MARCIA MARZAGÃO RIBEIRO INFLUÊNCIA DA ADUBAÇÃO ...

INFLUENCE OF NITROGEN FERTILIZATION ON OCCURRING OF AMPOLA
Gyropsylla spegazziniana (Hemiptera Psyllidae) OF MATE-TREE
The mate-tree one of the main crops in South Brazil is drinked for a long time by the
Tupi-Guarani Indians. Is a plant with particular requirements of soil characteristics,
foliar composition, and an interesting beverage consumed mainly in Brazil, Argentina,
Paraguay and Uruguay. The leaves and the stems are the final product, that should be
free from impurities as fragments of insects, animals and pesticide residues; their
leaves should contain the minerals that turns it nutritional and medicinal valuable. The
nutrients of the plant are intercepted by the insect that redirects it to alimentary chain.
One of the nutrients is nitrogen, in form of free amino-acid, in the sap of the phloem
that participates in the formation of their own proteins and consequently, of the
chemical composition of the exoeskeleton of the insects. The objective of this research
was to study the relationships between the mineral nutrition of mate-tree with the
insect Gyropsylla spegazziniana a specific pest of the plant. The resistance of the plant
could be improved through the induction of a nutritional-balance. The experiment was
developed in three different areas, in plants with different ages and different
morphotypes. The fertilization with triple-superphosphate, potassium-chloride and
ammonium-sulfate as treatment of 03 levels. The damage of the insect in the plants
was counted during the spring-summer period. As a method of diagnosis of the
nitrogen-insect relation foliar analysis procedure was performed, considering the
sanity, productivity and nutritional quality leaves. Was observed the influence of the
ammonium-sulfate as for the attack of Gyropsylla spegazziniana and also the biomass.
The incidence of the insect in the morphotypes there was not significant difference (p
< 0,10) however, in percentage, the amarelinha morphotype obtained smaller damage,
with 21,8% than cinza morphotype, 15,8% than the sassafrás morphotype. It was
ended that the levels of 200 kg and 300 kg of ammonium sulfate per hectare, for 1667
plants, per hectare (2,5 and 3,5 of age), were the most promising doses for biomass
production but caused a larger amount of damage by insect.
Key words: pest, nitrogen fertilizer, foliar composition.
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