A common
pest of the garden is the green garden looper (Chyssodeixis
eriosoma). It feeds on a variety of plants including vegetables
crops such as basil, cabbage, Chinese pea, corn, eggplant, green beans, lettuce
and sweet potato. This pest also infests ornamentals like orchids, ti and
other tropical foliage. As the name implies, the looper's movement is distinguished by
the typical "looping" fashion.
The looper’s chewing damage can leave a typical window-like appearance. This is accomplished by the young
caterpillars that consume only one side of the leaf. As the caterpillars mature,
they chew holes through the leaves and on the margins. Some caterpillars will also feed on flowers
and fruits. The larvae are green; the older
ones have faint white stripes running the length of their bodies.
The adult moth, with a 1 1/2 inch wingspan, is usually seen flying at dusk. During the day they rest
inside flowers, on vegetation, or on walls. The adult feeds on flower nectar
and honeydew.
Several parasites are present in Hawaii, as well as other parts of the
world and contribute to controlling the populations of the green garden looper.
For immediate control, gardeners can spray with Bt (Bacillus
thuringiensis). It is a bacterial
powder (sold as Dipel, Gnatrol, Thuricide
and others) which is an effective organic pesticide specific to
caterpillars, fungus gnat and mosquito larvae; it is not harmful to humans.
Bt produces a toxin
that causes the affected caterpillar to stop feeding within hours of ingestion.
In addition, Bt rapidly degrades in sunlight. For best results, applications
should be made in the late afternoon. Most caterpillars feed after dusk
anyway.
Entrust (Spinosad) is
another product which can be used against the garden looper and has a low
toxicity.
