Biological Control of Insect Pests: Southeast Asian Prospects - EcoPort

318 Biological Control of Insect Pests: Southeast Asian Prospects
Trichoplusia ni (HŸbner)
Rating
Origin
Distribution
Biology
Lepidoptera: Noctuidae
cabbage looper
Synonym: In North America T. ni has sometimes been referred to
as Autographa brassicae (Riley).
Southeast Asia China
7 ++ Myan, Thai, Camb + (all 14 southern Provinces)
+ Viet
P Indo
T. ni is native to the southern half of North America.
Widespread in southern Europe, North, East and South Africa, extending
eastwards through Pakistan, India and Bangladesh to much of Southeast
Asia, to China, Taiwan, Korea and Japan; not yet present in Papua New
Guinea, Australia, New Zealand or the oceanic Pacific; present in South
America in Argentina, Bolivia, Brazil, Chile, Colombia and Uruguay
(Apablaza and Norero 1993; CIE 1974b). In North America, T. ni
overwinters in the south, re-invading northern States each spring.
Adult T. ni are mottled brownish in colour. The forewings, producing a span
of about 3.8 cm, each bear an 8-shaped silvery mark near the middle. Adults
are mostly active at night, but also on dull days. By day, they rest on the
underside of host plants, in the debris at their base, or in vegetation bordering
a cultivated crop. Adults are capable of flying long distancesÑ700 km
northwards from southern Texas (Lingren et al. 1993) 161 km from land into
the Gulf of Mexico, and up to 1500m in California (Kreasky et al. 1972).
They move readily between cultivated and wild hosts. A female may lay
her own bodyweight in eggs, but requires access to nectar and moisture to do
so. After emerging from the pupa, there is a pre-ovipositional period of about
4 days, after which mating begins and can occur up to 16 days. A female may
produce well over 1000 viable eggs. Peak egg deposition is often correlated
with the lunar cycle, a rapid rise in egg density on cotton occurring shortly