Locust toxicity

Eor practical purposes, the sapwood of all species may be considered to be susceptible to biodeterioration. The heartwood of some species, however, contains toxic extractives that protect it against biological attack. Among the native species that have decay-resistant or highly decay-resistant heartwood are bald cypress, redwood, cedars, white oak, black locust, and black walnut (60). Douglas-fir, several of the pines, the larches, and honey locust... 

Hopf2 concludes that although insect nerve tissues produce substances that simulate acetylcholine and a cholinesterase which is inhibited by organo-phosphorus insecticides, these substances (in locusts at any rate) are not antagonized by atropine. Furthermore, tubocurarine does not poison insects, although it is active in warm-blooded animals and affects the neuromuscular junctions (see pp. 36, 37). In short, different physiological mechanisms appear to be at work in insects. In particular, it seems that acetylcholine, when injected into a variety of insects, has no marked toxic action. It seems then that, in some... 

As mentioned above, to apply to insects a conclusion drawn directly from tests on mammals may sometimes be misleading.3 For instance, American cockroaches have a remarkably high tolerance for acetylcholine,4 but, on the other hand, a substance showing some of the pharmacological properties of acetylcholine does accumulate in flies and cockroaches poisoned with D.D.T. Similarly, Hopf, working with locusts, was unable to demonstrate any increase in toxicity of eserine or T.E.P.P. resulting from the subsequent injection of acetylcholine. From this, Lord and Potter infer that acetylcholine may not be directly involved in the insecticidal action of organo-phosphorus compounds, either because the enzymes which hydrolyse acetylcholine are not inhibited to any considerable extent in vivo or because the functions performed by acetylcholine in mammals are performed by another substance in insects. 

For the Mexican boll weevil a specially prepared calcium arsenate containing up to 20 per cent, of arsenic pentoxide is effective. This is prepared by heating together white arsenic and precipitated chalk in the presence of excess air at 650° C. The cotton plant is not injured by this preparation.10 In Peru about 30,000 acres of cotton fields are dusted annually from aeroplanes with calcium arsenate. Acid arsenates of calcium appear to be more toxic to boll weevils and to locusts than the basic arsenates. This is probably because the latter must be partially hydrolysed to compounds giving more soluble arsenic before toxic results are produced.11 The extensive application of such sprays to cotton plants is frequently followed by heavy infestations of the cotton aphis. This appears to be due in the first place to the positive photo-tropism of the winged females to white substances such as the arsenate, chalk or flour. Increase of the aphis population is then aided by the destruction by the spray of the hymenopterous parasites of the aphis.12... 

This toxic protein is contained in caster seeds but does not pass into the oil. Similar phytotoxins occur in croton seeds (Crotin) jequirity seeds (Abrin) the bark of the locust tree, Robinia pseudo-acacia (Robin) and in the seeds of some leguminous plants (Phasin). The last is but weakly toxic. Ricin is responsible for the toxic effects on eating castor seeds 5 or 6 of these are fatal to a child, 20 to adults, and 3 or 4 seeds may cause violent gastroenteritis with nausea, headache, persistent vomiting, colic, sometimes bloody diarrhea, thirst, emaciation, and great debility. The symptoms usually do not set in until after several days. More severe intoxications cause small frequent pulse, cold sweat, icterus, and convulsions. Death occurs in 6 to 8 d, from the convulsions or from exhaustion. The fatality rate is about 6%. This low fatality rate is due to the destruction of the poison in the alimentary canal. The treatment would be evacuant and symptomatic. Usually, 3 to 10 d are required to complete recovery. 

Insecticides were developed to kill insect pests that are themselves proven to be hazardous to human health. Pesticides have generally been useful to the human race. Insecticides have forever banished the threat of locust plagues that swept nineteenth century America. Also, they have been a primary reason why American agriculture is dominant in the world, and they allow us to debate what to do with our grain surpluses rather than argue over how to increase agricultural productivity to feed our people. Significant occupational exposures to these compounds continue to exist around the world, and this exposure scenario may result in toxicity when inadequate safety precautions are applied. 

Murphy C, Jepson PC, Croft BA. Database analysis of the toxicity of anti-locust pesticides to non-target, beneficial invertebrates. Crop Protect 13 413-420, 1994. 

A number of studies on the metabolism of 3FG and 4FG in Locusta miaratoria have been undertaken. Both 3FG and 4FG are toxic to locust with LD50 s of 4.8 mg/g and 0.6 mg/g respectively. In vitro studies showed that 3FG is metabolized in the fat body, via the NADP-linked aldose reductase, to 3-deoxy-3-fluoro-D-glucitol (3FGL). This metabolite was detected in the hemolymph of the insect and shown to be both a competitive inhibitor and a substrate for NAD-linked sorbitol dehydrogenase, thereby generating 3-deoxy-3-fluoro-D-fructose (3FF) (541. Subsequently, it was shown by in vivo radio-respirometric analysis of C02 and appropriate chase experiments, that 3FG metabolism irreversibly inhibits glycolysis and not the hexose monophosphate shunt or tricarboxylic acid cycle (55). In addition, the release of fluoride ion and H20 from D-[3- H]-3FG was also observed. Based on the mechanism of aldolase (55) and triosephosphate isomerase... 

Among the hexachlorooctahydronaphthalene type compounds, aldrin [309-00-2] was one of the earliest pesticides. It was first synthesized in the United States in 1948. It was produced by Diels-Alder reaction from acetylene and hexachlorocyclopenta-diene. Aldrin readily converts into dieldrin [60- 57-1] on exposure to sunlight or bac-terias. Both aldrin and dieldrin were widely used from 1950 to 1970 for protecting com and cotton crops. They were also used to protect citrus plants and combat soil pests and locust and in the preservation of timber. Because of their high toxicity and hazard to human health, the production of these pesticides ceased in the United States in 1974. After 1974, the uses of these pesticides were limited to control termites. All uses of these... 

Hordenine (anhaline, eremursine, peyocactine, 4-[2-(dimethylamino)ethyl]-phenol. For formula, data, and occurrence, see j phenylethylamine alkaloids. H. is biosynthesized from phenylalanine or tyrosine via tyramine and N-methyltyramine. H. is a sympathico-mimetic. It has diuretic effects, at higher doses it increases blood pressure, and is generally similar to ephedrine and tyramine. In addition H. is an antifee-dant for locusts. H. is used as a cardiac stimulant of low toxicity and as a disinfectant in cases of dysentery. Lit. Acta Crystallogr., Sect. C 47,1450 (1991) Beilstein EIV 13. 1790 Hager (5.) 5, 708 f. nj. Nat. Prod. 50, 422 (1987) 53,882 (1990) Karrer, No. 2471 see also phenylethylamine alkaloids. 

Robinia pseudoacada, the black locust (Fabaceae), is a common cultivar in the United States and in Europe and is commonly escaped from cultivation. The bark contains several toxic proteins (Kingsbury, 1964). The seeds are also known to contain a distinct lectin (Liener et al, 1986). 

In contrast to the leaf surfaces much more is known about the chemistry of the leaf interior, which is probably considerably more complex. These compounds representing nutrients, toxic allelochemicals and allelochemicals with a host plant sign character, influence feeding behavior (see Scriber, Chapter 7). As can be seen from Table 1.1, contact chemoreceptors for all types of compounds have been identified in a variety of insect species. With the exception of the two beetle larvae and the locust, all of the examples are lepidopteran larvae mainly because the two pairs of sensilla styloconica on the galea (maxilla) of these larvae can be investigated easily (Schoonhoven and Dethier, 1966). The relatively small number of contact chemoreceptors (four sensilla with four neurons) and their importance for food plant discrimination (Hanson and Dethier, 1973) make them ideal for the study of contact chemoreception in relation to host plant selection. 

Nitrogen-containing sugar analogs have recently been described fi-om several Fabaceae species. One of them, 2-5-dihydroxymethyl-3,4-hydroxypyrrolidine (DMDP), was first isolated form leaves and roots of Derris elliptica (10). These sugar mimics were shown to be powerfid glucosidadse inhibitors (11). DMDP acts as an antifeedant for locusts and is toxic for certain caterpillars and beetles. It was isolated in our laboratory fi-om the roots of Derris urucu (Mathias, L. Parente, J. P., unpublished data.)... 

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