There's gold on them thar roses.
No, not the kind of gold found during the California Gold Rush (1848–1855) that brought some 300,000 folks to the Golden State.
These are gold eggs from the multicolored Asian beetle, Harmonia axyridis, that we found on our Sparkle-and-Shine roses last week. The aphids are sparkling and the lady beetles are shining.
A native of eastern Asia, the multicolored Asian beetle was introduced in California by the U.S. Department of Agriculture in 1916, and in 1964 -1965 for the biological control of pecan aphids. Later, from 1978 through 1982, released beetles took hold in Connecticut, Delaware, Georgia, Louisiana, Maine, Maryland, Mississippi, Ohio, Pennsylvania, and Washington.
The multicolored Asian beetles are tiny, about 7 mm long and 5.5 mm wide. Spots? They range from as many as 19 spots to no spots at all. Color? From red to orange to yellow and (rarely) black. A key identifying characteristic is the black M-shaped mark behind its head.
The beetles, commonly known as ladybugs (but they're beetles, not bugs), are from the family Coccinellidae and they eat lots and lots of aphids and other soft-bodied insects, including scale insects and mites.
Aphids are not your friends. With their piercing mouthparts, they suck the juices right out of your plants, including your favorite roses. Lady beetles are your friends. They have voracious appetites and can gobble up 50 to 75 aphids a day.
Lush new growth often means a gathering of aphids, which means a gathering of lady beetles. Look closely and you might seen a cluster or row of about 20 oval eggs on the leaves.
That's the gold.
And so the cycle continues.
(Note: If you're looking for more roses, the California Center for Urban Horticulture, UC Davis, has just announced its 10th annual Rose Days will be Saturday and Sunday, May 6-7, from 10 a.m. to 4 p.m. at the Foundation Plant Services parking lot, 455 Hopkins Road, UC Davis campus.)
"Well, yes, I would like some aphids for dinner," said every lady beetle (aka ladybug) everywhere.
With the lush green growth of spring, come aphids (the prey) and lady beetles (the predators).
And now, if you look closely, you'll see clusters or rows of lady beetle eggs on your roses. Luck be a lady...
"The name 'ladybug' was coined by European farmers who prayed to the Virgin Mary when pests began eating their crops," National Geographic says on its website. "After ladybugs came and wiped out the invading insects, the farmers named them 'beetle of Our Lady.' This eventually was shortened to 'lady beetle' and 'ladybug.'"
Globally, we have some 5000 species of lady beetles. Entomologists call them ladybird beetles. Yes, they're beetles, not bugs. The term, bugs, applies to insects in the order Hemiptera, while lady beetles belong to the order Coleoptera.
Lady beetles range in color from red to orange to yellow, with or without spots. See the UC Statewide Integrated Pest Management Program website for photos and descriptions.
The red and orange are warning colors in nature. Hey, don't eat me. I don't taste good! You'll be sorry! In fact, their hemolymph is both toxic and foul-smelling. Predators steer clear of them.
Although lady beetles don't taste good to predators, aphids are a different matter. Aphids are apparently quite tasty. One hungry lady beetle can gobble up about 50 to 75 aphids a day or 5000 over a lifetime, scientists say. But who's counting? There's no "Weight Watchers" or "Waist Watchers" program in place.
Lady beetles also devour other soft-bodied insects, such as scale insects, white flies and mites.
Today (March 20) marked the first day of spring and the international Day of Happiness, one and the same. Rain pelted our roses, and doused the lady-beetles-that-were-eating-the-aphids, and the aphids-that-were-sucking-the-plant-juices and the roses that were just trying their darndest to grow.
Meanwhile, the goldlike eggs just glistened...with promises of a new generation of lady beetles...
Have you checked your rose bushes lately? Along with the lush new growth, you'll probably notice a new crop of aphids. And if you look closely, probably lady beetles (aka ladybugs).
The UC Integrated Pest Management Program (UC IPM) defines aphids as "small, soft-bodied insects with long slender mouthparts that they use to pierce stems, leaves, and other tender plant parts and suck out fluids." Basically, they're pear-shaped insects with long legs and long antennae and may be green, yellow, brown, red or black "depending on the species and the plants they feed on," according to UC IPM. "Almost every plant has one or more aphid species that occasionally feed on it. Many aphid species are difficult to distinguish from one another; however, management of most aphid species is similar."
"A few species appear waxy or woolly due to the secretion of a waxy white or gray substance over their body surface. Most species have a pair of tubelike structures called cornicles projecting backward out of the hind end of their body. The presence of cornicles distinguishes aphids from all other insects."
UC IPM also says that most aphids don't move rapidly when disturbed. That's the truth! Sometimes they're just a 16th of an inch away from a lady beetle that's gobbling up their siblings.
The lady beetles in our garden today were primarily the multicolored Asian lady beetles (Harmonia axyridis), also known as Harlequin lady beetles. They're native to China, Russia, Korea and Japan. In colder parts of the world, they're considered a nuisance when they overwinter in large congregations in walls, windows or attic. They leave unpleasant odors and stains.
Friend or foe? They're more of a friend, at least here in sunny California.
The circle of life...
Monarch caterpillars feast on milkweed, their host plant. Oleander aphids feast on the juices of milkweed plants. Lady beetles, better known as ladybugs (but they're beetles, not bugs) feast on the aphids.
The milkweed is the only plant that the monarch caterpillars eat. Oleander aphids, as their name implies, are also commonly found on oleander. And lady beetles not only eat aphids, but soft-bodied insects such as scales, white files, mites, and yes, monarch butterfly eggs.
The UC Statewide Integrated Pest Management Program (UC IPM) says California has some 200 species of lady beetles and that "most are predators both as adults and larvae."
If you've ever watched a lady beetle go through the aphid cafeteria and select the menu (big, little, small, winged, wingless, fast, slow, near, far), it's quite a sight.
One lady beetle can eat 50 aphids a day, scientists say. During its lifetime, that can mean 5000 aphids.
As for the oleander aphids (Aphis nerii), they derive their name from Nerium, the genus name for oleander. Both are the oleander and oleander aphid are reportedly native to the Mediterranean region.
If you have milkweed, you probably have aphids. Oleander aphids. And you probably have lady beetles eating those aphids. And the monarch eggs...
The circle of life..
Monarch butterflies aren't the only insects that like milkweed.
Honey bees, lady beetles and aphids, do, too.
We found all three insects, plus a monarch butterfly, on our scarlet milkweed (Asclepias curassavica) today (Labor Day). Most of the insects were oleander aphids, which attract lady beetles. aka ladybugs.
Asclepias curassavica, also known as tropical milkweed, and Mexican butterfly weed, is native to South America but is frequently planted throughout the United States to attract monarchs. In the United States, you'll find it not only in California and Florida, but in Hawaii, Louisiana, Tennessee and Texas, among others states. The colorful plant is known by some as "redhead," due to its brilliant red (and yellow) flowers.
Unfortunately, some of the "yellow" is a pest that needs to be eradicated. See the UC Statewide Integrated Pest Management Program (UC IPM) guideline on aphids.