Aphis gossypii Glov. - Cotton Aphid
Synonym.Aphis cucumeris Fobes., A. cookii Essig., A. citri Essig., A. cucurbitae Buckt., A. tectonae Goot.
Systematic position.Class Insecta, order Homoptera, suborder Aphidinea, superfamily Aphidoidea, family Aphididae, subfamily Aphidinae, tribe Aphidini, subtribe Aphidina, genus Aphis.
Biological group.Polyphagous pests.
Morphology and biology.Ovoid prominent body of apterous female is yellow-green or dark green with yellow legs. Yellow 6-segmented antenna is 3/4 the body length. Apices of femora and tibia, and tarsi are entirely black. Cylindrical black siphunculi are slightly expanded at base, 1/5 the body length, 1.7-2 times as long as tail. Prothorax, 1st and 7th abdominal segments have small marginal tubercles. The body of winged female is fusiform. Head and thorax are black, abdomen is yellow-green with black lateral spots. Antenna is longer than that of apterous female. Oval eggs are black. Overwintering takes place at the adult stage on wild plants of different families. Awakening occurs in April-May. At-first, the aphids feed on weeds; in May or the beginning of June, they migrate to agricultural cultures, such as cotton, melons, cucumber, squash, aubergine, and others. Insects live on the lower side of leaves, on flowers and fruits. During this period, the aphid number is numerous; they form large colonies. Life span of parthenogenetic female is about 17-22 days; multiplication period lasts two weeks. Fecundity approaches 85 larvae. The larval period lasts 6-9 days. In July and the beginning of August, the aphid number decreases, then increases again until the end of August. On cotton, the pest develops until the first frost, and then it migrates to wild plants.
Distribution.Species is spread in Europe; Anterior and Middle Asia; North and South America; Africa and Australia. Within the territory of the Former Soviet Union, the species occurs northward to 54°N. The Cotton Aphid is found in West Siberia. Its harmful activity is reported in steppe zone of Ukraine, in the North Caucasus, Middle Asia, Kazakhstan, Transcaucasia, Middle and Lower Volga Basin region. Highest harming activity is marked in Middle Asia, Azerbaijan, South Kazakhstan, Lower Volga Basin region.
Ecology.Larva hatching is observed in spring at the degree day sum of temperatures 140-150°C. The insect large population is marked at the DD 1000-1100°C. Under snow covering, the aphid endures frosts to -15°C; in spring, it can perish at temperature -5°C (at high humidity). The most favorable conditions for insects are the temperature 16-22°C and humidity 60-80%. Temperatures above 25°C have unfavorable effect on the pest. Therefore, the species is usually depressed in southern regions of its area in July and the beginning of August. The pest gives 22-27 generations during a year. Most important predators are Orius niger Wolff., Nabis ferus L., N. feroides Rem., Adalia bipunctata L., Propylaea 14-punctata L., Coccinella septempunctata L., C. 14-pustulata L., Adonia variegata Goeze., Scymnus frontalis Fabr., Chrysopa perla L., Ch. carnea Steph., Syrphus corollae F., S. balteatus Deg., S. ribesii L., Aphidius cardui Marsh., Praon abjectum Marsh.
Economic significance.The species is a wide polyphage. It damages cultural and weed plants of the families Rosaceae, Chenopodiaceae, Malvaceae, Cruciferae, Cucurbitaceae, Solanaceae, Compositae, and others. Its highest harming activity is observed on cotton. Aphids populate young tender leaves, which become yellow and dry up. Damaged shoots do not give flowers and fruits. Melons, solanaceous plants, cucumber, and pumpkin can also be strongly damaged. The Cotton Aphid transfers virus diseases. During large numbers, the yield may decrease by 22-56%. Control measures include eradication of weeds, insecticide treatments in May and June on cotton, cucumber, melons, and other cultures.
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Davletshina A.G. 1952. To problem of cotton aphid overwintering. In: Abdullaev Kh.M., ed. Proceedings of AN Uz. SSR. N 1. Tashkent: AN Uz.SSR. 45-47 p. (in Russian).
Ivanovskaya O.I. 1976. Fauna of aphids on the territory of West Siberia. In: Zolotorenko G.S., ed. Fauna of helminthes and arthropods of Siberia. Novosibirsk: Nauka. P. 175-189 (in Russian).
Karpova A.N. 1937. Development and distribution of cotton aphid within the cotton regions. In: Volkov V.F., ed. Survey of pests and diseases development on agricultural crops during 1936. Leningrad: VASKhNIL, 260-271 p. (in Russian).
Kosov V.V., Polyakov I.Ya., ed. 1958. Forecasting and registration of pests and diseases on agricultural crops. Moscow: Agricultural Department. 341 p. (in Russian).
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Mamaev K. 1966. Cotton aphid. Zashchita rastenii 6: 50 (in Russian).
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Migulin A.A. 1983, ed. Agricultural entomology. Moscow: Kolos. 162-163 p. (in Russian).
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Nosova T.M. 1978. Influence of meteorological conditions on cotton aphid development. In: Ivannikov V.F., ed. Selection and plant protection (Proc. of Ul'yanovsk SKhI). Kuibyshev: Ul'yanovsk SKhI. 24-28 p. (in Russian).
Nosova T.M.1980. Cotton aphid as cucumber pest for open soil in forest-steppe zone of Middle Volga Basin region. PhD Thesis. Khar'kov: Khar'kov SKhI. 14 p. (in Russian).
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Uspenskii F.M., Solov'eva A.I. 1956. Pests and diseases of cotton. Cotton-growing. Tashkent: Gosizdat Uz.SSR. p. 270 (in Russian).
Vasil'ev I.V. 1922. To problem of overwintering of cotton aphid (Aphis gossypii Glov.) in southern regions of Russia. In: Pospelov V.P., ed. News of entomological applied department. Vol. 2. Petrograd. Experimental agronomy institute. 16-20 p. (in Russian).
Vasil.ev V.P., ed. 1973. Pests of agricultural crops and forest plantations. 1. Kiev: Urozhai. 284 p. (in Russian).