Homona coffearia (tea tortrix)

Larvae of H. coffearia feed on leaves, especially at the growing points of plants. Leaves are webbed together in larval nests which eventually become blackened masses of leaf fragments, silken threads and caterpillar frass. The larvae do not eat the whole leaf, but nibble at random. The leaf nest has several holes and appears blackened and untidy. Areas affected by H. coffearia have a bronzed appearance when viewed from a distance.

Biological Control

The parasite Macrocentrus homonae was introduced to Sri Lanka from Java in 1935-36 and has reduced H. coffearia to an occasional and local pest there (Cranham and Danthanarayana, 1971). H. coffearia is the only known host of M. homonae (Mills and Carl, 1991), which has also been used successfully to control the tea tortrix in India (Chacko, 1987; Selvasundaram and Muraleedharan, 1987). A series of trials were conducted on the egg parasitoid Trichogramma erosicornis to control H. coffearia in Sri Lanka, but the results of this were not encouraging (Tamaki, 1991).

The pest is well controlled in the highlands of New Guinea by two ichneumonid parasitoids, Theronia simillima and Camptotypus (Hemipimpla) clotho.

Chemical Control

Aminocarb, fenitrothion and formothion have been found to be effective in controlling H. coffearia (Tamaki, 1991). Unfortunately, chemical control against the tea pest Xyleborus fornicatus has actually caused outbreaks of H. coffearia in Sri Lanka by destroying its natural enemies (Cranham and Danthanarayana, 1971).

H. coffearia was a major pest of tea from 1910 to the 1930s in Sri Lanka, but the introduction of the parasitoid Macrocentrus homonae from Indonesia was very successful and reduced H. coffearia to the status of a minor seasonal pest. However, the importance of this pest has increased since the mid-1950s because insecticides used to control the shot-hole borer Xyleborus fornicatus have destroyed the natural enemies of H. coffearia.