This bug is creeping around your property. He may be friend or foe.

Name: Acyrthosiphon kondoi

Alias: Blue alfalfa aphid. This is a small green aphid that is teardrop shaped and flightless. It is very similar to other aphids and is most often confused for the pea aphid. There are a few ways to tell them apart. They do not have any dots or markings on their antennae, and they can have a slight blue tint to them when compared side by side with a pea aphid. Both of these discrepancies are difficult to tell without a proper microscope. They are very quick to reproduce and can do so multiple times a year.

Crimes: Like its other cousins, it pierces and sucks sugar directly from the plant. However, this little glutton can cause more damage, so the threshold in which action is required is much lower than that of pea aphids or other aphids. Most aphids require a large population before they become a problem. Blue alfalfa aphids can cause damage in fewer numbers.

Redeeming Qualities: None known.

Sentence: There is a wide array of pesticides that are effective against blue alfalfa aphid. However, I would recommend only using pesticides as a last resort to control them. Their rapid reproduction rate allows them to build resistance to pesticides. Oftentimes, pesticide applications knock back natural predators as well as the target, and with insects such as the blue alfalfa aphid that can rapidly reproduce, they can rebound without any pressure from natural predators. Frequent applications can lead to ineffective applications. If you find a need to apply frequently, you need to shift your focus to developing an environment that supports the presence of natural predators in borders and green spaces.

For more information on dangerous and beneficial bugs, call UI Extension educator Joseph Sagers at 208-270-4031 or email

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