| Country or region name |
Japan |
| Organism group |
insect |
| Order name |
Lepidoptera |
| Family name |
Pieridae |
| Species name |
Pieris brassicae |
| English common name |
large white butterfly, large white |
| Substantially same species (synonym) |
|
| Year of invasion or detection |
1996 |
| Native region |
Europe |
| Situation of establishment |
Category 4: Settled after 1951, but not distributed all over the
country |
| Taxonomic description |
| |
| Expansion of distribution area |
| The first one (male) of the large white butterfly was collected
in 1995 in Hokkaido. And many individuals (males and females) were collected
in 1996. The butterfly was estimated to immigrate from the Continent into
Hokkaido by flight. The distribution area was restricted in southeastern
and coastal regions along Japan Sea until 1997. This species has high ability
for long dispersal (Imamura,1990; Hachiya,1997; Sakanouchi,1997).
The large white butterfly expanded widely in the southeastern region of
Hokkaido in 1996 just after invasion, and was found in August of 1996 in
the Shimokita and the Tsugaru Peninsula of Aomori Prefecture in Tohoku
district (Hachiya, 1997; Kimura,1997). Recently, the distribution area
of the large white butterfly expanded almost all Hokkaido district (Ito,
personal communication) and Iwate Prefecture in Tohoku district in 2004
(MAFF Pest Forecasting information). This butterfly is well known as a
migrant longer than 400 km (Sakanouchi,1997).
|
| Environmental impact |
| The larvae of the large white butterfly may eat up small colonies
of the wild Brassicae plants and the other plants which contain mustard
oil glycosides, if the adults oviposite many egg masses on those plants.
|
| Economic damage |
| The crowded larvae devour the leaves of Brassicae plants such as
cabbage and Japanese radish. The damage was caused especially by crowded
last instar larvae. But the damage is not seen usually in farmer's vegetable
fields because the chemical control was conducted against diamondback moth.
Only the vegetables in gardens where the chemical control was not conducted
frequently were caused damage by this insect (Hachiya,1997). |
| Reproduction |
| The adults mate after 1-4 days after emergence and oviposit about
60-70 eggs per egg mass (average) on the lower side of host leaves (Hachiya,1997).
The total number of eggs oviposited per female was 750 in the laboratory
(Gardiner, 1974). |
| Growth |
| The larvae grow up to 5th instar within 2-8 weeks under natural
temperature. The eggs are oviposited as egg masses and the larvae are found
in crowded on the upper side of the leaves. This species is very resistant
to low temperature. Diapause pupae can survive for 30 days at -30C (Sakanouchi,1997).
|
| Countermeasure |
| This insect pest attacks Brassicae crops. Farmers can control this
insect pests together with the diamondback moth,Plutella xylostella by chemical application. The chemicals such as organophosphorous, synthetic
pirethroids and BT are effective to the larvae (Hachiya,1997). The larvae
usually exist on the upper side of the leaf and are easy to control by
spraying chemicals. |
| Writer's name and affiliation |
| © Masaharu Matsui. National Institute for Agro-Environmental Science
(Updated on 22, Oct. 2004) |
