How do scale infestations happen?
Last year, I purchased a Nepenthes talangensis x sibuyanensis at the Bay Area Carnivorous Plant Society Show and Sale (totally recommend going – it’s an excellent event that falls on June 3rd, this year) and introduced it into my Nepenthes terrarium without a full inspection.
Regret.
Scale is one of the few pests that attack Nepenthes and it hitched a ride on that new plant. The infestation was insidious. It went from “oh, hey, what’s that?” to “oh crap, oh crap, oh crap” in a few week’s time – a single summer vacation, to be exact.
Learn from my mistake and closely inspect new plants before introducing them into your terrarium/greenhouse/shared water tray. I would go as far as to suggest quarantining new plants for 1-1.5 months in a separate growing environment to make sure no uninvited pests are present. Why 1-1.5 months? Because plants can be wiped down, and made to look “clean” for the sake of selling them at shows. It may take this long for scale to reproduce to the point that it’s noticeable. Furthermore, plants treated with a systemic pesticide may, in fact, be clean at time of sale, but if only 99% of scale was killed by the pesticide, you could have a re-infestation.
What are scale and how do you identify them?
Scale are a parasitic pest that latches onto the surface of a plant and taps into the vascular system to suck out sap. There are about 8,000 described species of scale, but the variety I have the joy of dealing with appear as small, white and beige nodes. Only the females feed, they are immobile once they start feeding, and they form waxy coatings as a means of protection. Because they don’t move far before munching on your plant, they tend to form colonies, or clusters that will almost look like white freckles across the plant.
For those curious – males are usually winged and only hang around for a day or two to reproduce before dying. Mercifully, they do not feed on your plants.
How to treat scale infestations
Your weapons, should you choose to do battle, will be a systemic pesticide and a spray bottle that you will use to apply said pesticide. While contact pesticides require direct contact with a scale infestation to kill it, systemic pesticides work by being absorbed into the tissues of your plants, and poisoning scale as they feast. Systemics remain in plant tissues from one week to about two months and can kill even future generations of the pest. I would recommend 3-4 applications of a systemic pesticide spaced 1-1.5 weeks apart. This will ensure that you get thorough coverage, and kill even the offspring that may have survived early rounds of insecticide.
Below, I will recommend a few products that I’ve used and had good results with.
Systemic Pesticides for Scale Infestations
I’ve had good results with the systemic pesticide. You will dilute this with water, so one bottle of this size should go a long way, unless you’re hosing down a medium-to-large greenhouse. Scale are a robust pest, so make sure to spray at least 3 times waiting 7 to 10 days between each application. Bonus: It also happens to be good at handling aphids, thrips, leafminers, mealybugs, caterpillars, and whiteflies if any of those should be a problem for your plants.
You can pick this up on Amazon by clicking here.
A Pressurized, Chemical Resistant Spray Bottle
This 2 liter Solo sprayer is a great, highly-rated pressurized spray bottle on Amazon. Mine is a slightly different model, but this one is less expensive and can be Prime’d for faster shipping. Even if you don’t go with this exact model, look for something that is chemical resistant, can be pumped to a desired pressure, and has a nozzle that can be adjusted for spray or mist. You may use this for other purposes in the future, so misting is good to coat plants while a spray setting is good to hit hard-to-reach places.
You can pick this up on Amazon, here.
Now what?
After the first week, you will notice a marked slow down or complete stop to new scale colonies. At this point, feel free to wipe down your plant’s leaves of the old, now dead, scale. Reapply the systemic pesticide per prior instructions, and keep an eye out for any new buggers you see pop up. After a few applications, they should completely cease to exist.
Have you had a scale problem? Let us know in the comments, below, and how you dealt with it!
What dilution with water and Bonide should I use to treat scale on Nepenthes. Don’t want to overmedicate and harm my beautiful Predator. Thanks
Howdy Rich. As with many drugs, there is a minimum effective dose on the pesticide. I’ve used Bonide at full recommended strength (follow the instructions on the bottle) on my Nepenthes without issue. If you’re concerned, you can always start with a 50% dilution to the manufacturer recommendation and work your way up from there – just don’t expect the scale to be completely wiped out at this dilution.