Larvicides

HCOOCHjCHj. Colourless liquid with the odour of peach-kernels b.p. 54 C, Prepared by boiling ethanol and methanoic acid in the presence of a little sulphuric acid the product is diluted with water and the insoluble ester separated and distilled. Used as a fumigant and larvicide for dried fruits, tobacco and foodstuffs. It is also used in the synthesis of aldehydes. 

Methoprene and hydroprene are first-generation juvenoids that iacorporate minor stmctural optimisation of neotenin to increase persistence. Methoprene, 1-isopropyl (E,E)-ll-methoxy-3,7,ll-tnmethyl dodecadi-2,4-enoate (129) (bp 100 C/6.7 Pa, vp 3.5 mPa at 25°C), is soluble ia water to 1.4 mg/L. The rat oral LD q is >34,000 mg/kg. Methoprene has been used as a mosquito larvicide, ia baits for ant control, and as a catde feed-through treatment for horn fly control. Hydroprene, methyl (H,H)-3,7,ll-trimethyl-dodecadi-2,4-enoate (130) (bp 174°C at 2.5 kPa, vp 2.5 mPa at 25°C), is soluble ia water to 0.54 mg/L. The rat oral LD q is >34,000 mg/kg. Hydroprene is especially effective against aphids and cockroaches. 

Granulars are pelleted mixtures of toxicant, usually at 2.5 ndash 10%, and a dust carrier, eg, absorptive clay, bentonite, or diatomaceous earth, and commonly are 250 ndash 590 ]lni in particle size. They are prepared by impregnation of the carrier with a solution or slurry of the toxicant and are used principally for mosquito larviciding and soil appHcations. 

The compound MON-0585 is a nontoxic, biodegradable larvicide that is highly selective against mosquito larvae. Synthesize MON-0585 using either benzene or phenol as a source of the aromatic rings. 

Use pattern Hexythiazox is a thiazolidinone acaricide which has ovicidal, larvicidal and nymphicidal activities against many kinds of phytophagous mites infesting pome fruits, stone fruits, citrus, vegetables and other food crops. On these mites, hexythiazox works by both contact and stomach action... 

The testing techniques used with mosquito larvae, usually the addition of calculated quantities of the larvicide previously dissolved in a water-miscible solvent, are somewhat more comparable. However, the results here are conflicting. The A. qvxjdnmaculatus larvae are killed within 24 hours by either DDT or DFDT at concentrations somewhat... 

Monofluoroacetic acid offers little promise as a mosquito larvicide, but 2-ethylhexyl monofluoroacetate is a very powerful aphicide. The high toxicity of the fluorinated lower aliphatic acids and their esters to vertebrates probably precludes their use as insecticides except under highly controlled conditions. The toxicity of the fluorinated acids to the vertebrates is attributed to their interference with an enzyme system, but the possibility of finding one with a high specificity for insects is not excluded. 

In the course of work on the mechanism of elimination reactions, the author and his co-workers have measured reaction-rate constants for the second-order elimination of hydrogen chloride from six dichloroethyl compounds of type Ar2CHCHCl2 and three monochloroethyl compounds of type Ar2CHCH2Cl (7). Samples of each of these materials were furnished to the Bureau of Entomology and Plant Quarantine for insecticidal testing, and the author is indebted to C. C. Deonier and I. H. Gilbert for permission to use certain of their data in this paper. The rate constants and larvicidal results are given in Table I. 

Individual applications of 0.014-0.019 kg/ha, emulsifiable concentrate, oil diluent, 3 applications at 5-week intervals 0.02 kg/ha, granularformulation, single application 0.025 kg/ha, single application 0.028 kg/ha (0.025 Ibs/acre), single aerial application, mosquito larvicide granules Individual applications of 0.028 kg/ha, 4 applications at 2-week intervals... 

Moore, J.B. and S.G. Breeland. 1967. Field evaluation of two mosquito larvicides, Abate and Dursban against Anopheles quadrimaculatus and associated Culex species. Mosquito News 27 105-111. 

Mulla, M.S., R.L. Norland, W.E. Westlake, B. Dell, and J.S. Amant. 1973. Aquatic midge larvicides their efficacy and residues in water, soil, and fish in a warm water lake. Environ. Entomol. 2 58-65. 

Nelson, J.H. and E.S. Evans, Jr. 1973. Field evaluations of the larvicidal effectiveness. Effects on Non-target Species and Environmental Residues of a Slow-Release Polymer Formulation of Chlorpyrifos. U.S. Army Environ. Hygiene Agen. Rep. No. 44-022-73/75. Aberdeen Proving Ground, Maryland. 15 pp. 

Schaefer, C.H. and E.F. Dupras, Jr. 1969. The effects of water quality, temperature and light on the stability of organophosphorus larvicide used for mosquito control. Proc. Pap. Annu. Conf. Calif. Mosq. Control Assoc. 37 67-75. 

U.S. Fish and Wildlife Service (USFWS). 1968. Field Appraisal of Tests to Control Salt Marsh Mosquito with Dursban Applied as a Larvicide And Adulticide in Florida. U.S. Fish Wildl. Serv. Spec. Rep., Pesticide Field Appraisal Program, Atlanta, Georgia. Mimeo. 25 pp. 

Action Insecticide, larvicide, ovicide insect growth regulator acting by interference with deposition of insect chitin... 

Ali, A. and M.S. Mulla. 1978a. Effects of chironomid larvicides and diflubenzuron on nontarget invertebrates in residential-recreational lakes. Environ. Entomol. 7 21-27. 

Webb, D.P and K.B. Wildey. 1986. Evaluation of the larvicide diflubenzuron for the control of a multiinsecticide resistant strain of housefly (Musca domestica) on a UK pig farm. Inter. Pest Control 28 64-66. 

Mulla, M.S., H. A. Darwazeh, and M.S. Dhillon. 1980. New pyrethroids as mosquito larvicides and their effects on nontarget organisms. Mosquito News 40 6-12. 

The development of pyrethroids over the last century can be divided into two categories (1) ingredients of household insecticides for use in and around the home, emphasizing safety, and (2) photostable ingredients for outdoor use as agricultural chemicals and for larvicides of sanitary pests. Chemically stable pyrethroids, which were initially developed for outdoor use, are sometimes applied indoors. In such cases, it is absolutely essential to resolve problems, including persistent residues of such compounds indoors, and environmental issues. 

N-Nitroso-N-cyclohexylhydroxylamine is a synergistic agent for insecticides [94] it increases the insecticidal activity ofchlordane. Certain N-alkylphenylnitrosamines [95] and alkyl N-alkyl-N-nitrosocarbamates [96] are insecticides and fungicides, and may also be used for the impregnation of fabrics, etc. They have larvicidal action against Drosophila melanogaster and can also kill all moth larvae and weevils. 

B. G. H., Smith, M. A. Use of 3 trif1uormethy1-4-nitrophenol as a selective sea lamprey larvicide. Great Lakes Fish. 

Schnick, R. A. A review of literature on TFM (3-trifluor-methyl-4-nitrophenol) as a lamprey larvicide. U.S. Fish Wildl. Serv., Invest. Fish Control (1972), 44, 31 pp. 

Methoprene has been fully registered since 1975 for commercial usage as a mosquito larvicide and for control of horn flies via feed-through application to cattle. In addition, methoprene is registered in Japan for administration to silkworms to enhance silk production. As the only IGR currently (July, 1978) registered, it follows that the environmental fate of methoprene has been investigated in detail. 

In summary, photodecomposition of methoprene is facile and leads to a multiplicity of products. The lower photostability in sunlight of methoprene compared to epifenonane has been mentioned previously. Because of its photochemical lability and its ready microbial degradation (see below), methoprene is microencapsulated for aquatic use as a mosquito larvicide. 

Rojas R, Bustamante B, Ventosilla P, Femmidez I, Caviedes L, Gilman RM, Lock O, Hammond GB. (2006) Larvicidal and antimycobacterial and antifungal compounds from the bark of the Peruvian plant Swartzia polyphylla DC. Chem Pharm Bull 54 278-279. 

Carbosulfan, CGA-73,102, and ONCOL are derivatives of carbofuran (2,3-dihydr0-2,2-dimethylbenzofuran-7-yl methylcarbamate) which have broad spectrum activity similar to that of carbofuran but are substantially less toxic to mammals. CGA-73,102 is particularly effective as a soil insecticide by both contact and systemic action (9). Thiodicarb (10) and U-56,299 (11) are highly effective lepidopterous larvicides but are less toxic to plants and mammals than me thorny 1. U-56,299, with a rat acute... 

Figure 1. Relationship between the mosquito larvicidal toxicity (log LC50) of the thiocarbamate derivatives of carbofuran, propoxur and m-isopropylphenyl methylcarbamate (MIP) and logarithm of the octanol/water partition coefficient (log P).

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