Mosquitoes larvae

Phosphorus compounds Mulberry moth larva Mosquito larva Image of granary weevil Tropical cockroach intact insects Tropical cockroach insects without intestines... 

Bacillus thuringiensis israelensis mosquito and black fly larvae... 

Malaria affects an estimated 270 million people and causes 2—3 million deaths annually, approximately one million of which occur in children under the age of five. While primarily an affliction of the tropics and subtropics, it has occurred as far north as the Arctic Circle. The disease essentially has been eradicated in most temperate-zone countries, but some 1100 cases of malaria in U.S. citizens returning from abroad were reported to the Centers for Disease Control during 1990. Malaria is seen today in Southeast Asia, Africa, and Central and South America. It is on the increase in Afghanistan, Brazil, China, India, Mexico, the Philippines, Sri Lanka, Thailand, and Vietnam. Escalation of the disease is because of the discontinued use of the insecticide DDT which effectively kills mosquito larvae, but has been found to be toxic to Hvestock and wildlife. Also, chloroquine (6), a reUable dmg for the prophylaxis and treatment of falcipamm malaria, is ineffective in many parts of the world because of the spread of dmg-resistant strains. 

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. 

The edible parts of parsnips (Pastimea sativa L.), which have been consumed for centuries by humans without causing any obvious harm, were found to contain a chemical of insecticidal and strong synergistic nature (1). The insecticidal constituent, present at about 200 p.p.m., was isolated and identified as 5-allyl-l-methoxy-2, 3-methylenedioxybenzene or myristicin. Its toxicity to various insects [vinegar flies, houseflies, Mediterranean fruit flies, mosquito larvae, Mexican bean beetles, and pea aphids] was established and compared with pyrethrum and aldrin (Tables I and II). The knockdown effect, although definite, was not as great as that of pyrethrum. In tests... 

Bioassay with mosquito larvae for the detection of insecticide residues in fresh and processed fruits and vegetables is feasible, subject to the limitation that the untreated natural product is in itself nontoxic to the larvae at the dilutions tested. 

The purpose of this work was to determine the toxicity to mosquito larvae of insecticide spray residues. That certain insecticides are translocated in plants (4, 5) adds impetus to this study. Fresh orchard fruit sprayed or dusted with preparations containing parathion (0,0-diethyl O-p-nitrophenyl thiophosphate), tetraethyl pyrophosphate (TEPP, HEPP), DDD [2,2-bis(p-chlorophenyl)-l,l-dichloroethane], DDT [2,2-bis(p-chlorophenyl)-l,l,l-trichloroethane], chlorinated camphene, and basic lead arsenate were shipped from California to Yonkers, N. Y., by air express for bioassay. 

As mosquito larvae are relatively easy to kill with insecticides, any toxic spray residue is likely to be detected. Two species of mosquito larvae were used, the yellow fever mosquito (Aedes aegypti L.) and the southern house mosquito (Culex quinquefasdatus Say). Tests with the southern house mosquito were made essentially according to the method of Campbell, Sullivan, and Smith (I), except for the kind of food supplied and size of containers used. 

Larvae of the yellow fever mosquito, which are shallow feeders, were reared at room temperature by methods similar to those used in culturing Anopheles mosquito larvae (2, 6). Filter papers containing the eggs (furnished through the courtesy of R. E. Heal, Merck Co., Inc., Rahway, N. J.) were placed in tap water in shallow porcelain pans (12 X 7 inches, and 2 inches deep). The eggs hatched within 24 hours. When the larvae had hatched, powdered dog biscuit was added daily at the rate of 100 mg. per liter of water. 

Larvae 3 days old were used in testing. Tests were conducted in the same manner as with the southern house mosquito. 

In addition to the tests made on peaches and apricots, samples of prunes from trees that had been sprayed with parathion, DDT, DDD, basic lead arsenate, and toxaphene at the rate of from 1 to 2 pounds of these insecticides per 100 gallons of water were tested on larvae of Aedes aegypti. The trees had been sprayed on April 20 and June 16, 1948. The fruit was harvested on or about September 10. Prunes from trees that had been treated with 1 quart of tetraethyl pyrophosphate and 12 pounds of sulfur dust per acre on June 15, and harvested about July 6, were tested on larvae of the above named species. None of the prune samples tested in this study exhibited any significant toxicity to mosquito larvae as compared with the unsprayed check. 

An aqueous solution containing 1 part in 200,000,000 of parathion gave 50% kill to southern house mosquito larvae (Culex quinquefasdaius Say). Parathion solutions did not lose any toxicity on standing for a month at room temperature (Figure 1). At the end of 2 months, however, the solutions lost their toxicity to mosquito larvae. 

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... 

Figure 1. Relation among Log k of Dehydrochlorination Reaction, Median Lethal Dosage to Mosquito Larvae, and Substituent Constant for Trichloroethyl Compounds...

The data used are given in Table I. The elimination rate constants included were determined at 20° C. (5). The toxicity to mosquito larvae, given as median lethal dosages (concentration in parts per million of water required to cause 50% mortality in 48 hours), was estimated from the data of Deonier et al. (9) and is probably reproducible to within 30%. 

Increased algal growth on leaf litter observed months after treatment, attributed to reduction in grazing stress by mosquito larvae (Hagmann and Porteus 1972)... 

Hagmann, L.E. and D.J. Porteous. 1972. Pre-hatch treatments with Dursban IG granular insecticide for control of mosquito larvae. Down to Earth 28 21-24. 

Unknown Fish exposed to radiolabeled diflubenzuron for33 days contained about 6% of the parent diflubenzuron vs. 54% for alga (Oedogonium cardiacum), 82% for snail (Physa sp.), and 94% for larvae of mosquito (Culex pipiens quinquefasciatus) 42... 

Criteria now recommended for protection of various species include the following dietary loadings, in mg/kg FW ration, of <0.05 for human health, <0.05 for livestock, <1 for honey bees, and <5 for poultry seawater concentrations <0.1 pg/L for estuarine crustacean larvae and, for all aquatic life, restricted or prohibited use of diflubenzuron in saltmarsh mosquito breeding areas and on agricultural lands less than 5 km from coastal areas. No criteria are available or proposed for protection of avian and mammalian wildlife against diflubenzuron, probably because of an incomplete toxicological database. 

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