include applying a horticultural oil spray, ultra-fine oil, or SunSpray oil)
Insecticidal Soap
Try an insecticidal soap on your Sago Palm tree. These soaps work by clogging the respiratory spores on the scale of insects, causing them to suffocate.
Most insecticide soaps are organic and won’t damage the Sago Palm. Be sure to wash the soap off between applications not to block the pores on the Sago Palm.
Use insecticidal soap every three days to ensure the scale is gone.
Be sure to research insecticidal soap to make sure it contains only organic ingredients and won’t harm your plant, animals, or humans.
Natural Predators
For a light, infestation introduces natural predators (biological control) such as ladybugs and parasitic wasps into the garden.
Chemical Methods to Get Rid of Scale
Get rid of scales using systemic insecticides and fungicides. A systemic plant insecticide is absorbed through the trunk or root and translocated to other plant parts. Be sure to follow the instructions for proper use.
Horticultural oil is also a suitable chemical method for getting rid of the scale.
The application of horticultural sprays can kill the scale at any life stage and work by blocking respiratory spores on the scale.
If you have ruled out scale and mealybugs, yellowing in younger leaves may be caused by a lack of manganese in the soil. This sago palm is suffering from a classic case of manganese deficiency.
Magnesium deficiency can cause color changes in sago palm leaves so it’s worth picking up a slow-release fertilizer to keep fronds green.
Applying manganese sulfate powder to the soil two to three times per year will correct the problem.
Also, manganese tends to be leached from the soil when the pH is below 5.5. Soil pH and nutrient testing are useful to determine if soils are nutrient deficient.
NOTE: Use these plant scale controls on King Sago – Cycas circinalis.