Development of novel pesticides in the 21st century

Abstract

General trends and strategies for novel pesticides are summarized. Global pesticide sales and pesticide discovery research are also briefly reviewed. At least 105 chemical pesticides have been launched during the past decade or are under development: 43 fungicides, 34 insecticides/acaricides, 6 nematicides, 21 herbicides, and 1 herbicide safener. Most of them are safe to humans and environmentally friendly. The most developed fungicides are SDHI (succinate dehydrogenase inhibitors), DMI (demethylation inhibitors), QoI (quinone outside inhibitors), and QiI (quinone inside inhibitors). Due to the development of resistance to fungicides with existing modes of action, many fungicides possessing various novel modes of action have been launched or are under development. The trend of insecticide development is changing from organophosphorus, carbamate, and synthetic pyrethroids to nicotinic and diamide insecticides. During the past decade, compounds possessing a variety of novel modes of action have also been launched or are under development. Flupyradifurone and flupyrimin, exhibiting extremely low honeybee toxicity, have been developed and subjected to practical use. Herbicides possessing varied modes of action, such as acetolactate synthase, p-hydroxyphenylpyruvate dioxygenase, protoporphyrinogen oxidase, and very-long-chain fatty acid elongase inhibition, have been developed, but no herbicides possessing a novel mode action have commercialized in nearly 30 years. It is of interest that cyclopyrimorate, which was recently launched, and tetflupyrolimet, which is under development, have novel modes action: homogentisate solanesyltransferase (HST) and dihydroorotate dehydrogenase (DHODH) inhibition, respectively. The development of useful acaricides and nematicides is also progressing. Some natural product origin pesticides are getting attention.

Keywords: acaricide; fungicide; herbicide; insecticide; nematicide; novel pesticides.

Fig. 1. World pesticide company sales.

Fig. 2. Model for electron transport chain in the mitochondria, and action point of SDHI, QoI and QiI.

Fig. 3. (a) Chemical structures of four QoI fungicides. (b) Chemical structures of six QoI fungicides under development by Chinese companies.

Fig. 4. Chemical structures of QiI fungicide.

Fig. 5. Chemical structures of DMI fungicides.

Fig. 6. Chemical structure of the fungicides with novel or unknown mode of action.

Fig. 7. Chemical structure of other fungicides.

Fig. 8. Structure of nicotinic insecticides and honeybee toxicity.

Fig. 9. New nicotinic insecticides for development in China.

Fig. 10. Chemical structures of 11 novel insecticides and their related compounds.

Fig. 11. Chemical structures of acaricides launched or under development after 2007.

Fig. 12. Chemical structure of new nematicides.

Fig. 13. History of herbicide development and mode of action studies.

Fig. 14. Market size forecast in 50 years for the biopesticide and chemical pesticide (Redraw with reference to the original drawing¹¹³⁾).