Pest Control: Mealybugs

As with most plants, orchids can be affected by a number of pests and diseases. Not long ago, I posted about slugs. Today will be about mealybugs. I’m not an expert on orchid pests, but I would like to share my experience of them. This post will help you identify mealybugs and how to get rid of them.

Last year I found these critters living on several of my orchids. The first sign that they were around were strange cotton-like formations on the leaves. I brushed them off thinking that was exactly what it was – cotton wool. A few days later, more appeared and I noticed something poking out of one of my Phalaenopsis flowers. It was the antenna of a mealybug!

The problem by this stage was greater than I first thought. These critters had spread from one orchid to another and soon enough had reached half of my collection without me knowing.

Mealybugs are ‘sap suckers’. This means that they feed by puncturing the tissue of a plant and eating to their hearts’ content. The puncture mark can then be susceptible to infections which can weaken the plant. Mealybugs are easily identified by their colour which is a whitish-grey. Unfortunately I didn’t have the presence of mind to take photographs at the time, but you can easily Google mealybugs and get plenty of pictures. They may look cute and fluffy, but do not be fooled!

Mealybugs also produce huge numbers of offspring; several hundred eggs can be laid at any one time if the conditions are right. Males have wings, females don’t, and it is usually the females that you will find living on your orchids. They vary in size but the largest one I found was about 1cm long!

So what should you do if you spot these bugs on your orchids?

Step 1: Isolate your orchid. Mealybugs can crawl from one plant to another, especially if several of your orchids are in contact with each other. You ideally want to avoid creating ‘bug highways’ as this just makes it easier for the critters to move around. If more than one orchid has mealybugs then move all those affected to a separate area.

Step 2: Check the orchid. And I mean be thorough! You will need to check every nook and cranny of the flowers, the flower spike, leaves (top and bottom), the top inch of the orchid media and the pot. These guys love hiding in the creases of the leaves, especially on orchids with pseudo-bulbs. Check everything and remove the bugs as you find them.

Step 3: Removal of mealybugs. You can manually remove mealybugs by using tweezers or ear buds (Q-tips), which works well if there are only a few of them. Use water or rubbing alcohol with an ear bud to help remove the bugs too. The alcohol affects the bugs’ protective layer which makes them easier to destroy. It is an unpleasant process, but the bugs must be crushed if you are manually removing them.

For larger infestations, there are several videos / webpages on the internet about using insecticides. The affected orchids in my collection were treated with an insecticide which I purchased online. You can make your own at home; there are some suggestions on the internet, but these two links were helpful – Brad’s Greenhouse and Miss Orchid Girl. If you are using shop bought insecticide, make sure you read and follow the instructions carefully.

You may notice that your orchid creates a sticky sap where the mealybugs have been feasting. Wipe this away with a cotton pad and water to reduce the risk of infection.

Step 4: Repeating treatment. Your orchids will need to remain in isolation for at least 4 weeks before they can be put back to their normal place. It can take two weeks for the eggs of a mealybug to hatch. In order to ensure that you have removed them all, you’ll need to be patient.

Step 5: Repot your orchids. When you are happy that all mealybugs have been removed and they have not made a return, then it is a good idea to repot your orchid and provide it with fresh media. You can then place your orchid back where it normally lives.

If you spot this pest early enough then your orchid should make a swift recovery. The orchid that was most affected by mealybugs in my collection has created two flower spikes and is strong and healthy.

I hope this helps. If you have any questions, feel free to leave me a comment.

Happy growing.

Clare

 

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