Effects of azadirachtin on Ctenocephalides felis in the dog and the cat

Azadirachtin-containing 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 on 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 (Deer) 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 days 7 to 9. On petri dishes, the combination achieved 100% egg mortality up to day 7 and 80% to day 14 and 38-52% to 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. (C) 1998 Elsevier Science B.V.

Concurreny based transition refinement for the verification of distributed algorithms

We suggest a new notion of behaviour preserving transition refinement based on partial order semantics. This notion is called transition refinement. We introduced transition refinement for elementary (low-level) Petri Nets earlier. For modelling and verifying complex distributed algorithms, high-level (Algebraic) Petri nets are usually used. In this paper, we define transition refinement for Algebraic Petri Nets. This notion is more powerful than transition refinement for elementary Petri nets because it corresponds to the simultaneous refinement of several transitions in an elementary Petri net. Transition refinement is particularly suitable for refinement steps that increase the degree of distribution of an algorithm, e.g. when synchronous communication is replaced by asynchronous message passing. We study how to prove that a replacement of a transition is a transition refinement.

A review of Australian Neoseiulus Hughes and Typhlodromips de Leon (Acari : Phytoseiidae : Amblyseiinae)

The Australian Neoseiulus Hughes and Typhlodromips de Leon (Acari: Phytoseiidae: Amblyseiinae) are revised and diagnosed, and three new related genera, Knopkirie, gen. nov., Olpiseius, gen. nov. and Pholaseius, gen. nov. are proposed and diagnosed. In Australia, Neoseiulus contains at least 44 species, 18 of which are newly described here, in six species-groups: the barkeri-group, womersleyi-group, cucumeris-group, cangaro-group, paloratus-group, and the paspalivorus-group. Typhlodromips contains six species, two previously described and four new species. Knopkirie contains four species, three of which are newly described here, in two species-groups: the petri-group and the banksiae-group. Olpiseius contains three species, one of which is newly described, all placed in the noncollyerae-group, and Pholaseius is monotypic, with one newly described species. Diagnoses and keys are provided for all Australian species in each of the above genera, as are keys to the amblyseiine genera currently recognised in Australia.