Six-legged Plagues Afflict Farm and Forest
Six-legged Plagues Afflict Farm and Forest
The color purple is not so common in nature, and so it immediately grabs our attention when we round a bend on a southwest Virginia backroad to discover a striking triangular box of Easter-egg purple hanging inexplicably from a tree.
Walk back and look closely at any of the three sides of these purple boxes. You will see small bits of storm-blown treetop debris and hapless collateral-damage insects stuck to the glue of its surfaces. But thankfully, to date in part of the commonwealth, none of the trap’s intended victims–the long, slender emerald-green ash borer beetle–(EAB) will have been lured by either the color or the impregnated, irresistible scent.
But the bad news is that these Asian invaders have moved into northern Virginia–and into twelve other states since their destructive presence was first observed in Michigan in 2002. Why we should care is the fact that 16 native ash species contribute some 8 billion trees to our forests. The wood is hard and durable. It is used in baseball bats and furniture, as well as other uses. Ash wood products are worth some $25 billion a year, and currently, a comparatively small $30 million is being spent each year to protect the species. The current purple trap census is a part of that effort.
EAB is likely spread in nursery transplants of ash trees or by movement of lumber or firewood. For those of us who burn wood for heat, we should buy it locally rather than from a distance, to reduce the chances of helping spread this forest killer.
Meanwhile, since it is neither possible or prudent to spray insecticides over entire forests, entomology and forestry departments are looking for a suitable small “parasitoid” wasp species (smaller than the head of a pin) as a biological control that will seek out and lay its eggs in EAB larvae before an adult beetle can emerge. Failing that, the beetle larvae eat away the cambium, which eventually kills the tree. The mature insect then exits through a characteristic D-shaped hole.
The survey is being handled by a federal contractor hired by APHIS (Animal and Plant Health Inspection Service.) To report a damaged or fallen trap, call 877-207-9406.
(HINT: If you wouldn’t know an ash from a whole in the ground, the traps are hung only from ash trees, so take a close look and learn to recognize the ash trees in your forest.)
Now, much closer to (and very likely inside your) home, let’s discuss a pestiferous insect of a different shape, color–and smell: the Brown Marmorated (mottled) Stink Bug (BMSB.) This one is truly a plague that has been described as being “of Biblical proportions.”
Another invader from–you guessed it–Asia, this true bug’s damage is not nearly so species-specific as the EAB. The shield-shaped stinker was first observed in the US in 1998, and since, has become a pest on more than 100 garden and orchard crops, already causing up to 100% loss of some fruit crops in the 33 states to which it has spread. Already, it outnumbers native stinkbugs 10 to 1, and its populations are still growing at an alarming rate.
With no natural predators on its adopted continent, other means of extermination are being sought. Smashing is not one of them, and insecticides just make them vindictive. Flicking them one by one from your tomatoes into a dish of soapy water is slow, but effective and satisfying. But let’s be up front here: we’re talking about approaching hordes of these things, like the surging army of Orcs and Goblins in Lord of the Rings! Who can save us?
Enter again, a tiny Asian wasp, a possible solution called Trissolcus, which, in its native Japan, Korea and China, is an effective predator of the BMSB. Much work is being done to see if this wasp might selectively search out the brown stinker and leave our native stinkers alone. You may recall that the now-familiar and delightful house guest called the Multicolored Asian Lady Bug was also brought intentionally not long ago to our shores–as a solution.
Prepare to see vastly increased numbers of brown stink bugs this year. Especially this fall, it may become necessary to shutter your doors and windows against them. Tape all cracks and crevices, use cotton balls to block your ears, and keep your mouth closed at all times. Be patient. Maybe they will eventually tire of tormenting us, and go back to the Mothership.
And finally, not to be alarmist here, but please report immediately any outbreaks of boils on your personal body or a sudden increase in the number of frogs or locusts in your locale. FEMA has response teams standing by.