Alguns aspectos químicos envolvidos na interação Hypsipyla grandella (broca-do-mogno e Swietenia macrophylla (Mogno)

Abstract

The interaction between Hypsipyla grandella (Mahogany bore) and Swietenia macrophylla was studied in order to understand the chemical and ecological aspects involved on this process. H. grandella is a shoot borer lepdoptera which attack the shoots of the mahogany causing serious economic problems for large scale plantation of this trees. In this work, it was done biological tests with Spodoptera frugiperda and Anticarsia gemmatalis, using the crude extracts from mature leaves against. The ethyl acetate extract, which is composed basically by flavonoids, showed the best activity, killing ali A. gemmatalis larvae. The flavonoids from the S. macrophylla mature leaves were: quercetin (1) and three glycosiled flavonoids with quercetin skeleton substituted by rhamnose (2) glucose (3) and galactose (4) in the 3 position. The compounds were also tested against larvae of the H grandella, which showed toxicity to its larvae. Terpenoids isolated from down part of graft of Cedrela- Toona, was submitted to same test and the results obtained showed the same activity. As the borer attacked only the shoots, eletroantenographic studies were performed in order to determinate if the oils involved in this interaction exercise some kind of olfactory onentation on the process to choice the host plant for this lepidoptera. In the eletroantenographyc study were used volatile oils from the young shoots, mature leaves and senescent leaves of the S. macrophylla. The young shoots showed high electrophysiological responses and the female antennas showed better responses than the male one. The main compounds of the young shoot, mature leaves and senescent leaves were studied by LC/MS. Observations in large scale plantations showed that mahogany trees from the same place, but with origin from different place showed different attacks from the H grandella. The volatile oils from mahogany of different origin were studied, however no correlation was observed.