Abstract only

Cereal aphid (Schizaphis graminum Rond.) damages leaves, ears, cob and sultan of maize. Damaged leaf spottes yellow, stops its growth, twists and perishes in case of strong damage. By anatomic investigation of damaged wheat leaf veins, we obtained a clear picture of damage characteristics: aphid inserts proboscis in those places of veins where it meets less resistance, particularly, where there is no any mechanical tissue (parenchyma). It is important, that cellular line is less here and proboscis of the pest easily reaches fiber tissue. In vein tissues it is easy to notice damage point, as each damaged cell of the tissue is dyed in yellowish- brown color. It must be noted, that damaged cells cover do not dissociate for a long time and is notable as more dark-colored as compared to brown-like background. As a result of aphid damage cell of leaf soon loses its content and perishes, as to the cover it remains on the cell for a long time. Dissociation of the cover takes place only in case of strong or after prolonged damage. Insertion of the proboscis into tissues of leaf with the purpose to suck out juice of phloem by aphid is followed by dissociation of intercellular substance and destruction of live insides of the cell. As a result of it metabolism is disturbed in the tissues of damaged places and the leaves lag behind of the others in growth and lose natural colour. Such character of damage and anatomic changes decisively influence on negative significance-falls weight of mass, decreases harvest of grain and becomes worse its quality. By carried out investigation it was found out, that Schizaphis graminum aphid in the first place damages wheat, and then maize, barley and oats. Aphid of that species differently damages organs of plant as well (leaf, ear, cob, sultan). Pest is characterized by ability to differentiate genotypes. It was found, that cereal aphid prefers genotypes with thick stems and broad leaves. It was found that quality of maize grain is intluenced by the degree of damage caused by aphid. Data probided by the study cereal of aphid harmfulness suggests the following: .The earlier plants are infected by cereal ap- hid, the lower is their height compared to check and the weaker is the energy of heading. .Plant reaction to damage by cereal aphid is determined by the degree of the damage: .increased share of the empty spikelets in spikes; .decreased grain number per spike (high infection during the booting stage may result in no yield); .increases grain shriveling; .decreased weight of biomass.

English

0409|AGRIS 0401|AL-Wheat Program|AL-Maize Program

Juan Carlos Mendieta

CIMMYT Publications Collection