Sunday, September 23, 2012

Beware of the Higad! (Tussock Moth Caterpillar)

Beware of the Higad! (Tussock Moth Caterpillar)
Dr Abe V Rotor

We call it samrid in Ilocano, higad in Tagalog and Pilipino. It is perhaps the most avoided insect next to the putakti or paper wasp. Unlike the latter, the injury one gets by contact with this spiny caterpillars is far reaching - it can spread to other parts of the body. Thus the rule is: Never rub - not even touch, the affected area. If feasible, light a candle, train the drops on the embedded spines, allow to solidify, then lift off. In this way the spines are pulled out without much damage. Apply vinegar to neutralize the alkaline chemical substance. Taking a bath without vinegar treatment will only spread the minute Neptune spear. There are people who are extremely allergic to higad that they need immediate medical treatment with antihistamine drug.

Rusty Tussock Moth (Orgyia antiqua). This specimen of Tussock Moth caterpillar belongs to Family Lymantiidae, Order Lepidoptera.  It is a commonly found on Fire Tree (Delonix regia) which blooms in summer. The colorful caterpillar, about an inch long in its last instar, dangles from the tree with spinneret and sways in the slightest breeze. It often lands on a passerby and causes extreme discomfort that needs immediate medical attention.  The rule is to remove the caterpillar immediately without rubbing the affected area. One who is  particularly sensitive to higad must get immediate help.    
Tussock moth caterpillars are passive and tend to group together. Before they enter pupal stage they descend from their host tree, hide in crevices, and other suitable places where they will later emerge as moths.

Tussock moth caterpillars in three stages (instars), pupa (left, scantily covered with cocoon thread), molted skin (lower left), and frass or waste (right).
Snowy tussock moth mimic the color and pattern of its host tree, and growing lichens.

Tussock moth - a master of camouflage. It can adjust to the color and pattern of its environment.

First aid: Train melted candle over embedded bristles, then carefully peel off. Apply vinegar on the affected area to dissolve remaining bristles. Do not rub.

NOTE: Skin castings of higad can inflict considerable injury. Eliminate castings by burning or burying, just as caterpillars are disposed off. Higad may inflict the same injury on pets. Regular smudging (smoke emitted by burning dead leaves) can effectively reduced higad population. Household insecticide spray can help. Community control using chemicals needs expert's assistance.

1 comment:

Mon said...

Just apply vinegar and the urticaria will disappear in seconds. I am a nurse and I know this for a fact.