Something has completely stripped the foliage from my anemones
(Anemone x hybrida). All that is left is flower stalks and flower
buds. I live with a sizable deer population and do not think they
are to blame – this damage is different. I managed to catch one of
the insects I think is responsible. Can you identify it and tell me
how to control it in the future?
A. The insect enclosed with this question was a
blister beetle (Epicauta pennsylvanica). Blister beetles often
feed in groups (gregariously) and are quite capable of stripping
foliage from many species of plants, including ornamentals and
vegetables. They seem to arrive like a biblical plague, then
disappear. They are considered important pests of alfalfa,
especially in western states where their populations are greater due
to drier conditions and higher grasshopper populations.
feeding does not result in economic damage to the crop, dead beetles
crushed into bales of hay present a toxicity hazard to livestock
eating that hay.
Horses, cattle, sheep and poultry can be
poisoned if they consume too many dead blister beetles in baled hay.
Horses are especially sensitive.
Other species of
blister beetle can also be found in Pennsylvania, including striped
(E. vittata), ashgray ) Epicauta fabricii) and margined (E.
pestifera). They are called blister beetles because they contain
cantharidin, a defense chemical that protects them from predators.
If you accidentally crush one, it can cause painful blisters on your
skin. That is the same substance that is so toxic to livestock.
Adults have long –
three-quarter to one inch – narrow bodies. The sharp division
between head and thorax makes blister beetles appear to have necks,
unlike most insects. The head and thorax are ant-like, and they have
long antennae that are about one-third the length of their bodies.
They feed on pollen and nectar as well as foliage and are very
attracted to flowers. Your anemone flowers must have survived
because they were not open yet.
LIFE CYCLE OF BEETLES
Adult females lay
cluster of eggs in the soil in late summer, especially near
grasshopper eggs pods. Once the blister beetle eggs hatch, the small
larvae search actively for grasshopper egg pods. Once a larva finds
one, they feed and molt at short intervals, eventually losing the
legs that made them so mobile at first. They pupate in the soil and
hatch as adults in mid-late summer, depending on the species and
beetles are not the problem for home gardeners that they are for
farmers and horse owners, such localized outbreaks can occur
occasionally. Chance are, most gardeners will not even notice them
until the damage is severe, and then it is too late to do anything
about it. The blister beetles will have moved on, and you may never
see the culprit that damaged your plants. Preventative sprays are
not recommended, even in alfalfa fields. If you find them, put on
gloves and carefully knock them into a jar of soapy water. Do not
handle them with your bare hands, even after they are dead, to avoid