Aphid Advisory

Several years ago I signed up to receive advisories put out by the Utah State University. These advisories are centered around the principle of Integrated Pest Management.

Today, I received this advisory on aphids which at first seemed very odd for this time of year, until I read it. Very interesting. It seems that this past years’ weather patterns (cool, wet spring that is now being followed by a dry, warm fall) has resulted in all kinds of “unusual” insect activity in northern Utah for 2010.

From the advisory:
“It is normal for aphids to take flight in late summer and early fall for egg-laying, but the numbers that are occurring now are far beyond “normal” populations. Starting about a month ago, they started swarming, from the mid-section of Utah to Brigham City and parts north. Winged aphids are covering people’s clothes, cars, and falling like rain. Wingless aphids are feeding on tomatoes, peppers, fruit trees, and ornamentals. A variety of species have been identified, including witch-hazel gall aphid, bird cherry-oat aphid and related species, leafcurl plum aphid, mealy plum aphid, and green peach aphid, all of which are migratory, multi-host insects with an intersecting life cycle.”

I had no idea, first off, that there were this many varieties of aphids and secondly that they could travel as far and wide as they do. Winged aphids can travel hundreds of miles with assistance from low level jet winds.

Some more interesting facts:
• Eggs that hatch in spring on the primary host (usually a woody plant) are all females.
• Once fully grown, those female adults give birth to live female nymphs that are genetically identical to themselves.
• This process continues for several generations on the primary host until overcrowding, causing adult females to give birth to female offspring that form wings.
• These winged females leave the primary host for herbaceous plants for the summer, such as weeds, a field crop, perennials, or vegetables. There, they spend the summer, continually expanding their population through live birth to wingless females.
• As the day length shortens in the fall, adult females are once again triggered to produce large numbers of winged offspring, which this time, are both male and female.
• These winged aphids then migrate back to their preferred primary host for feeding and egg-laying. The winged females give birth to sexual females nymphs, that, when mature, are able to mate with the winged males that migrated from the herbaceous hosts. These females then lay eggs for overwintering.

Their ability to survive is nothing short of amazing. But then, I am constantly in awe of how nature can devise creative methods of adaptation to ensure its survival.