Earias insulana (Boisduval)

Taxonomic placing: Insecta, Holometabola, Lepidoptera, Noctuidae .

Common name: Spiny bollworm, Egyptian bollworm.

Geographical distribution: The pest occurs around the Mediterranean and in Africa. CIE map #251.

Host plants: The spiny bollworm is oligophagous on (Malvaceae), including cotton and okra (Hibiscus esculentus Linnaeus).

Morphology: The forewings of the adult moth are yellow-green or sometimes brown, with a diagonal green stripe. resumably these color morphs are seasonal, representing local adaptations to ambient heat, humidity and foliage density. The hindwings are dull white with a brown subterminal line. The larva is initially grey, later grey-blue with yellow spots, its dorsum with small tubercles bearing short hairs. The head is dark and shiny and the final length is 15-18 mm.

Life cycle: Each female deposits up to about 150 eggs at 25-28°C on host plants. The larvae of the first generation bore into terminal cotton buds, those of later generations into flower buds, flowers and newly-set bolls. Larval development can take 3 weeks during summer, require twice as long at 19°C. The mature larva spins a white cocoon, attaches it to plant parts and pupates therein. The pest develops all year around in the Eastern Mediterranean region, without a winter diapause. During winter it lives on cultivated shrubs like Hibiscus spp.. It may raise up to six annual generations in the Middle East, one per month in summer. Being a specialist, the size of its populations is restricted by the availability of various Malvaceae, especially cotton.

Economic importance Earias insulana is a major pest of cotton in the Eastern Mediterranean. Damage is caused by the larvae, which cause bud and flower withering. The pest prefers the developed cotton bolls, especially the nutritious seeds. Infestations of maturing bolls injures the developing filaments, concurrently introducing bacterial and fungal agents. After depleting the finitial boll, the larvae move to other cotton plants, penetrating new bolls. A heavy attack may destroy the entire crop.

Management

Monitoring: Following moth population trends by female sex-pheromone traps, in order to determine the best dates for chemical control.

Horticultural method: Burning or plowing cotton fields to a depth of 30 cm or more, in order to destroy all residual material and any pests remaining thereon after harvest.

Chemical control: The bollworm has developed resistance to most of the chemical insecticides. Neem formulations, IGRs or Bacillus thuringiensis (Bt) can be applied against the pest within an IPM program.

Mating disruption: This approach may also be part of the IPM program.

Transgenic methods: Cotton varieties that express the Bt toxin controlled the pest in Egypt.

Biological control: Egg parasitoides reduce pest populations, but they are often killed by the extensive use of chemical pesticides. Coccinellidae are the more important predators in Syria early in the cotton season (June-July), whereas Hemipteran predators occur in large numbers during August and September.

References

Dahi, H.F. 2012. Field performance for genetically modified Egyptian cotton varieties (Bt cotton) expressing an insecticidal-proteins Cry 1Ac and Cry 2Ab against cotton bollworms. Nature and Science 10: 78-85.

Horowitz, A.R., Klein, M., Yablonsky, S. and Ishaaya, I. 1992. Evaluation of benzoylphenyl ureas for controlling the spiny bollworm Earias insulana(Boisd.), in cotton. Crop Protection 11: 465-469.

Kandil Mervat, A.A. 2013. Relationship between temperature and some biological aspects and biochemical of Earias insulana (Boisd.) (Lepidoptera: Noctuidae). Egyptian Academy Journal of Biological Sciences 6: 11-20.

Klein, M. 1988. Color morphs induced under controlled environmental conditions in adult Earias insulana (Lepidoptera: Noctuidae). Environmental Entomology 17: 162-165.

Meisner, J., Klein, M. and Keren, S. 1990. Effect of Margosan-O on the development of Earias insulana. Phytoparasitica 18: 287-297.

Nakache, J., Dunkelblum, E., Kehat, M., Anshelevich, L. and Harel, M. 1992. Mating disruption of the spiny bollworm, Earias insulana (Boisduval) (Lepidoptera: Noctuidae), with the Shin Etsu twist-tie rope formulation in Israel. Bulletin of Entomological Research 82: 369-373.

Navon, A., Keren, S., Levski, S., Grinstein, A. and Riven, Y. 1997. Granular feeding baits based on Bacillus thuringiensis products for the control of lepidopterous pests. Phytoparasitica 25 (supplement): 101S-110S.

Stam, P.A. and Elmosa, H. 1990. The role of predators and parasites in controlling populations of Earias insulana, Heliothis armigera and Bemisia tabaci on cotton in the Syrian Arab Republic. Entomophaga 35: 315-327.

Website: https://www.google.co.il/search?q=eriosoma+lanigerum&biw=1024&bih=695&tbm=isch&tbo=u&source=univ&sa=X&ved=0CBoQsARqFQoTCLaPq_HFxsgCFYNEFAodlgoNmg#tbm=isch&q=earias+insulana http://en.wikipedia.org/wiki/Earias_insulana