Tuesday, July 27, 2010

Friend of the Week: Lady Beetles

Lady Beetle
(Coccinellidae Family – many different species)

Why a Friend: Known as ladybugs, ladybird beetles, and lady beetles, larvae and adults aggressively eat soft-bodied insects. There are many native populations in any given spot throughout the world. The Mexican Bean Beetle is a well-known member of the Coccinellidae Family and is not carnivorous. Both larvae and adults of this species prefer eating bean plants.

Predator of: Aphids, mealybugs, whiteflies, scale insects, thrips, psyllids, and spider mites. Lady beetles can eat 40-50 aphids per day and 200-500 within their lifetime.

Life Cycle: Adult lady beetles overwinter in field edges under rocks and leaf litter. They prefer any protected area and sometimes they choose to come inside homes. When encountered inside the home, the insects can be transferred outside into a sheltered spot for the winter. In warmer climates, the adults will slow their development relative to the temperature. Adults emerge in the spring looking for a food source and place to lay eggs. Eggs are laid in masses or singly, depending upon the species, where there is a source of food for the newly hatched larvae. The eggs hatch and larvae begin to feed right away. Lady beetle larvae look like small alligators with six distinct legs. These larvae can differ in color and size, depending upon species. Some are black and/or gray with red or yellow spots. They go through three instar stages before forming a pupa. The adult emerges from the pupa to find a mate and feed on prey.

Lady Beetle Larvae

How to Identify: The lady beetles have three body segments: the head, the pronotum, and the abdomen. The elytra (wing covers) cover the abdomen and can vary in color from yellow, brown, red, to black. Spots are present on some species and not on others and can be variable within a species. Ohio State University has published a Fact Sheet on Lady Beetles as well as an Identification Guide with images and features of common species. Keep in mind that native populations may vary in certain areas, so it is best to check with local cooperative extension agencies when it is critical to positively identify certain species. Lady beetles will exude a pungent-smelling odor when disturbed.

How to Attract: Lady beetles eat mostly soft-bodied insects but occasionally supplement their diet with pollen and nectar. Planting an insectary garden will help bring in native lady beetles by attracting aphids that will not be pests on vegetable crops. These plants will also provide pollen and nectar as an alternate food source for lady beetles. These insectaries will attract other pest predators, as well. We recommend planting the following and letting them go to flower in your insectary planting: Beneficial Insect Attractant Mix (#1832), Colorado Yarrow (#1338), Genovese Basil (#911G), Blue Spice Basil (#181), Mrs. Burns’ Lemon Basil (#774), Common Chamomile (#914), Santo Cilantro (#2928), Bouquet Dill (#920G), Grosfruchtiger Leaf Fennel (#2395), Forest Green Parsley (#529), White Dill Ammi (#1034), Jewel Mix Nasturtium (#1420), and Mammoth Red Clover (#980G). Discouraging ants from ‘farming’ aphids will aid in the lady beetles’ access to their prey.


Further Resources


View all Johnny's seed varieties that Attract Beneficial Insects »

To learn more, visit our Grower's Library for articles on Attracting & Putting Beneficial Insects to Work »


References:

http://www.ext.colostate.edu/pubs/insect/05594.html
http://www.nysaes.cornell.edu/ent/biocontrol/predators/ladybintro.html
http://edis.ifas.ufl.edu/in327
http://ladybeetles.osu.edu/images/Lady_beetle_guide_5-6.pdf

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