Journal of Economic Entomology (1995) 88, 1024-1031

Y.S. Xie, P.G. Fields and M.B. Isman (1995)
Repellency and toxicity of azadirachtin and neem concentrates to three stored-product beetles
Journal of Economic Entomology 88 (4), 1024-1031
Abstract: Repellency and toxicity of azadirachtin (98% AZA, which contains 98% azadirachtin) and 3 neem extracts (48, 23, and 7% AZA) to 3 stored-product insects, the rusty grain beetle, Cryptolestes ferrugineus (Stephens), the rice weevil, Sitophilus oryzae (L.), and the red flour beetle, Tribolium castaneum (Herbst), were investigated in the laboratory. Each test material repelled all 3 species in a standard repellency test using a food preference apparatus. Significant negative correlations were found between insect settling response and extract concentrations. T. castaneum was more sensitive to the repellent action of neem than the other 2 species. The test materials were also toxic to the 3 pest species, with C. ferrugineus being the most susceptible. Six-week LC₅₀ values for 48, 23, and 7% AZA for C. ferrugineus were 18.8, 37.0, and 127.3 ppm, respectively. The F₁ adults of all 3 insect species in almost all treatments were significantly reduced compared with controls. This reduction was significantly dose dependent. The relationship between bioactivity of neem materials and their azadirachtin content was established and is discussed. We confirmed that azadirachtin was largely responsible for both repellent (behavioral) and toxic (physiological) actions of neem on stored-product insects. However, the neem extracts are slightly more active than pure azadirachtin when applied at equivalent azadirachtin concentrations, indicating that azadirachtin is not the only active compound in neem.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Murray B. Isman, Paul G. Fields

Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tribolium castaneum
	Sitophilus oryzae
	Cryptolestes ferrugineus