Bacterial larvicides

The Committee considered the report of the WHO informal consultation on guideline specifications for bacterial larvicides for public health use, held in Geneva from 28 to 30 April 1999 (7), and reviewed the comments on the report and suggestions received from Member States and industry. The Committee made the following recommendations. 

Industrial firms should be encouraged to develop test methods for accelerated storage stability determination for bacterial larvicides. 

The industry should be encouraged to evaluate the applicability of CIPAC and WHO test methods for quality control of bacterial larvicides. 

WHO and FAO should harmonize their efforts for development of specifications for biopesticides. 

WHO regional collaborating centres should be designated to assist Member States in quality control of bacterial larvicides. 

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The major classes of pesticides in use in the Region are organochlo-rine and organophosphorus compounds, Ccirbamates, pyrethroids and bacterial larvicides. Organophosphorus compounds are the most common, followed by pyrethroids. Insecticides are available in a variety of formulations, including emulsifiable concentrates (EC), wet-table powders (WP), dustable powders (DP), suspension concentrates (SC), oil-in-water emulsions (EW) and capsule suspensions (CS). 

In West Africa, the Onchocerciasis Control Programme is a major user of insecticides. More than 300000 litres of larvicides are applied each year. The use of organophosphorus compounds has progressively reduced, while that of bacterial larvicides has increased and now constitutes more than 50% of the total quantity of larvicides used in the Programme. 

In recent years there has been a rapid increase in the use of insect growth regulators and bacterial larvicides. 

WHO/IPCS should develop guidelines in respect of maximum allowable microbial contaminants for bacterial larvicide products. 

Industry should provide the relevant test methods to determine the identity and content of the active ingredients of bacterial larvicide products. 

Draft guideline specifications for bacterial larvicides for public health use report of the WHO Informal consultation, 28-30 April 1999, WHO, Geneva. Geneva, World Health Organization, 1999 (unpublished document WHO/ CDS/CPC/WHOPES/99.2 available on request from Communicable Disease Control, Prevention and Eradication, World Health Organization, 1211 Geneva 27, Switzerland). 

The azido derivative 683 (CGA 19255) had herbicidal and even better insecticidal activity. 683 prevented the development of the larvae of the house fly (Musca domestica) it was tested successfully as a poultry feed-through lar-vicide " . 684 (CGA 72622 cyromazine, Larvadex ), a metabolite of 683 23,824 proved to be better suitable as a larvicide " . It inhibited growth of a great variety of Diptera insect larvae (e.g. house fly, yellow fever mosquito, face fly, sheep blowfly, fall army worm). Additionally, 684 was used as anthelmintic . 684 is applied as a food additive for domestic or livestock animals or by spraying it on manure surface. Larvicidal properties of formamido " and formamidino derivatives of 684 have been tested. The bacterial degradation of 684 was investigated . ... 

This survey has also demonstrated that compounds isolated from a number of plants of this family possess a broad spectrum of biological activities such as cytotoxic, anti-fungal, anti-bacterial, anti-malarial, anthelmintic, anti-hepatotoxic, anti-oxidative, anti-ulcer, anti-inflammatory and hypothermic, hypolipimenic, hypotensive and spasmolytic activities. Insecticidal, molluscicidal, nematocidal and larvicidal activities are also... 

Selected members of the l,3,4-thiadiazolo[3,2-a]pyrimidine ring system possess larvicidal activity (housefly), protective activity against bacterial leaf-blight disease of the rice plant, and herbicidal activity. ... 

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