Pieris brassicae (L.)
Common name: Large cabbage white.
Taxonomic placing: Insecta, Holometabola, Lepidoptera, Pieridae.
Morphology: The adult is about 20 mm long, the forewings are white with 1-2 round black spots and a large anterior black area, hindwings with an anterior black spot. The larvae are hairy, green-grey with black dots and yellow lateral stripes, the head is blackish, body length up to 40 mm.
Geographical distribution: Europe, North Africa and Asia.
Host plants: Members of the family Brassicacae
Life history: The females place their eggs (about 200/female) in groups on the lower side of host leaves. The hatching larvae are gregarious and feed on the leaves, often completely skeletonizing them. The mature larvae move onto stems or even trees to pupate, being held by a silken band. About 400 day-degrees are required to complete a generation, and the pest raises 3-5 annual generations, depending on the region. Due to its sensitivity to high temperatures, P. brassicae occurs in the Middle East only in the cooler autumn and winter months. It is a strong flier and can migrate over long distances; in the Middle East its populations are probably augmented annually during autumn.
Economic importance: Larval feeding on various Brassicaceae, although sometimes localized, may lead to 100% crop loss in certain areas at certain times. Due to the market value of the host plants (such as Brussels sprouts, cabbage, rape and turnips), which are sold for consumption, damage may greatly reduce the crop value. Pieris brassicae is considered a pest in many European and Asian countries. In India and Turkey it annually causes over 40% yield losses of various vegetables.
Management
Chemical control: Pyrethroids were very effective in controlling the pest in India.
Biological Control: Several natural enemies attack P. brassicae In different regions. The parasitoids Cotesia glomerata (Braconidae) and Pteromalus puparum(Pteromalidae) killed about half the pest population in Iran. Other important enemies are Anilastus ebeninus (Gravenhurst) (Ichneumonidae) and Phryxe vulgaris (Fallén) (Tachinidae). A commercial product of Bacillus thuringiensis and Entomopathogenic fungi caused about 20% pest mortality.
References
Feltwell, John. 1982. Large White Butterfly: The Biology, Biochemistry, and Physiology of Pieris brassicae (Linnaeus) The Hague: W. Junk.
Gardiner B.O.C. 1978. Instar number and pupal colouration in Palaestinian Pieris brassicae. Proceedings and Transactions of the British Entomological and Natural History Society 11: 21–23.
Prabhakar, A. and Bishop, A.H. 2009. Effect of Bacillus thuringiensis naturally colonising Brassica campestris var. chinensis leaves on neonate larvae of Pieris brassicae. Journal of Invertebrate Pathology 100: 193-194.
Razmi, M., Karimpour, Y., Safaralizadeh, M.H. and Safavi, S.A., 2011. Parasitoid complex of cabbage large white butterfly Pieris brassicae (L.) (Lepidoptera, Pieridae) in Urmia with new records from Iran. Journal of Plant Protection Research 51: 248-251.
Thakur, N.S.A. and Deka, T.C, 1997. Bioefficacy and economics of different insecticides against Pieris brassicae (L.) on cabbage in midhills of North-East India. Indian Journal of Plant Protection 25: 109-114.