The Peachtree borer moth is a member of a colorful genus https://bugguide.net/node/view/177626/bgpage, https://bugguide.net/node/view/1542696/bgpage, https://bugguide.net/node/view/2123056/bgpage,

in a colorful tribe (Synanthedonini) https://bugguide.net/node/view/1010753/bgimage,

in a colorful family https://bugguide.net/node/view/2008912/bgimage https://bugguide.net/node/view/484442/bgpage https://bugguide.net/node/view/1091609/bgimage https://bugguide.net/node/view/1113737/bgimage, https://bugguide.net/node/view/866266/bgimage https://bugguide.net/node/view/2346050/bgimage of waspy-looking, day-flying moths (some species fly for only a few specific hours of each day).  They have long, waspy legs and they can hover like wasps, too.  It’s called Batesian mimicry – a harmless species is protected by its resemblance to a harmful one – in the case of the Sesiids, adopting the aposematic (warning color) signals of a wasp.   

Some adult Sesiids feed on nectar, and the larvae of most species bore into vines or into the branches, trunks, bark, or roots of woody plants.  Some species are big pests of orchard crops and landscaping shrubs and trees.

Females send out chemical signals (pheromones) to attract males.  They “call” daily, and these calls may be sensed by males a half-mile away.  They lay eggs on various parts of their host plants; the newly-hatched larvae dig in and feed, and many eventually pupate within their plant, but not before excavating an exit and concealing it with silk.  Some species are larvae for two seasons or even longer, but adults live only for a few weeks – some for much less.  Adult Peachtree borer moths live less than a week and do not eat. 

PEACHTREE/GREATER PEACHTREE BORER MOTHS (Synanthedon exitisoa) can be found in much of North America excepting parts of the Great Plains and desert Southwest and a few Eastern states (there’s also a Lesser Peachtree borer moth that’s mostly Eastern).   

Their host plants are peach trees and other members of the genus Prunus, all sun-loving members of the rose family, and they’re considered the most destructive of the clear-winged borers – persona non grata wherever they’re found.  In the wild, they use wild cherry, wild plum, and shadbush (Amelanchier sp.). 

As one website said, “I can’t believe they’re not wasps!”  They are sexually dimorphic (two forms), and although the female may be more colorful https://bugguide.net/node/view/981311/bgimage, the male is no slouch https://bugguide.net/node/view/815698/bgimage.  Their wingspans are 1 ¼”-ish (females are larger than males), and females are probably mimics of a spider wasp https://bugguide.net/node/view/434689/bgimage.  Although they’re not aggressive, spider wasp stings can pack quite a wallop, but the moths, of course, don’t sting.  

The natural history of Peachtree borers is pretty-well documented.  Adults emerge from their pupal cases between 8:00 AM and 1:00 PM and mating commences immediately – females lay more than half of their eggs on their first day as an adult.  Eggs are deposited in cracks and crevices in the bark near the base of the tree or on the ground nearby, and her fertility is her Super Power – of the 400 to 900 (or more) eggs she lays, 97% to 100% will hatch! 

The larvae tunnel in and feed on the cambium (growth layer) of the roots and trunk just below ground level (a zone called the “root crown”), and the tunnels they leave behind intersect the plumbing of the tree, disrupting the flow of nutrients up and down the trunk and causing twigs and branches to die.  They leave piles of frass (bug poop) at the entrances of their tunnel, and they may cause a thick, gooey sap to ooze from their holes in the trunk.  While the tree damage is mechanical, the larval tunneling may introduce fungi and bacteria.

The larvae overwinter within the tree and resume eating in spring, doing more damage because they’re larger.  They pupate within inches of the base of the host tree in a silk cocoon that’s covered with frass and masticated bits of wood https://bugguide.net/node/view/165509.  After the adults emerge, empty pupal skins can be found at the base of the tree https://bugguide.net/node/view/165511. 

A PEACH OF A RABBIT HOLE

So – before peaches, Peachtree borers, a native species, hummed along in harmony with their universe, eating wild Prunus species.  When, exactly, did they encounter their first peach? 

According to the lore of some Puebloan tribes, there have always been peaches in the Southwest – the Anasazi, who walked away in the early 1300’s AD, were said to enjoy them. 

Others say that they originated in China 2.6 million years ago and have been under cultivation there for 6,000 to 8,000 years.  Peaches were grown in Persia (Iran) 2000 years ago (which explains the scientific name, Prunus persica), were spread west into Europe by Alexander the Great, and were brought by French/Spanish explorers/conquistadores to Mexico/Florida in the first half of the 1500’s (but there’s always a chance that they came over with Columbus, too).  It’s likely that the peach wasn’t embraced by the Indians until a decade or so after its introduction, when the missionaries that followed the explorers arrived to set up shop.  Once adopted, though, it spread like wildfire along native trading routes and became an important food.  Indians who were forced to travel the Trail of Tears from the Southeast to Oklahoma (1830 to 1850) carried peach pits with them.  Fifty years earlier, Washington had ordered his troops to destroy massive, mixed fruit orchards in Upstate New York in order to crush the Indians there.

Not only did they embrace it and incorporate it into their agricultural and land management systems, those consummate Indigenous plant geneticists developed many varieties that were quite different from European peaches.  In the right soil and with lots of sunlight, peaches grow easily and can plant themselves, but it takes human intervention – pruning – to develop good fruit.  Peaches grew so readily that several sources called them, along with the hogs that were also introduced by the Spanish, the first American weeds.

The bottom line – the Europeans who arrived to settle the Atlantic Coast in the 1600’s reported peaches among the bounty that the New World offered and assumed that the peaches were native.  “Here are also Peaches, and very good, and in great quantities, not an Indian Plantation without them … one may have them by Bushels for little; they make a pleasant Drink and I think not inferior to any Peach you have in England…….” said William Penn in 1683.  A few years later, early Naturalist John Banister wrote “…for the Indians have, and ever had greater variety and finer sorts of them than we… I have seen those they call the yellow plum-peach that have been 12 or 13 inches in girth.”   

A team of researchers located what they believe to be the earliest North American peaches at an archaeological dig between Atlanta and Augusta, Georgia, when they dated to 1520 to 1550 AD some peach pits that were found at the bottom of post holes (blowing out of the water the notion that peaches were introduced by the Spanish to St. Augustine, Florida in 1565 or to Mexico in 1562).  

Peachtree borers responded to the massive increase of host plants with a population boom of their own and were recognized as pests by the early 1800’s.

Yeah, yeah – the BugLady is a history geek, too.

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/