Insect control Insecticidal activity

The first commercially available HCH insecticide sometimes misleadingly called benzene hexachloride (BHC) was a mixture of isomers, principally alpha HCH (65-70%), beta HCH (7-10%), and gamma HCH (14-15%). Most of the insecticidal activity was due to the gamma isomer (Figure 5.1), a purified preparation of which (>99% pure) was marketed as lindane. In Western countries, technical HCH was quickly replaced by lindane, but in some other countries (e.g., China) the technical product, which is cheaper and easier to produce, has continued to be used. HCH has been used as a seed dressing, a crop spray, and a dip to control ectoparasites of farm animals. It has also been used to treat timber against wood-boring insects. 

Abstract Metofluthrin (commercial name SumiOne, Eminence ) is a novel pyrethroid insecticide developed by Sumitomo Chemical Co., Ltd. Metofluthrin has extremely high insecticidal activity to various pest insects, especially to mosquitoes. In addition, Metofluthrin has relatively high volatility and low mammalian toxicity. Metofluthrin is therefore suitable for use not only in conventional mosquito control formulations such as coils and liquid vaporizers, but also in a variety of novel devices that do not require heating, such as fan vaporizers and paper and resin emanators. Here we describe the insecticidal activity of Metofluthrin mainly against mosquitoes in various formulations in both laboratory and field trials. 

Pyrethrum refers to the oleoresin extracted from the dried flowers of Tanacetum cinerariaefolium (Asteraceae) and is the source of the pyrethrins, chrysanthemates and pyrethrates. Among the natural pyrethrins, those incorporating the alcohol pyrethrolone, namely pyrethrins 1 and II (Fig. 9), are the most abundant and account for most of the insecticidal activity. The pyrethrins are recommended for control of a wide range of insects and mites on fruit, vegetables, field crops, ornamentals, glasshouse crops and house plants, as well as in public health, stored products, animal houses and on domestic and farm animals. Pyrethrins are sold in a wide variety of formulations, under many different trade names by a large number of different manufacturers. 

However, the acctimulated Information on azadirachtin, while promising, is presently much less than that needed for insecticidal product commercialization (41). The mode of action, structure-activity relationships (SAR s), formulation, and metabolism of azadirachtin are not yet well understood. Furthermore, formulation studies are required prior to product development and commercialization. Consequently, further investigations are needed before the full potential of azadirachtin as an insect control agent or insecticide can be realized. 

Insecticides. The use of iodine-based compounds as insecticides is of minor importance. The active ingredient is Iodofenphos (142). It is formulated to be used in public health and animal husbandry, eg, for cockroach control (see Insect control technology). 

Chemicals have been used to kill or control pests for centuries. The Chinese used arsenic to control insects, the early Romans used common salt to control weeds and sulfur to control insects. In the 1800s pyrethrin (i.e., compounds present in the flowers of the chrysanthemum, Pyrethrum cineraefolium) was found to have insecticidal properties. The roots of certain Derris plant species, (D. elliptica and Lonchocarpus spp.) were used by the Chinese and by South American natives as a fish poison. The active ingredient, rotenone, was isolated in 1895 and used for insect control. Another material... 

In order to evaluate the potential hazards chemical insecticides pose to forest environments, it is essential that adequate and reliable research data be generated on their environmental chemistry (distribution, persistence, movement, metabolic degradation, toxicity, fate, etc.). This paper gives a brief account of some laboratory and field research activities carried out at the Forest Pest Management Institute, Canadian Forestry Service to meet this requirement. Using two chemical insecticides which are extensively used now in forest insect control programs in Canada Viz aminocarb [Trade name, Matacil 4-dimethylamino-m-tolyl N-methylcarbamate] and fenitrothion [0,0-dimethyl 0-(3-methyl-4-nitrophenyl) phosphorothioate], studies conducted at the Institute to elucidate the environmental behavior and fate of forestry insecticides in general will be discussed. 

Precocenes may not provide the new approach to insect control originally expected ("4th generation" insecticides, 9) because they are not active in some major groups of agricultural pests (Lepidoptera) and because their mode of action (cytotoxicity) is not compatible with environmental concerns. Indeed, precocene II has been shown to be hepatotoxic and nephrotoxic in rats (16, 17). However, research on precocenes has led to (at least) two Important conclusions (1) compounds structurally unrelated to the JH biosynthetic pathway can reach critical sites (e.g. epoxidase) within the CA, and (2) such compounds can be catalytically processed (e.g. epoxidlzed) by enzymes of JH biosynthesis. The lax substrate specificity of methyl farnesoate epoxidase in the corpora allata and its catalytic competence might be exploited in the design of irreversible Inhibitors of JH biosynthesis (Figure 1). 

The powerful action of some natural products on the central nervous system may suggest their potential value in insect control. If their mammalian toxicity can be reduced by structural modification they may be useful insecticides. Cartap, a rice insecticide, is a bisthiocarbamate. Its structure was based on that of the natural product, nereistoxln, a neurotoxin isolated from shellfish, and it is likely that an in vivo metabolic conversion of cartap to nereistoxln or related compound is responsible for its activity (11). 

Pyrethrum is not useful in agriculture because of its cost and instability in sunlight. Synthetic pyrethroids, however, have exceptional insecticide activity and photostability and therefore are useful in agriculture, forestry, and public health insect control. 

Maize Insect resistant 5.575 million pounds potentially less insecticide active ingredients in 2001 (14.927 million acres) Calculation of pesticide use in a simulation of high insect pest infestation based on historical data, assuming 100% pest control by insect resistant Bt maize. Rationale for the simulation were the low actual infestation levels in recent years that would have obscured the potential change in insecticide use under insect pressure. 

Research remains to be done on the residual activity and mammalian toxicity of the chloronitroethane insecticides, but our initial studies on design, directed synthesis, and bioassay indicate there is clearly potential for those compounds in insect control. 

In the search for novel insecticides, the so-called GABA system (synapses employing gamma-aminobutyric acid as a putative neurotransmitter) was known for many years as a possible lesion site. Starting from a physiological lesion and working backwards to find insect control products has been rare. It is more common to find and then develop natural products with insecticidal activity or to find active chemicals fortuitously from random screens. 

What are the most likely possibilities for the delivery of BT insecticidal activities in the foreseeable future In this author s opinion the greatest opportunity is in the development of new, genetically-manipulated strains of BT applied to crops, forests, and for dipteran insect control by conventional application methods. Our experience at Ecogen has shown... 

Similar tests have been conducted with a coleopterous-active MCap product (MYX 1806) targeted against the CPB on potatoes, hi these tests, potato foliar protection and yields were compared for MYX 1806 and its naturally occurring counterpart, Bt variety son diego (M-One insecticide) (Figures 4 and 5). The results confirm that when equivalent toxin rates were applied for each product, the persistence conferred by the MCap system resulted in superior CPB control. Additionally, it was demonstrated that the protected toxin of MYX 1806 could be applied at two thirds the toxin rate, and yet still maintain higher levels of insect control than the full rate delivered by M-One. 

---