Efficacy of different neem (Azadirachta indica) products in comparison with imidacloprid against English grain aphid (Sitobion avenae) on wheat
2013
Aziz, M.A. (PMAS Arid Agriculture Univ., Rawalpindi (Pakistan)) | Ahmad, M. (PMAS Arid Agriculture Univ., Rawalpindi (Pakistan)) | Nasir, M.F. (PMAS Arid Agriculture Univ., Rawalpindi (Pakistan)) | Naeem, M.
Different neem (Azadirachta indica L.) extracts (leaf and seed) and seed oils were tested against English grain aphid (Sitobion avenae F.) with a neonicotinoid, imidacloprid on wheat. All neem oils and neem seed kernel extract proved comparatively more effective in laboratory bioassay studies, with LC50 values ranging from 0.34 to 1.10%. In field-cage experiment, neem xedoil-hexane was statistically similar with imidacloprid followed by neem seed oil-expeller and neem seed kernel extract, while neem seed oil-ethanol was at par with imidacloprid. On the basis of cumulative insect days in field trials, neem seed oil-expeller proved as effective as imidacloprid in controlling the aphids, while except neem seed cake extract, all other treatments were statistically at par with imidacloprid. Non-significant differences were found in the population of mummified aphids between control and neem seed kernel extract, neem leaf extract, neem seed oil-hexane, neem seed cake extract and neem seed oil-expeller. There existed non-significant differences in all treatments regarding aphid predators. Maximum increase in wheat yield (7.28 q/ha) was observed in neem seed kernel extract treated plots followed by those of imidacloprid (7.23 q/ha). Application of imidacloprid resulted in maximum cost-benefit ratio (1:1.34) followed by that of neem seek kernel extract 5% (1:1.31). If the additional cost of loss of beneficial organisms and environmental risks posed by the application of synthetic insecticides is considered, the cost-benefit ratio of neem seed kernel extract may be comparable to that of imidacloprid and may be used against wheat aphids.
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