I've been hearing a lot about flat mites lately among my local Hoya community as well as the broader community as a whole. It seems like this is a wide spread issue that has been going around everyone's collections. As far as I'm aware I have not personally dealt with them however I think it is important to share resources I've seen for anyone who may be dealing with them.
In the July 2022 issue of the Stemma Hoya journal there is an article on pages 21-28 that talks identification, detection, life cycle, treatment, and prevention of flat mites. Adam aka Knot Dude on YouTube also has a really great video about flat mites. Click here to watch that. I really liked the detailed pictures he showed on identification.
0 Comments
A few weeks ago I was listening to episode 2 of Let's Talk Hoya. I believe it was Adam that mentioned he used Hydroguard as well as PureCrop1 in his plant care. I have been meaning to try Hydroguard since March but never got around to purchasing it. Instead, I let it sit in my Amazon save for later list till I listened to this episode and decided to finally try it. Hydroguard is supposed to help with root rot which is perfect because I tend to overwater. I have been using it for the last few weeks in LECA as well as LECHUZA-PON. Hydroguard can be used in soil or hydroponic gardens. So far, all my roots seem to be happy and I have no complaints. Also, you only have to use 2 ml per 1 gallon of water so 1 quart of Hydroguard is going to last a long time. The main ingredient in Hydroguard is bacillus amyloliquefaciens. This bacillus grows near plant roots which stimulates growth and can suppress pathogenic bacteria and fungi. Note that this product is to be used as a preventative and not to cure an already diseased plant.
Before listening to this episode, I had not heard of PureCrop1. This product piqued my interest because I have been dealing with root mealybugs the last couple months. PureCrop1 is marketed as an insecticide as well as fungicide. PureCrop1 is 100% plant based and is considered food grade. I have only used it a few times on a large Hoya that has had root mealybugs that I didn't want to chop and prop. Granted, I haven't been following the directions properly (oops). I have only added it into the water for said plant about once a week during my normal watering schedule. The product is intended to be used as a soil/foliage drench for 3-4 days in a row. The directions also suggest to continue using it at a lower dilution every 7-12 days after that. References: Siemering, Geoffrey. (2016). The Value of Bacillus amyloliquefaciens for Crop Production. Microbial Cell Factories. https://www.researchgate.net/publication/326816582_The_Value_of_Bacillus_amyloliquefaciens_for_Crop_Production One product I've just started to experiment with is sulfur. Sulfur use in the Hoya community seems to be on the rise due to the increase in mites among collectors. It can be used to treat various pests such as mites, thrips, and scale. It also has been effective in treating powdery mildew. I purchased the Bonide sulfur dust. You can use sulfur in dust form, mix it with water to make a spray, or mix with water to create a paste to paint on. I opted for the spray as I decided to treat my whole collection. To make the spray combine 3 tbsp per 1 gallon of water. The sulfur mixture can clog up spray bottles. I used my usual glass spray bottle and didn't notice any issues. The spray will leave a residue on your foliage and it does have a slight odor. It is recommended to wear a mask while spraying. Additionally, it is stated on the label to not spray during hot temperatures and do not use sulfur within two weeks of an oil spray such as neem. My plan is to leave the sulfur on the foliage. From what I've heard you can either leave the sulfur on the leaves or wipe it off. If you choose to wipe it off I would give it two weeks and then wipe off with water or leaf shine. I also experimented with the paint on method via H. 'Silver Dollar'. The other day I noticed that three of the leaves had some type of unknown scabbing on them and I figured a treatment of sulfur couldn't hurt. I didn't measure out a ratio of water to sulfur dust while making the paste. I mixed enough water into the sulfur to get a pasty texture. I used a paint brush and went to town. If you do paint on the sulfur, I would recommend wiping it off within a week or two because most likely it will be harder for the plant to photosynthesize properly with globs of sulfur on the surface of the leaves. Sulfur is also a fertilizer and can help promote plant growth. It will decrease soil pH as well as sodium levels. I have heard good things about people seeing new growth on their Hoyas from using sulfur two weeks after application. Moreover, I read on one of the Facebook Hoya pages that you can water sulfur into the soil to help with bacterial infections. The user said to mix 1 tsp of sulfur per 16oz of water. It seems like there are a lot of benefits to using sulfur and hopefully I will be experiencing them soon. I noticed what I assumed to be powdery mildew on my Hoya Sunrise x unknown. This plant in particular I grew from seed and is just shy of being a year old. Certain vines on the plant had a white flour-like substance on them. I treated it multiple times with cooper fungicide but didn't notice any difference. I also used leaf shine to wipe off the leaves individually but it didn't seem to help. I saw someone post on one of the national Facebook groups about this issue and it was commented that it might be salt build up on the leaves. The recommendation was a 1:1 ratio of water and alcohol to wipe down the leaves. I tried this as well with no luck solving the problem. My latest attempt has been spraying on sulfur. There are still a few noticeable spots on some of the affected leaves but they don't look quite as powdery as before. Hopefully, another sulfur treatment or two will take care of the issue.
Root mealybugs are small rice sized white cotton-like insects that live in the soil of a plant. Instead of feeding on foliage sap like regular mealybugs, root mealybugs feed on root sap of the plant. It can be hard to initially spot an infestation, unless you are checking the roots. The main sign of a root mealybug infestation is an unknown decline in plant health. Declining plant health can happen for numerous reasons but it 's important to rule out root mealybugs. UK houseplants. (n.d.). Root mealybugs. Root Mealybugs. Retrieved February 20, 2022, from https://www.ukhouseplants.com/pests/root-mealybug. Root mealybugs are more dormant in the winter with the life cycle taking up to 4 months to get from egg to mature adult. In the summer, root mealybugs can mature from egg to adult in as little as a month. The white powdery areas in the above image show where the egg sacs are. Once the eggs hatch into nymph’s aka crawlers, the insects are ambulatory and spread easily. Do not use the same water between plants as nymphs can be transported via water. Due to the high mobility of these insects, it's recommended that you do not put any plants anywhere near an infested plant. Root mealybugs can be a vexing pest to deal with and can return after the infestation is gone. One method to dealing with root mealybugs is simply getting rid of the infested plants. Other methods include chopping the roots off completely and propagating, using systemic insecticides with the active ingredient imidacloprid, and soaking the roots in hot water. If you use the chop and prop method, I would recommend soaking the cuttings in alcohol spray solution for 10 minutes and using a soft-bristled old toothbrush to gently scrub down the stems/leaves. Do not reuse the same grow medium when repotting/propagating. Once potted up, add in systemic insecticide (granules or liquid). Note that using systemics is not a one-time application but will require periodic usage throughout the year. Alcohol spray: 1/2 cup isopropyl alcohol 70% 4 cups water The hot water bath method is effective if the temperature is 120F. To do this take the root ball of the plant and immerse it completely in the hot water for 10 minutes. This should be enough time to kill any living mealybugs on your plant. References: Hodgson, L. (2017, February 10). Root Mealybugs: Death From Below. Laidback Gardener. https://laidbackgardener.blog/2017/02/10/root-mealybugs-death-from-below/#:~:text=Root%20mealybugs%20are%20active%20all Bethke, J. (2013). Spring 2013: Hot Water Treatments to Control Pests. Ucnfanews.ucanr.edu; University of California, Division of Agriculture and Natural Resources. https://ucnfanews.ucanr.edu/Articles/Regional_Report_San_Diego_and_Riverside_Counties/Spring_2013__Hot_Water_Treatments_to_Control_Pests/ Mealybugs are a type of scale insect that have a wax coating. Females are wingless and have a soft oval body. Male mealybugs are smaller with wings and a tail. The average life cycle of a mealybug is 6-8 weeks. These bugs live in warm environments and feed on plant sap. Once they feed, they leave behind honeydew which is their excrement. The longer a plant is exposed to mealybugs the more likely plant growth will slow and leaves may drop. NOTE: Some Hoyas produce nectar. It can be difficult to tell honeydew/nectar apart. Inspect plant closely for pests. Mealybugs can be easily identified due to their cotton-like appearance. However, these bugs are great at getting in the nooks and crannies of a plant. Make sure to check between nodes, near stems, and under any supports (e.g. clips, velcro) you have if the plant is trellised. Always quarantine any pest ridden houseplants. If you notice a few mealybugs on your houseplant, you can spot treat with 70% isopropyl alcohol. Take a cotton swab and dip it into the alcohol. Apply the end of the swab directly on the mealybugs. If you notice a large infestation of mealybugs you will want to use a diluted alcohol solution to spray the plant.
Alcohol spray: 1/2 cup isopropyl alcohol 70% 4 cups water If you don't have isopropyl alcohol, you can also use neem oil to kill any life cycle stage of a mealybug. Neem oil comes in concentrate or premade solution. For neem oil concentrate follow the direction on the bottle. If you plan on using neem oil make sure to apply it in the evening to avoid foliage burning. *Note if you use concentrate make sure you use warm water and some type of castile or dish soap to act as an emulsifier with the neem oil. Concentrate: 2 cups warm water 3/4 tsp neem oil concentrate 2-3 drops of free & clear dish soap or castile soap Apply preferred pest control method once a week for 2 months to ensure elimination of mealybugs. Click here to read about root mealybugs. |
Archives
March 2024
Categories
All
|