Mosquito Control Agent Research Articles

Mosquito control agents derived from petroleum hydrocarbons. IV. Further larval abnormalities produced by FLIT MLO.

The further development of 3rd and 4th stage larvae was delayed or stopped by low dosages of the petroleum hydrocarbon, FLIT® MLO. On the average, the larval period of the southern house mosquito, Culex pipiens quinquefasciatus Say ( =C. fatigans Wiedmann), and the yellow-fever mosquito, Aedes aegypti (L.), was extended for 5 and 12 days, respectively, following corresponding application rates of 0.75 and 2.5 gal/acre. Although many of the larvae survived from 2 to 9 weeks, depending up the species, the final mortality in the treated C. p. quinquefasciatus and A. aegypti was 97 and 95%, respectively. The treated larvae were lighter in body color and the uric acid crystals were more dispersed than in the controls. Extracts of these II-day old “stunted larvae” generally exhibited a reduced amino acid content Degenerative changes in the tracheal trunks of these larvae were noted beginning 10 days after contact with the hydrocarbon.

Predation byNotonecta undulata(Heteroptera: Notonectidae) on Larvae of the Yellow-Fever Mosquito

In various laboratory tests, individual 2nd, 3rd, 4th, and 5th instars of Notonecta undulata Say consumed more Aedes aegypti (L.) larvae than either 1st instars or adults. Fourth and 5th instars consumed the greatest number of larvae. Although all mosquito larval instars were attacked, 2nd instars were killed most often. The mean number of larvae killed per hour increased with increasing prey density. Water temperature had no significant effect on predation rate. Starved adult N. undulata required about 3 hr of active feeding (equivalent to about 30 fourth instars of the mosquito larvae) before they became satiated. Adult backswimmers consistently selected mosquito larvae and pupae over 6 other aquatic prey types. The backswimmer's predatory behavior, elucidated by video recordings and microscope observations, suggests it is well suited to capturing mosquito larvae and pupae. Its ability to kill all aquatic stages of mosquitoes at some time in its life history suggests that N. undulata is well adapted as a predator of A. aegypti and that it warrants further consideration as a mosquito-control agent.

Some Factors Affecting Parasitism by Mermithid Nematodes In Southern House Mosquito1 Larvae2

Various factors affecting the use of a nematode Romanomermis sp., as a biological control agent of mosquitoes were studied. Almost 100% parasitism was obtained when the numbers of parasites in the infective stage to the number of Culex pipiens quinquefasciatus Say exceeded a ratio of 3: 1. The percentage decreased with an increase in the volume of water in which the mosquitoes were exposed but not so rapidly as was expected. Time also proved to be an important factor in determining the extent of parasitism. Second-instar C. p. quinquefasciatus were invaded most readily by the parasite, 3rd-instar larvae were slightly less susceptible than 1st-intar larvae, and limited parasitism occurred in 4th-instar larvae. All parasitized larvae failed to pupate. In addition, salinity may be an important limitation on the habitats of Romanomermis sp.: parasitism was not observed when the culture water had concentrations above 0.04 M NaCl, and a sharp drop was evident at concentrations between 0.015 and 0.030 M NaCI.

Mosquito control agents derived from petroleum hydrocarbons. 3. The effect of FLIT MLO on first and second larval instars.

The petroleum hydrocarbon, FLIT MLO, markedly retarded the development of the 1st and 2nd larval instars of the southern house mosquito, Culex pipiens quinquefasciatus Say (=C. fatigans Wiedmann) , and the yellow-fever mosquito, Aedes aegypti (L.), when applied to the water surface in 11¾, × 7-inch enameled pans at dosage rates of 0.5, 1, 2, and 4 gal per acre. Maximum delay in development and maximum mortality were obtained at the rate of 2 gal per acre, which delayed the onset of pupation as much as 9 days and prolonged larval development for as long as 42 days. Gross and microscopic observations of “stunted” specimens revealed abnormalities in the tracheal system, alimentation, pigmentation and response to external stimuli.

The Relationship of Purple Martins to Mosquito Control

RECENTLY articles and advertisements have appeared in newspapers and publications throughout the United States urging the public to erect bird houses in order to establish colonies of Purple Martins (Progne subis). The publicity proclaims that a martin consumes 2,000 mosquitoes per day, and either states or implies that martins provide effective biological control of mosquitoes. This is somewhat reminiscent of a controversy raised many years ago over the use of bats as mosquito control agents (see Allen, 1939; Storer, 1926). This paper reviews the scientific and popular ornithological literature regarding the diet and feeding behavior of the Purple Martin, in order to ascertain what if any role martins play in the control of mosquito populations.

Mosquito control agents derived from petroleum hydrocarbons. II. Laboratory evaluation of a new petroleum derivative, FLIT MLO.

A new petroleum hydrocarbon, FLIT MLO, has been developed which exhibits properties far superior to those of no. 2 diesel oil as a mosquito control agent. When tested against all aquatic stages and adults of southern house mosquitoes, Culex pipiens quinquefasciatus Say, ( =C. fatigans Wiedmann), yellow-fever mosquitoes, Aedes aegypti (L.), and common malaria mosquitoes, Anopheles quadrimaculatus Say, FLIT MLO proved effective at dosage rates as low as 1 gal/acre with increasing activity at higher temperatures. FLIT MLO attacked all stages of the mosquito life cycle by delaying egg hatch, interfering with development of early larval instars, and producing high mortalities of 4thinstar larval and pupae. It also produced a high mortality in adults during emergence. Insecticide-resistant strains were found to be equally susceptible to this control agent. Resistance to 3 types of petroleum hydrocarbons (aromatic, paraffinic, and a mixture) has not been induced in C. p. quinquefasciatus after more than 2 years of continuous selection pressure.

Mosquito control agents derived from petroleum hydrocarbons. I. Laboratory effectiveness.

One hundred ten hydrocarbons derived from petroleum were evaluated against the eggs, larvae, and pupae of the southern house mosquito, Culex pipiens quinquefasciatus Say, ( =C. fatigans (Wiedemann), and the yellow-fever mosquito, Aedes aegypti (L.), using 6 different test procedures. Of the test materials, 56 ranged from 2 to 8 times as effective as the no. 2 diesel fuel standard against larvae, 25 produced 100% mortality in C. fatigans pupae when applied at the rate of 5 gallons per acre, 20 exhibited a greater residual effect than the standard, and 25 were faster acting than the control. The test materials were generally more effective against the aquatic stages of C. p. quinquefasciatus than those of A. aegypti . The 2 test procedures involving the water surface application of oils to containers of larvae and pupae were found to be the most satisfactory for routine evaluation of the materials.