الفهرس يوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
The aim of this investigation was to prepare some botanical insecticides for aphids and cotton leafworm control in the field and identification of their chemical constituents.
The efficacy of some vegetable oils and their methylated products against the 4th instar larvae of S. littoralis was studied. The methylation process increased the efficiency of two oils, garlic and nigella, and decreased the efficiency of another two oils caraway and cumin. On the other hand, in the case of castor bean oil the methylation decreased the LC90 value from 0.79 to 0.66 while LC50 value increased from 0.16 to 0.34 µl/cm2. Three experiments were conducted to study the joint action of the binary mixtures of vegetable oils and methylated vegetable oils.
The efficacy of four cooked mixture preparations against the 4th larval instar of S. littoralis was studied. The cooked with caraway was the most effective, whereas with black pepper was the least active.
Toxicity of different vegetable oils and some preparations against A. craccivora was studied. Flax was the most effective followed by nigella, thyme, caraway, garlic, cumin and castor bean in the laboratory. The four cooked mixtures were of higher toxic effect than uncooked extracts of garlic or onion extracted by either acetic acid or kerosene.
It is evident from field experiments that high percent reduction in infestation against aphids was obtained with cooked mixture with caraway (99.3%), followed by with pepper and with cumin, comparing with 82.3% for cooked mixture. The uncooked extracts gave lowest percent reduction in infestation than cooked mixtures. Only two treatments gave sufficient reduction in infestation. These were GK + OK 1:1 (89.6%) and (GK) at rate 100 ml/L (89.8%). GA gave lowest percent reduction at the two tested rates of application (20.4 and 36.8%).
The four cooked preparations were subjected to GC/MS analysis to determine and identify their chemical constituents. These four preparations contained fatty acids and their esters, aldehydes, ketones, terpens, benzene derivatives, halogenated and nitrogen compounds with different amounts. Hexadecanoic acid was present in the four preparations with 20.21, 13.64, 11.88 and 9.81% for preparation I, II, II and IV respectively.
Garlic lectin was extracted from garlic bulb and separated on column chromatography. The content of each fraction was identified by using HPLC, spectrophotometer and Gel-electrophoresis.