| dc.description.abstract | Volatiles released from maize (in-bred A) and sorghum (serena' cultivar) seedlings
which Chilo partellus attack were trapped on three solid adsorbents: reverse phase, Porapak
Q and charcoal. The trapped organic volatiles were then eluted into vials using
dichloromethane as the solvent. The eluted aliquots were concentrated by blowing a stream
of nitrogen gas and analyzed on GC and GC-MS, packed with methyl silicone column and FID
detector. The compounds identified from Zea mays were: toluene 4.4(%, octanal 0.7<%,
nonanal 2.9%, (3 E)-hexenyl acetate 3.7%, cis-dihydro carveol, 1.4%, (3E)-4,8-dimethyl1,3,7-nonatriene,
21.4%,decanal, 3.2%, 3-eicosene 1.0%, copaene 41.8%, zingiberene, 6.8%,
a-bergamotene, 3.7%, 8-Cedrene, trace, cis-caryophyllene, 26.4%, B-caryophyllene 4.1%,
(a+B)-humulene 2.5%, a-amorphene 0.8%, patchoulene 2.3%, l-chloro hexadecane, 5.1(Yo,
lidol 2.7%, cadinene 6.9%, y-cadinene, 0.9%, a-Farnesene trace, B-springene 8.8%,
( caryopbyllene oxide 1.0%, , l-pentacontanal 2.1%, and 12 compounds identified from
Sorghum bicolor seedlings were: octanal 0.9%, decanal 9.3%, octadecanal 1SYO, transcaryophyllene
31.5%, B-farnesene 1.9%, B-humulene 0.9%, tridecanal 1.6%, l-pentacontanol
1.7%, cedroI2.4%, 2-hexyldecanol, 2.3%, 3,7,II-trimethyl-2,6,10-dodecatrienol 1.5 %, and
bis-(2-methoxyethyl)phthalate 29.4%.
Active compounds for each sample were determined usmg Gas chromatography
coupled with electro-antennal detector (GC-EAD) technique, Sorghum bicolor sample
showed one weak active peak corresponding to bis (2-methoxyethyl) phthalate 29.4%, while
Zea may's sample showed 5 active peaks corresponding to (3E)-4,8-dimethyl-l,3, 7-nonatriene
21.4 %, cis-caryophyllene 26.4%, l-chloro hexadecane 5.1 %,a-farnesene trace, B-springene
8.8%. Among the identified compounds, (3E)-4,8-dimethyl-l ,3,7-nonatriene, caryophyllene
andcc-famesene have been found to be attractive to the insect pests.
Thus odours emanating from these crops may playa role in the orientation of its insect
pests towards the plants and in ultimate recognition of the host plant for feeding and
oviposition. To contribute towards this vital knowledge the composition of Zea mays and
Sorghum bicolor volatiles were determined in the most natural state of the plant as possible.
This meant that artifacts due to root or leaf damage were to be avoided as much as possible by
using whole plant (no root or leaf cutting was done). It was also necessary to trap volatiles
released at night in order to ascertain why Chilos attack these plants at night. | en |
