Evaluation of non-conventional treatments for control of the biting louse (Bovicola ovis) on sheep.
By: Heath AC, Lampkin N, Jowett JH. - Ag.Research, Wallaceville Animal Research Centre, Upper Hutt, New Zealand
A variety of non-conventional treatments was applied to biting louse (Bovicola ovis) infested sheep in order to evaluate ways in which farmers could control the louse infestations and still maintain Organic Production Standards. In one trial, louse scores of sheep shorn but kept dry or wetted by water alone or with water plus detergent were compared with unshorn sheep treated similarly. Shearing alone accounted for a 35.7-66.3% reduction in mean louse scores. Wetting alone either with water or with water and added detergent accounted for a 26.9-65.3% reduction in mean louse scores. The combined effects on mean louse scores of shearing and wetting, as opposed to shearing alone, were statistically significant on two of the three farms at 32-35 days post-treatment. The effects persisted for the duration of the trial (between 48 and 52 days), at which point shearing and wetting with detergent provided 95.3-99.6% control of lice. In a second trial, a range of insecticidal substances considered acceptable by Organic Production Standards, azadirachtin (neem), pyrethrum, soap, were applied to louse-infested sheep and their efficacy compared with that of a commercial formulation of cypermethrin. The sheep treated with azadirachtin and pyrethrum had significantly fewer lice than either the control or soap treated sheep over the 48 days of the trial. Neither azadirachtin nor pyrethrum were significantly less effective than cypermenthrin. Control (reduction in louse score) of 85.0-100% was achieved over the period of the trial. It is concluded that most of the non-conventional treatments evaluated had a useful and cost-effective role to play in reducing louse numbers on sheep for at least 40-50 days. The lack of persistence compared with that obtained with conventional insecticides was the only apparent drawback.

Activity and biological effects of neem products against arthropods of medical and veterinary importance.
By: Mulla MS, Su T. - Dept of Entomology, University of California, riverside 92521-0314, USA
Botanical insecticides are relatively safe and degradable and are readily available sources of bio-pesticides. The most prominent phytochemical pesticides in recent years are those derived from neem trees, which have been studied extensively in the fields of entomology and phytochemistry and have uses for medicinal and cosmetic purposes. The neem products have been obtained from several species of neem trees in the family Meliaceae. Six species in this family have been the subject of botanical pesticide research. They are Azadirachta indica A. Juss, Azadirachta excelsa Jack, Azadirachts siamens Valeton, Melia azadarach L., Melia toosendan Sieb. and Zucc., and Melia volkensii Gurke. The Meliaceae, especially A. indica (Indian Neem Tree), contains at least 35 biologically active principles. Azadirachtin is the predominant insecticidal active ingredient in the seed, leaves and other parts of the neem tree. Azadirachtin and other compounds in neem products exhibit various modes of action against insects such as antifeedancy, growth regulation, fecundity suppression and sterilization, oviposition repellency or attractancy, changes in biological fitness and blocking development of vector-borne pathogens. Some of these bioactivity parameters of neem and veterinary importance, such as mosquitoes, flies, triatomines, cockroaches, fleas, lice and others. Here we review, synthesize and analyze published information on the activity, modes of action, and other biological effects of neem products against orthropods of medical and veterinary importance. The amount of information on the activity, use and application of neem products for the control of disease vectors and human and animal pests is limited. Additional research is needed to determine the potential usefulness of neem products in vector control programs.

SOURCE: J Am Mosq. Control Assoc 1999 Jun; 15(2):133-52
Toxicity of Neem Seed Oil against the larvae of amblyomma variegatum - a three-host tick in cattle.
By: Ndumu PA, George JB, Choudhury MK. - Dept. of Vet. Parasitology & Entomology, Faculty of Vet. Medicine
The in vitro toxicity of neem seed oil (Azadirachta indica, family: Meliaceae, 'Dogon yaro' in Hausa-language) was tested against the larvae of a three-host tick, Amblyomma variegatum (family: Ixodidae or hard tick) parasitic to cattle commonly found in Nigeria. Undiluted neem oil (100% concentration) was found to kill all (100% mortality) the larvae after 48 hrs. The toxicity was concentration and time dependent.

SOURCE: Phytother Res 1999 Sep; 13(6):532-4

In - vitro trials for testing acqricidal properties of a new product Nimbitor
By: M. D. Deore, V.S. Deshpande and V.S. Narsapur - Dept. of Parasitology, Mumbai Veterinary College, Mumbai - 12
In-vitro trials were conducted to test the efficacy of a new Neem oil based insecticide "Nimbitor" against ticks and flies commonly in animals. For ticks Rhipicephalus sanguinus, a dog tick was selected and 10 different concentrations of Nimbitor were tested on engorged females, males and larvae of the dog tick to find out the lethal concentration as well as effect on reproductive behaviour. In case of engorged females, 100% mortality was observed on 9th day after exposure at 16% concentration in males, on 3rd at 8% concentration and within 24 hours at 1% concentration in case of larvae. In engorged females their reproductive behaviour was also severely hampered. The total average egg mass and hatching percent both were significantly lower at 16% concentration as compared to the controls. In case of flies Stomoxys calcitrans sp. was selected and studies were undertaken to find out lethal concentration. Using six different concentrations of Nimbitor, 100% mortality was observed within 24 hours at 2% in 18 hours at 4% in 6 hours at 8% concentration. Hence 8 to 16% concentration can be considered for both ticks and flies.

SOURCE: National Convention of Veterinary Pharmacology & Toxicology,22nd Dec - 1995

Effects of azadirachtin on ctenocephalides felis in dog and cat
By: Guerrini VH, Kriticos CM. - Pestsearch International, Daisy Hill, Australia
Azadirachtin - in neem seed extract is a powerful insect growth regulator, a feeding deterrent and repellent with low toxicity. Unfortunately, azadirachtin degrades rapidly in light, excessive heat or alkalinity. Evaluations of azadirachtin on ectoparasites in animals have been scarce. The purpose of this work was to describe the effects of normal and potentiated azadirachtin on Ctenocephalides felis in the dog or cat. Groups of kennelled greyhounds and domestic cats infested with C. felis were sprayed once with azadirachtin containing neem seed extract with or without diethyltoluamide (Deet) and / or citronella. Methanolic extracts with 200, 1000 or 2400 ppm azadirachtin reduced fleas in a dose-dependent manner. Compared with fleas counted on treated dogs just before treatment and untreated infested dogs, 1000-2400 ppm azadirachtin reduced fleas 93-53% for 19 days. However, combined with 500 ppm Deet and 33% w/v citronella, only 500 ppm azadirachtin reduced fleas 95-62% for 20 days. On cats inoculated with 50 fleas 2 days before treatment, the combination reduced fleas and eggs 100% to day 6 and 83-51% from day 7 and 80% to day 14 and 48-52% to days 21-28. Deet, with or without neem seed extract or citronella, and citronella, with or without neem, did not reduce fleas significantly. The results show that azadirachtin reduced fleas in a dose-dependent manner in flea-contaminated environments. In cats, the combination killed most fleas within 24 h, providing effective flea control for 7 days. The results suggest that Deet with citronella potentiated the effect of azadirachtin on C. felis.

SOURCE: Vet. Parasitol 1998 Jan 31; 74(2-4):289-97

Neem extract as an antibacterial agent against fish pathogenic bacteria
By: Das BK, Mukherjee SC, Sahu BB, Murjani G. - Aquatic Animal Health Division, Central Institute of Freshwater Aquaculture, Bhubaneswar, India
Aquaneem, an emusified product prepared from the Neem A. indica, kernel was tested against four pathogenic bacteria of fish (i.e. Aeromonas hydrophila, Pseudomonas fluorescens, Escherichia coli and Myxobacteria spp.) to test its efficacy as an antibacterial agent. Growth inhibitory property of the product at 10, 15 and 20 ppm has been noticed and recorded. The percentage reduction of bacterial cell population was noted to be maximum on 9th day at 20 ppm concentration (i.e. 70.14%, 74.15% and 61.75% for A. hydrophila, P. fluorescens and E.coli respectively) with the only exception of myxobacteria which showed maximum reduction percentage (63.90%) on 15th day. Among all the bacteria tested A. hydrophila, P. fluorescens and Myxobacteria spp. exhibited maximum sensitivity to Aquaneem in terms of percentage reduction of bacterial cell population in comparison to E. coli.

SOURCE: Indian J. Exp. Biol. 1999 Nov;37(11):1097-100