Scrobipalpa ocellatella Boyd
Common name: Beet moth.
Taxonomic placing: Insecta, Holometabola, Lepidoptera, Gelechiidae.
Geographic Distribution: The Mediterranean region, the Canary Islands, most of Europe, the Middle East, Iran, southern European Russia, Ukraine, Moldova, Georgia and Turkmenistan
Host plants: Several Amaranthaceae, and especally several species of Beta (like B. vulgaris L.), Atriplex and Amaranthus.
Morphology: The body of the adult is 5-7 mm long, the forewings are narrow, elongated, grey-brown, with several rounded dark spots, the hindwings are light grey and have long posterior fringes. The larva (caterpillar) is initially greenish, later becoming red-pink with several red-brown longitudinal lines; head brown, length 10-12 mm.
Life history: Females lay about 40-70 eggs (up to 200) each on the host leaves. The young larvae bore in the leaf mirdrib and the petiole of these leaves, then in the root, wherein they form irregular galleries lined with a silken web. They pupate in any available dry sites, being very sensitive to high relative humidity. The threshold of development is around 10°C, the adults may live for about weeks and the pest raises four annual generations.
Economic importance: Regarded as a serious pest of sugar beets in Syria and in Iran, especially when infesting seedlings. Their leaves may roll, become distorted and blackish; weak plants turn yellow and wilt. Flower buds may also be damaged. Heavily infested sugar beets lose up to 24% of their sugar content and the plants may further be damaged by invading pathogens. Sugar beets and fodder beets suffer more than red garden beets.
Management
Monitoring: Pheromone traps have been used for monitoring the flight pattern of the pest and for timing of control measures.
Horticultural control: High relative humidity, achieved with overhead irrigation, protects sugar beet from the humidity-susceptible pest.
Plant tolerance: Some Egyptian sugarbeet cultivars appear to be relatively tolerant to the pest.
Chemical control: An aqueous extract of chestnut (Castanea sativa Mill.) leaves sprayed on sugar beet leaves, repels the pests, inhibits their oogenesis and oviposition. Organophosphates applied in Iran controlled the pest.
Biological control: .Caterpillars and pupae are attacked by endoparasitoid braconids, like Chelonus sulcatus Jurine, which in some years kills 45-60% of the pest population, Bracon intercessor Nees and Microchelonus subcontract Abdinbekova. Releases of the egg parasitoid Trichogramma evanescens Westwood (Trichogrammatidae) in sugar beet plots in Egypt reduced pest damage by up to 95%.
References
El-Dessouki, S.A., EI-Awady, S.M., El-Khawass, K.A.M.H., Mesbah, A.H. and El-Dessouki, W.A.A. 2014. Population fluctuation of some insect pests infesting sugar beet and the associated predatory insects at Kafr El-Sheikh Governorate. Annals of Agricultural Science 59: 119–123.
El-Rawy, A.M. and Shalaby, G.A. 2011. Reaction of some sugarbeet varieties
To the infestation with some insects and final yield. Egyptian Journal of Agricultural Research 89: 1383-1391.
Hammad, S. M., Youssef, K. E. H. and Assem, M. A. H. 1968. The biology of the sugar-beet mining moth Scrobipalpa ocellatella (Boyd) (Lepidoptera: Gelechiidae). Bulletin de la Société Entomologique d’Égypte 52: 49-51.
Mahmoudi, J., Askarianzadeh, A., Karimi, J. and Abbasipour, H. 2013. Introductiion of two parasitoids of braconid wasps on the sugar beet moth,, Scrobipalpa ocellatella Boyd.. (Lep..: Gelechidae)) from Khorasan–e–Razavi province, Iran. Journal of Sugar Beet 28: 103-106.
Naeem, A. 1977. Effects of some phosphorous insecticides on sugar beet moth in Esfahan area. Entomologie et Phytopathologie appliquées 45: 41-45.
Renou M., Descoins, Ch., Lallemand, J.Y. Priesner, E., Lettere, M. and Gallois, M. 1980. L’acétoxy-1 dodecène 3E, composant principal de la phéromone sexuelle de la teigne de la betterave: Scrobipalpa ocellatella Boyd. (Lépidoptère Gelechiidae). Journal of Applied Entomology 90: 275-289.
Robert, P.Ch. 1976. Inhibitory action of chestnut-leaf extracts (Castanea sativa Mill.) on oviposition and oogenesis of the sugar beet moth (Scrobipalpa ocellatella Boyd; Lepidoptera, Gelechiidae). In Jermy, T. (Ed,) The Host-Plant in Relation to Insect Behaviour and Reproduction, Plenum Press, New York and London, pp. 223-227.
Shahira S.M. 2004. Use of the egg parasitoid Trichogramma evanescens West. for controlling the rib miner, Scrobipalpa ocellatella Boyd in sugar beet in Egypt (Lepidoptera: Gelechiidae). Egyptian Journal of Biological Pest Control 14: 2.