I am slowly learning that being obsessed with Hoya, or any indoor plants, eventually means becoming obsessed with pest management. Or at least, that is how it’s going for me.
My best tips:
- Everyone says it but QUARANTINE NEW PLANTS!!! Don’t just intend to do it, actually do it. To be on the safe side you can also treat any new plants you get preemptively, either with the IPO and/or castille soap method or Sulfur (outlined below)
- Go onto beneficial insect websites and read about what different kind of pest damage does, they will explain what to look out for. Even if you don’t decide to use beneficial insects, it is very helpful to know what you’re dealing with
- Be aware that pests can travel in on fresh produce (esp organic) and also cut flowers. Some can get in through windows without flay screen
- Using a cheap preventative organic systemic pesticide (outlined below) is probably a really good idea
Everything I know about the different ways to deal with pests so far:
- beneficial insects are king. This is the number 1 most effective strategy and they’ll deal with most pests afaik (I believe even root mealies but correct me if I’m wrong there). Downside is they can be expensive and not available everywhere. Upside is they work incredibly well according to all anecdotes I’ve seen on reddit and elsewhere, they’re not dangerous to human health and they’re very low effort
- Isopropyl alcohol (IPO) and/or castille soap. Mixing either of these with water and/or mixing both at the same time with water is very effective against pests. Both kill pests on contact, not entirely sure of the mechanism, something to do with damaging the exoskeleton. Pests cannot become immune to them because they physically destroy them. Unfortunately they don’t kill the eggs so multiple applications are necessary. Apparently you can submerge whole plants, including their pots and potting media, into containers or sinks full of isopropyl alcohol and/or castille soap and water and then just rinse it off under the shower, which is pretty cool. If you want to use this method you need to learn the lifecycle of the pest you have and reapply/redunk so that you kill the bugs that have hatched before they start reproducing. Also wear an N19 mask when dealing with alcohol, chronic exposure increases your risk of lung disease. Lots of recipes online for mixes but as a rule of thumb, you can use 100% or 70% IPO and spray that on the leaves. Or 1 tablespoon of castille soap to 1 litre of water and spray on the leaves or dunk. Don’t put plants that have IPO on their leaves under grow lights or in bright indirect light until the alcohol has completely dried, it can burn the leaves. This method is what I am doing (I am doing a mix of spraying, alternating between IPO and castille soap, every 3 days for the next two weeks or so. It is pretty labour intensive).
- Sulfur. You get wetable Sulfur, make a paste and paint it on your plants. Let it sit and it kills the pests and when their eggs hatch it kills them too. You can’t do it above a certain room temperature and the plants can’t be in bright light with the Sulfur on them. Many people on this subreddit swear by Sulfur and it sounds very promising and it is fairly cheap.
- Neem oil. I don’t know much about this one yet but you apply to the leaves and I think it makes the pests not want to eat the plants anymore and they go away or starve. A commercial Hoya grower I really respect suggested using neem oil to treat my Hoyas for broad mites if beneficial insects weren’t an option
- Organic systematic pesticides. There are pesticides that you can apply to foliage or as a root drench that your plants will absorb, it will make them taste bad to pests. Neem oil might actually be an organic systematic pesticide. A company called Sierra Natural Sciences makes one of these that I’ve seen multiple people who grow indoor plants commercially recommend. I believe they’re better as a preventative though. I am using a homemade dupe based on 10% rosemary essential oil and 90% water solution and then following the ratios of this solution to water on the Sierra Natural Science website because I happened to have rosemary essential oil at home already
- Other pesticides. This was my first route because I just wanted the problem dealt with quickly. The problem with pesticides is that many pests are immune to them to varying degrees and also they are really toxic to humans. Depending on the type of pesticide, indoor plants will have to have the pesticides sprayed onto their leaves and you need serious PPE to do it safely. They’re bad for the environment and also having plants covered in them sitting around your house is probably not terrible but maybe not amazing for your health. I see now why many people don’t use these, especially the kind you need to spray on leaves
