| Abstrakt: |
The cardiac glycoside, digitoxin, from Digitalis purpurea L (Scrophulariaceae), a cardiac glycosidal (cardenolide) extract from Calotropis procera (Ait) R Br (Asclepiadaceae), azadirachtin and neem oil from Azadirachta indica A Juss (Meliaceae) were tested for their effects against larvae and adult stages of the camel tick, Hyalomma dromedarii Koch (Acari: Ixodidae). The contact LC[sub50] values of the first three materials against adults were 4.08, 9.63 and >40.7 µg cm][sup-2], respectively, whereas the dipping LC[sub50] values of the four materials were 409.9, 1096, > 5000 and > 5000 mg litre[sup-1], respectively. Contact and dipping LC[sub50] values of the extract and azadirachtin against larvae were 6.16, >20.3 μg cm[sub-2] and 587.7 and >2500mg litre[sup-1], respectively. Azadirachtin had no effects on egg production or feeding of adults up to 5000mg litre[sup-1]; however at 2500mg litre[sup-1], it caused significant reduction in feeding activity of larve, prolonged the period for moulting to nymphal stage, and caused 60% reduction in moultability. Results of the two cardiac glycoside materials are comparable with those of several commercial acaricides. The risks and benefits associated with the use of cardiac glycosides are considered. [ABSTRACT FROM AUTHOR] |
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