BAG WORMS	LACEBUGS	EUONYMUS SCALE

    In the spring we courageously charge into our gardens inspired by optimism and tempered by the magic of spring.  As summer arrives, we are often faced with some cultural problems.  I pride myself on being able to spot bagworms, lacebugs, and euonymus scale from 20 feet, as folks drag their plagued branches into the store for pest identification.  Man, do we look smart!  I recall years ago having a plastic measuring cup behind our seed counter which would hold exactly one pound of Contender green bean seed.  This was the most popular increment of our most popular bean.  I would weigh the seed on a balance scale with a scoop always yielding a perfect balance, and the customers would exclaim, "Man, are you good!"  I would usually just smile and nod.  Unfortunately wear and tear eventually took its toll on our plastic measuring cup.  The point is that if you say, "Arborvitae" then I say "Bagworm".  The same holds true for relationships between azaleas and lacebugs, and between euonymus and euonymus scale.

    All of these plants should be monitored closely from mid May through mid August to prevent serious damage from a heavy infestation.  If not watched carefully, you will take notice after the insects have developed a severe infestation.  Occasionally this can be lethal to the plant.  If not lethal, you have still allowed the population of your pest to proliferate.

    Bagworms are serious pests for arborvitaes, junipers, and other conifers.  You have all probably seen the little cocoon dangling on a spruce from fall through spring.  This time frame presents an excellent opportunity to control this pest by physically picking these bags off of the plant and sending them to the landfill.  Sometime in June, the worm emerges and feasts on plant foliage for food as well as material to build a new bag for the next generation.  Sometimes these guys can get so carried away that they will attach a bag to aluminum siding on a house. Any port in a storm!  When the bagworms first emerge, almost any insecticide will kill them.  After the larva has begun to mature, they develop a resistance to almost all pesticides.  One of the most effective combinations on the pest is Pyrethrin/Rotenone, a blend of naturally derived pesticides, or "natural poison" if you will.  If you don't monitor your plants, you will not notice the infestation until the trees are so thick with webbing and debris that the plant will shake like a tinseled Christmas tree would in the wind.

    Lacebugs affect azaleas, rhododendrons, and pieris when planted in the sun.  The more shade, the less lacebugs.  I always said this was because the plant had more stress in the sun.  A customer pointed out that the plant also produces more sugar in the sunshine providing a great source of food for the lacebug.  The lacebug is a small, clear winged insect that sucks the chlorophyll from the foliage leaving you with a bleached or bronzed effect.  This chlorophyll will never return, but fear not for new growth will replace the old foliage in the next season.  Knowing this, the lacebug covers the backs of the afflicted leaves with eggs for the following season.  The egg hatches about the time the new spring growth flushes out.  Having no real desire to suck on an old, tough leaf, the lacebug attacks the new and tender growth, thus continuing its life cycle. Systemic insecticides are very effective in combating the lacebug, but systemics certainly don't suit organic gardeners.  Oil sprays are a natural preventative and coats  the egg so the insect fails to hatch.  Pyrethrin/Rotenone is effective but short lived, so it must be applied when the insect is actively feeding.

    Euonymus scale is so bad that we rarely carry the plant in stock, and warn customers when they buy the plant.  Several years ago, a professor from Virginia Tech released a type of lady bug in Fredericksburg that would prey specifically upon Euonymus scale and spread to an 8 mile radius.  I once met this man and he said, "Please don't spray pesticides in Fredericksburg, you are killing my lady bugs!"  I don't know how the project is going, but we still have plenty of Euonymus scale.  Like all other types of scale, the Euonymus scale is well protected under a hard shell and is most vulnerable when he goes into "crawler" stage, leaving the shell to feed and make new little scales.  Timing is important!  According to Virginia Tech's Pest Management Guide, Euonymus scale are in the crawler stage from May 5th to June 10th (1st generation) and from August 1st through August 25th (2nd generation).  Accordingly, you should use similar insect controls to those of bagworms and lacebugs on May 10th, May 20th, August 5th, and August 15th, if necessary.  I have advised folks with severe infestations to cut the plant to the ground and haul the bugs away.  The plant usually comes back from the roots with a vengeance plus you have nothing to lose due to heavy infestation.

    There are a variety of positions on the use of pesticides ranging from "If it moves, nuke it!" to "Zero tolerance".  I personally use very little pesticides and treat only the targeted pest if my tolerance level for the pest is surpassed.  None of this is really much of an issue if you plant the right plant in the right place.  Do your homework prior to planting.  Photos by:  The Ortho Problem Solver

    See you next week.