Natural products in plant protection

Natural products can be used to control pests and diseases in crops. These products include anorganic compounds, but also a variety of plant extracts. In the beginning of this century active microbial extracts were discovered as well. Synthetic crop protection chemicals were developed from about 1940 onwards and sustained progress in modern agriculture. The first generation chemicals have aspecific modes of toxic action and are in many instances deleterious to the environment. The second generation chemicals have specific modes of action and meet modern environmental requirements. A disadvantage of these chemicals is the potency of target organisms to acquire resistance. This condition urged agrochemical industry to develop chemicals with new modes of action. Such chemicals can be developed by using natural bioactive products as leads in synthesis programmes. This paper decribes the progress that was made in the development of natural bioactive compounds in pest and disease control.     

Natural products in plant protection

Natural products can be used to control pests and diseases in crops. These products include anorganic compounds, but also a variety of plant extracts. In the beginning of this century active microbial extracts were discovered as well. Synthetic crop protection chemicals were developed from about 1940 onwards and sustained progress in modern agriculture. The first generation chemicals have aspecific modes of toxic action and are in many instances deleterious to the environment. The second generation chemicals have specific modes of action and meet modern environmental requirements. A disadvantage of these chemicals is the potency of target organisms to acquire resistance. This condition urged agrochemical industry to develop chemicals with new modes of action. Such chemicals can be developed by using natural bioactive products as leads in synthesis programmes.This paper decribes the progress that was made in the development of natural bioactive compounds in pest and disease control.     

中国常见仓贮螨类分类综述

本文对国内常风的６３种仓贮螨类,根据Ｇ．Ｗ．Ｋｒａｎｚ１９７８的的分类系统,排列系统分类地位,作为仓贮害虫研究及植物检疫中螨类鉴定的参考。     

Introduction to the efficacy evaluation of plant protection products

Specific scope

This Standard describes the overall process of efficacy evaluation of plant protection products in the registration procedure.

Specific approval and amendment

First approved in 2003‐09. Revision mainly to reflect zonal assessment approved in 2012‐09.     

Toxicity of cyanogen to insects of stored grain

Range-finding studies on the toxicity of cyanogen to all stages of five species of stored product Coleoptera are reported. The species were Rhyzopertha dominica (F), Sitophilus granarius (L), Sitophilus Oryzae (L), Tribolium castaneum (Herbst), Tribolium confusum Jacquelin du Val and Ephestia cautella (Walker). Exposures for 24 h to cyanogen at 1.3 mg litre(-1) controlled all external stages. Control of internal stages of Sitophilus species was achieved by a 5-day exposure to initial concentrations between 13.7 and 27.4 mg litre(-1), whereas R. dominica was controlled at 13.7 mg litre(-1). Cyanogen showed similar toxicity to all tested external stages and, in this respect, was more similar to methyl bromide than to phosphine. Its toxicity to insects increased with both relative humidity and concentration of carbon dioxide. Cyanogen was toxic to insects whether applied as a gas or in an aqueous solution.     

Grain protectants for the control of malathion-resistant insects in stored sorghum

Duplicate experiments were carried out on bulk sorghum stored in South Queensland and in Central Queensland. Bioassays of treated grain, conducted during 6 months' storage, established that fenitrothion (12 mg kg^?1)+ bioresmethrin (1 mg kg^?1), and pirimiphos-methyl (4 mg kg^?1)+ carbaryl (8 mg kg^?1), controlled typical malathionresistant strains of Sitophilus oryzae (L.), Rhyzopertha dominica (F.), Tribolium castaneum (Herbst), and Ephestia cautella (Walker). Chlorpyrifos-methyl (10 mg kg^?1)+ pyrethrins (1.5 mg kg^?1)+ piperonyl butoxide (12 mg kg^?1), and fenitrothion (12 mg kg^?1)+ (1R)-phenothrin (1 mg kg^?1), also controlled the strains of S. oryzae, T. castaneum and E. cautella, but were only partly effective against R. dominica. Methacrifos (15 mg kg^?1) controlled all the tested species except E. cautella. Chemical assays established that the residues and rates of breakdown of these grain protectants on sorghum conformed to the general pattern for other cereal grains; residues from the above treatments were below the individual Maximum Residue Limits recommended by the Codex Alimentarius Commission.     

Mapping potential exposure to drift of plant protection products*

A proposal for a practical, site‐specific approach for farmers has been developed to fulfil the drift restrictions and directions imposed on a registered plant protection product. The approach is based on exposure potential maps, primarily taking account of regional and local application conditions that reduce non‐target exposure. Firstly, the maps are focused on the spray drift exposure pathway. Using geographically referenced data, we have developed four exposure indicators that allow classification of potential non‐target exposure on the basis of local application conditions. This enables us to manage product application restrictions on a field‐to‐field basis by means of the exposure class to which each field is assigned. This easy‐to‐understand information can be distributed as paper maps or as digital maps to the farmer. The farmer himself no longer needs to assess whether local conditions reduce non‐target exposure. All calculations are carried out using very detailed topographic data which suit scales from 1:10 000 to 1:25 000. Processing and analysis of the GeoData is realized through GIS technology.