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May 11 @ 07:54

 

 

 

 

 

 

 

 

 

 

 

 

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Gilles San Martin from Namur, Belgium - Coccinella magnifica

Ladybug- The Real Deal

Yesterday evening Charlie and I released 1,500 live Ladybugs in the Garland Community Garden. We got this bag of insects for free at the continuation of  Earth Day in the City of Garland. 

According to legend, during the Middle Ages crops were plagued by pests, so the farmers began praying to the Blessed Lady, the Virgin Mary. Soon, ladybugs appeared in their fields, and the crops were miraculously saved from the pests. They associated their good fortune with the black and red beetles, and so began calling them lady beetles.  In Germany the Ladybug is called Marienkafer.

Just for the record, ladybugs are beetles, not bugs.  Gardeners like this insect because they are experts at keeping aphid populations in the garden under control.

But,when it comes to ladybugs, it’s important to know there are some ladybugs lookalikes that smart gardeners do not count as their “best buds” or “beneficial insects.”

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Nasty Ladybug Imposters

I know of two ladybug lookalikes.  There may be more.  Unlike the ladybug, these pests are bugs.  Confusingly so, both have the same common name of harlequin bug.  The best ways I know to tell the differences are 1) these insects are generally a little larger than the ladybug and their shape is less round and more oval.  2) The plants where I find them are almost always members of the Brassicaceae family. This family contains the cruciferous vegetables, including species such as Brassica oleracea   (e.g., broccoli, cabbage, cauliflower, kale, collards), Brassica rapa  (turnip, Chinese cabbage, etc.) Napus (rapeseed, etc.),Raphanus sativus    (common radish), Armoraciarusticana  (horseradish)

Note on another Pest of the Brassicaceae family—the white butterfly:

Pieris rapae and other butterflies of the family Pieridae are some of the best-known pests of Brassicaceae species planted as commercial crops. The white butterflies use plants from the Brassicaceae family (particularly cabbage) as host plants.  The caterpillar of the white butterfly is also known as “the cabbage worm.”

If your plants with edible greens aren’t looking healthy, most likely it’s the fault of the harlequin bug or the caterpillar of the white butterfly.  My method of control is to pick the bugs off and dump them in a bucket of soapy water. 

To organically control harlequin bugs, some folks plant fast-growing mustard early in the spring as a sacrifice plant.  They remove the infested plant to the trash (not to the compost) and then plant their other leafy greens.

  

Mating Pair Murgantia histroinica - WIKI Commons: Judy Gallagher - http://www.flickr.com/photos/52450054@N04/9340575446/

Common name: Harlequin Bug

scientific name: Murgantia histrionica   

It feeds on its host plant by sucking the plant’s juices.  It literally sucks the plant to death.  This insect prefers cabbage and cabbage-related plants such as kale, broccoli, and cauliflower.  If not controlled, this pest has the ability to destroy an entire crop. You can forget any kind theories about “living in harmony” with the harlequin bug.  Either you will eat your leafy greens, or it will. It was introduced in the USA from Mexico at the time of the Civil War.  If the leaves on your kale or cabbage look like they are skeletons with just the vein structure left.  Look for harlequins on your plants.  Most likely you will find lots of them.

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Harmonia axyridis – Wiki Commons- Harmonia axyridis source: http://home.tiscali.be/entomart.ins

Common Name:  Harlequin Bug
Scientific name:  Harmonia axyridis

This species became established in North America as the result of introduction into the United States in an attempt to control the spread of aphids. In the last three decades, this insect has spread throughout the United States and Canada, and has been a prominent factor in controlling aphid populations. In the US, the first introductions took place as far back as 1916.  This bug is also know as the “Halloween Beetle” as it comes into homes around the end of October to prepare for overwintering.

The Harmonia axyridis looks more like the lady bug than the Murgantia histrionica.  The only way I can tell the difference is to 1) observe the health of the plant and 2) the size of the insect.  If it is somewhat larger than the average ladybug and the condition of the plant is not that great, it is likely the insect is Harmonia axridis and not a ladybug.

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