Sunday, July 7, 2019

Not Mealy Mouthed about Mealy Bugs


I had an article come across my email a couple of days ago that, unfortunately, seems to becoming a more common occurrence.

A new plant pest has been found in Florida attacking Citrus trees and fruit. It is the Lebbeck Mealybug (Nipaecoccus viridis) a.k.a. the Spherical Mealybug. The original article can be found HERE

Lebbeck Mealybug (Nipaecoccus viridis) a.k.a. the Spherical Mealybug
Image courtesy of http://www.idtools.org/id/scales/factsheet.php?name=6983

The article goes on to say that the Lebbeck mealybug is approximately 4 millimeters (mm) long by 3 mm wide with body color black, purple to blue-green and covered by thick white, creamy, or pale yellow wax. Females produce an ovisac with a wax that is sticky when touched. In high densities, waxy secretions may appear as a continuous layer of wax, which will obscure individual mealybugs. Wax may turn yellow in older infestations. Specimens do turn black in 70% alcohol. This might be a good, quick field diagnostic, but species confirmation will require slide mounting.

I put those last few words in bold to bring me to the point of today's article. Yes, the last thing the Florida Citrus industry needed was another insect. My question is, how good do you have to be to tell the difference between one mealy bug and another?

If I had seen the above picture or the one in the article, I would have just assumed it was one of the ordinary mealies. I know I am not an Entomologist, and I knew there were a few different species, but just how many of them are there!?

So, I dug a little deeper.
While I could not find a total number of species in the world, there are over 170 species of mealybugs that occur in California alone!
And I also found this.


While adult females are wingless, which are the oval blobs in the above picture, the adult male mealybugs, which are rarely seen, are tiny two-winged insects with two long tail filaments. Personally, I had never even SEEN a male mealybug before this picture.

Many mealybug species can reproduce asexually without mating. The big fancy word for this is through a process called parthenogenesis. In this type of asexual reproduction, the female can generate an embryo without the help of a male's sperm. (Insert your own joke here)

Depending on the species and the environment, mealybugs may have anywhere from two to six generations a year. Where climates are warm or plants are growing indoors, such as a greenhouse, all stages may be present throughout the year.

Many types of perennial plants are affected by mealybugs. Among the fruit trees, citrus has the most problems, but mealybugs may sometimes be found on stone fruits such as peaches. I can tell you, I know full well that they like citrus fruit.

  I found this in the navel of my Cara Cara Orange once. 
Citrus mealybug -Planococcus citri

Mealies are piercing/sucking insects that suck the juices from a plant, reducing the plant's vigor. 

Many natural enemies feed on and kill mealybugs on fruit trees and woody ornamental plants in the landscape. These beneficial insects generally can be relied upon to keep numbers at tolerable levels. Natural enemies include a number of species of parasitic wasps that lay their eggs in or on developing mealybugs. Other naturally occurring predators of mealybugs include lady beetles (Lady Bugs), green and brown lacewings, spiders, minute pirate bugs, and larvae of predaceous midges.

If the natural predators are not controlling them well enough, then Insecticidal Soap is a good alternative. If you are not familiar with that product, Insecticidal soap is based on potassium fatty acids and is used to control many soft-bodied plant pests. Because insecticidal soap works on only direct contact with the pests, you must spray them directly for it to work. It literally dries them out to death. You can also use horticultural oil, or neem oil insecticides applied directly on them.

 The mealybugs’ waxy coating may repel most contact insecticides, and their habit of aggregating in hidden locations makes them hard to reach, so using a combination of predators and insecticides is a good idea. No, the soap does not harm most of the good bugs, just try not to spray them if you can.

A word of caution here, there are MANY, MANY homemade recipes on the Internet to make your own Insecticidal Soap. Most of them use some kind of dish soap. Read your labels carefully, if there is any kind of grease cutter in the soap, it could do more harm to the plant than the pest would have.

Mealybugs have a symbiotic relationship with ants because the ants protect them from predators and parasites. They also herd them around to different parts of the plant to "spread the wealth" as it were. 

You can find these pests on a wide range of plants, the most serious ones are that which feed on citrus; as mentioned earlier, other species damage sugarcane, grapes, pineapple, coffee trees, cassava, ferns, cacti, gardenias, papaya, mulberry, sunflower, and orchids as well as many other plants.

The good news is, you can limit their introduction into your home and garden. Mealybugs are often introduced into landscapes (and especially into indoor areas) on new plants or on tools or pots. Because adult females can’t fly and can’t crawl very fast, they don’t rapidly disperse in the garden on their own. Inspect any new plants thoroughly for mealybugs before bringing them home.

Hopefully, this has opened your eyes more to the world of mealybugs and for the fact that quarantines are in place for a reason. That Lebbeck Mealybug did not buy a ticket on its own and move to Florida, it was on something that either should NOT have been introduced into the area, or somebody didn't inspect a plant very well.

Either way, let's hope that this is an isolated incident and more will not be found.

If you have any questions about this or any of my other writings, please feel free to comment below or send me an email to TheCitrusGuy@netzero.com

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Happy Growing!
Darren

2 comments:

  1. I can definitely attest to the dish soap one. I had a small bell pepper plant that was completely infested with some sort of aphid. I got a recipe off the internet and dutifully sprayed everywhere, getting every bug. Fortunately it was only one plant because I missed the part about rinse completely after 15 minutes.

    Appreciate the post as always, Darren.

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    Replies
    1. Thanks for the affirmation of the soap recipes.
      I have read some really BAD ones that I am not sure I would spray on my kitchen counter! LOL
      Thanks too for the kind words!

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