I've recently received calls about sago palms and "some white stuff" on them. Others have described it as a "snow-like dusting" or even "a white fungus like film." In most cases, the problem is an insect called Cycad Scale.
Cycad is the scientific name for sago palms. Tiny and white, cycad scales cover and leech on sago palm fronds. The technical name of this troublesome insect is Cycad aulacaspis scale, which is also known as Asian Cycad Scale.
These insects were inadvertently brought here from Thailand and were first found in Florida in the early 1990s. Recently, they made a devastating impact in the Rio Grande Valley here in Texas.
Cycad scales are easily controlled with insecticidal sprays or a homemade organic scale control. However, the problem is that the average homeowner fails to notice the condition and take the proper course of action before the infestation is beyond repair.
In Texas, cycad scale problems emerged in 2001. I discovered the insects on my sagos last year, and I treated the condition by using Malathion on the entire plant. I haven't seen the problem since.
If you have serious infestation, prune off fronds that are heavily coated with cycad scales. To help prevent re-infestation, dispose cuttings in double-sealed plastic bags. For the earliest onset of these pests, chemical controls like Malathion work wonderfully. Other products for control are Acephate or Carbaryl (Sevin).
Organically, there are two ways to get control. You can use a dormant oil spray in December and January, or you can use our homemade version of scale. The formula listed below came from our friends at Condon Gardens, one of the few, truly organic landscapers in Houston. control.
Mix in a gallon sprayer:
- 1 ounce of Molasses (Medina & GardenVille Molasses are great examples)
- 1 ounce of Garlic Oil (Garlic Barrier is the most widely recognized)
- 1 ounce of Liquid Seaweed (GardenVille Liquid Seaweed is well known)
- Then fill the rest with water.
If you have an inordinate amount of insects, such as aphids or whiteflies, you can also mix in a couple of ounces of liquid Pyrethrum and keep the spray organic, but create an instant "knockdown" of heavy infestations.
J.C. and Carter at Condon Gardens both agreed that if you just use the mixture occasionally, not only do you keep any insects from generating damaging populations but you get some natural disease control on landscapes with the Garlic Oil and Seaweed. If you were wondering about the need for the Agricultural Types of the Garlic and Molasses, the reason is pretty simple: The Agricultural ones haven't been overly processed, and all the natural sugars and microbes etc. are still there and needed in the overall scheme of organic controls.
Obviously, you are not going to find all these products at your average garden center, especially mass merchandisers and big box stores. But there are many independent nurseries and garden centers that carry all of these products. In fact, even if the list below doesn't have any of the noted products on the shelves, they can easily order them in less than one week from the local distributors. These are just a few retailers that I know either carry such products or can get them for you in a matter of days. Again, just ask your local garden retailer if these are products that they can order for you, if you don't see a garden center near you on this list:
- Condon Gardens (Hammerly 2 blocks East of Wirt )
- RCW Nurseries (249 @ Beltway 8)
- Southwest Fertilizer (Bissonet & Renwick)
- Cornelius Nurseries (3 locations)
- ABC Country Store (In Katy, near Katy High School)
- Buchanan's Native Plants (On 11th St. in the Heights)
- Maas Nursery (5511 Toddville Rd. in Seabrook)
Licensed applicators, such as pest control companies or certified landscaping services, can also use products containing dimethoate, pyriproxyfen and dinotefuran.
The best way to prevent cycad scale infestation is to check your sago palms once a week or at least once every two weeks. That way, you can look for anything out of the ordinary and catch these pests in their earliest of stages.