Brithys crini, the amaryllis borer, crinum borer,
Range
It is found in the coastal areas of
Southern Europe and
North Africa, south to
South Africa. Furthermore, it is found in
Japan and in
Queensland and Northern Territory in
Australia towards
India and
Sri Lanka.
Description
The
wingspan of the moth is about 40 mm. Its head, thorax and forewings are very dark brown, but paler toward the wingtips. Sub-basal, median and postmedial indistinct waved lines are black. A curved submarginal ochreous line with ferrous colored lunules found on each side of it. There is a marginal black lunule series. The hindwings are practically white.
Arthropod leg bear black and white stripes. In Europe the adults are on the wing in July.
Life stages
There are several generations per year, though development slows down in cooler seasons, when the larvae sometimes overwinter by boring into the bulbs of the host plants.
The moth lays clusters of a few dozen eggs on the host plant leaves. The hatching larvae at first remain in groups and mine into the leaves. As they grow they either emerge and feed externally, or proceed down the leaves to their bases or even into the bulbs.
The are Aposematism coloured in pale yellows on blacks and browns. They are unpalatable to most vertebrate predators, and also poisonous, feeding as they do, on largely unpalatable and poisonous plants. They are slightly bristly, but the bristles seem to be sensory rather than irritant. Typically they grow to about 40 mm long before .
Food plants
The larvae feed on all species of
Crinum,
Clivia and
Hippeastrum, including
Crinum angustifolium,
Haemanthus species,
Hippeastrum procerum,
Pancratium maritimum,
,
Crocus tommasinianus,
Narcissus spp., and
Amaryllis belladonna. Commonly they bore into thick leaves or even into the bulbs; Mature larvae are likely to feed externally, especially on thin-leaved plants. Heavy infestations of the caterpillars may kill plants.
Predators
The most effective enemies of the larvae in Europe are the
Carabidae (
ground beetle)
Scarites buparius and the
Tenebrionidae (
)
Erodius siculus and
Pimelia bipunctata.
Control
Commercial
carbaryl dusts are effective in combating the caterpillar, but they cannot reach those that have bored into the plant. The insecticide also reduces populations of predators, so that weekly applications become necessary. For small scale horticulture, or in home gardens it is better to rely on mechanical control, seeking out discoloured feeding patches on leaves and crushing the young larvae before they develop. Heavily infested leaves it often is better to cut out and destroy.
External links
