Asian Beetle - Falls Creek Animal & Pest Control

Asian Beetle

This species was possibly established in North America as the result of introductions into the United

States in an attempt to control the spread of aphids. Whatever the source, in the last two decades, this

insect has spread throughout the United States and Canada and has been a prominent factor in

controlling aphid populations. However, many people now view this species as a nuisance, partly due

to their tendency to overwinter indoors and the unpleasant odor and stain left by their bodily fluid when

frightened or squashed. (It is also currently increasing in Europe to the detriment of indigenous species,

due to its voracious appetite which enables them to out-compete and even eat other lady beetles, as it

also does in the United States.)

In the U.S., the first attempts to introduce it took place as far back as 1916. Repeated efforts were not successful. In the early 1980s, aphids were causing significant problems for growers of pecan trees, so the United States Department of Agriculture again attempted to bring the insect into the country—this time in the southeastern United States, using beetles brought from their native region in northeastern Asia. After a period of time, USDA scientists concluded that their attempts had been unsuccessful. However, a population of beetles was observed near New Orleans, Louisiana around 1988, though this may have been an accidental introduction event independent of the original, planned efforts. In the following years it quickly spread to other states, being occasionally observed in the Midwest within 5–7 years, and becoming common in the region by about 2000. The species was also established in the northwest by 1991, and the northeast by 1994, in the former case quite possibly involving additional introductions, rather than reaching there from the southeast. It is reported that it has heavily fed on soybean aphids (which recently appeared in the U.S. after coming from China), supposedly saving farmers vast sums of money in 2001. However, in addition to its household pest status, it has been reported to be a minor agricultural pest (contaminating crops of tender fruits and grapes). in Iowa, Ohio, New York State, and Ontario. The contamination of grapes by this beetle has been found to alter the taste of wine. Native ladybird species have experienced often dramatic declines in abundance in areas invaded by H. axyridis. Despite the troubles the Asian lady beetle causes, many farmers still view it as a beneficial insect.

These beetles can sometimes be difficult to identify because of the variations in color, spot size, and spot count of the elytra. The easiest way to identify an Asian lady beetle is to look at the pronotum and see if the black markings look like a letter “W” or “M” (depending on if the marking is viewed from the front or the back). There is more white on the pronotum in this species than in most native North American species.