Mixture Of Malathion Research Articles

Differential suppression of organophosphorus resistance in Culex quinquefasciatus by the synergists IBP, DEF, and TPP

Organophosphorus (OP) resistance in a population of Culex quinquefasciatus from California is associated with elevated levels of an esterase (Est-2). Exposure of OP-resistant larvae to the synergists IBP ( S-benzyl O,O-diisopropyl phosphorothioate), DEF ( S,S,S-tributyl phosphorotrithioate), and TPP (triphenyl phosphate) decreased the esterase activity to α- and β-naphthyl acetate to or below the level found in the unsynergized susceptible strain. The OP-resistant strain was crossed to a homozygous susceptible strain and the F 1 progeny were backcrossed to the susceptible parent. The progeny from this backcross were selected for insecticide resistance. This was repeated for seven generations of backcrosses with insecticide selection at the LC 50 level, so that the genetic background of the resistant (R) strain became essentially equivalent to that of the S. The seventh selected generation was allowed to breed to establish a colony of known R gene frequency that was checked by esterase assays. Selection of this population over three generations with temephos, malathion, or IBP + temephos at the 80% mortality level increased the R gene frequency. But selection with IBP + malathion decreased the R gene frequency at a rate similar to that of the unselected population. Selection of homozygous-resistant individuals with IBP + temephos and IBP + malathion increased the levels of resistance to the selecting agents slightly (2- to 5-fold). This is associated with an increase in tolerance to IBP of 1.7-fold. If the selective disadvantage associated with the R gene under IBP + malathion selection pressure is also manifest in field populations then IBP + malathion mixtures may be of practical value.

A teratology study of carbaryl and malathion mixtures in rat.

Recently, much controversy has developed in relation to the use of pesticides alone and in mixtures. Mixtures are used as a more efficient method of pest control. Carbaryl and malathion are one of many combinations used today. A limited amount of work has been done with these two pesticides in relation to their teratogenic potential. This study examined the teratological parameters of carbaryl and malathion in combination compared to the effect of the individual insecticides. Formulation grade carbaryl (0, 1, 10, and 100 mg/kg), formulation grade malathion (1 and 50 mg/kg), and a formulation grade mixture of carbaryl/malathion (1/1 and 50/50 mg/kg) were administered daily by gavage for 3 mo prior to and throughout gestation. Dams were sacrificed on d 20 of gestation, and the fetuses were examined for external, skeletal, and visceral malformations. Significant decreases in dam weight gain during pregnancy and a slight decrease in the number of implantations and number of live fetuses per dam were observed with the 100-mg/kg carbaryl group and were further reduced in both combination doses. The combination dose groups showed a significant reduction in placenta weight. No increases were seen in skeletal or visceral anomalies for the individual treatment groups; however, an increase in external hemorrhagic spots was observed with malathion at 50 mg/kg and the high-dosage mixture group.

Synergism Studies with Binary Mixtures of Permethrin plus Methyl Parathion, Chlorpyrifos, and Malathion on European Corn Borer Larvae12

Binary mixtures of permethrin with methyl parathion, chlorpyrifos, and malathion, respectively, in ratios of 9:1, 4:1, 2.3:1, and 1.5:1 insecticide: permethrin were tested for synergistic activity against larvae of Ostrinia nubilalis (Hubner). Statistically significant ( P = 0.05) synergistic activity was exhibited by all tested mixtures of methyl parathion + permethrin and chlorpyrifos + permethrin. On the basis of LD50 values, mixtures of methyl parathion + permethrin were ca. 14- to 89-fold more toxic to the larvae than methyl parathion and ca. 5- to 34-fold more toxic than permethrin. Mixtures of chlorpyrifos + permethrin were ca. 25- to 29-fold more toxic than chlorpyrifos and ca. 5-fold more toxic than permethrin. Synergism was not exhibited by the mixtures of malathion + permethrin.

Joint action of six herbicides with malathon against mosquito larvae of Culex pipiens L

Results had proved that the 6 herbicides tested (Benthiocard, Cremart, Drepamon, Oxadiazon, Propamil and Trifluralin) manifest extremely low toxicity to larvae of Egyptian Culex pipiens L. The median lethal concentrations of which far exceeded those being recorded for malathion (0.068 and 0.012 ppm for the field and malathion resistant strains, respectively) as mosquito larvicide. These LC 50-values varied from 7, 16, 62, 23, 42 and 66 ppm (in case of the field strain) and 7.6, 9, 60, 20, 44 and 68 ppm (in case of the malathion resistant strain), respectively. Mixtures of malathion and the tested herbicides produced fitted toxicity lines except in case of Cremart (againts both field and malathion resistant larvae), Drepamon (againts malathion resistant larvae) and Trifluralin (againts field larve). In these latter cases, herbicides at maximum sub-lethal concentrations, when combined with different concentrations of malathion, caused a definite increase in the toxicity of malathion. These compounds were the strongest synergists, producing about 100% increase in toxicity. The degree of synergism demonstrated by the other herbicides does not appear to be correlated with their relative toxicity to the mosquito larvae. However, synergism was dose- and strain-dependent. Continuous treatments with maximum sub-lethal concentrations of the tested herbicides caused latent mortalities as larvae (8–100%) or pupae (0–61%) and inhibited the adult formation by 36–100%. The corresponding records were from 2% to 76%, from 3% to 22% and from 16% to 84%, respectively, when larvae were discontinuously treated with maximum sublethal concentrations. Some of these treatments also caused insignificant prolongation in the duration of both larvae and pupae.

Standard curves for nuvacron, malathion, sevin, DDT and kelthane tested against the mosquito Culex pipiens L. and the microcrustacean Daphnia magna Straus

The fourth instar larvae of Culex pipiens L. and adults of microcrustacean Daphnia magna Straus were reared under standarized conditions and used as bioassay test organisms for the preparation of the standard log concentration-probit (lc-p) regression lines for each of the following pesticides: nuvacron, malathion, sevin, DDT and kelthane. When the above pesticides were tested against the larvae of C. pipiens, the LC 50 values (in ppm) ranged as follows: nuvacron 0.0014–0.0019, malathion 0.0027–0.0043, sevin 0.059–0.095, DDT 0.233–0.525, kelthane 0.17–0.24 and a mixture of malathion, DDT and kelthane (3 : 10 : 5) 0.1805–0.2451, based on 24-h readings. The corresponding LC 50 values (in ppm) for D. magna were 0.00018–0.00032, 0.000074–0.00013, 0.00063–0.00069, 0.0061–0.0064, 0.071–0.090 and 0.022–0.028 for the aforementioned pestcides. D. magna proved to be more sensitive to all tested pesticides than C. pipiens larvae: it succumbed to concentrations ranging from 0.000032 to 0.004 ppm of nuvacron, from 0.000032 to 0.0016 ppm of malathion, from 0.000032 to 0.02 ppm of sevin, from 0.0008 to 0.1 ppm of DDT, from 0.03 to 0.3 ppm of kelthane and from 0.007 to 0.075 ppm of the mixture. C. pipiens larvae were affected by concentrations ranging from 0.0005 to 0.008 ppm of nuvacron, from 0.0005 to 0.04 ppm of malathion, from 0.008 to 1.0 ppm of sevin, from 0.05 to 2.5 ppm of DDT, from 0.06 to 0.5 ppm of kelthane and from 0.07 to 0.75 ppm of the mixture.

Susceptibility of Adult Hippelates pusio to Insecticidal Fogs12

The mortalities of caged, laboratory-reared Hippelates pusio Loew (eye gnats) exposed to thermal fogs of 9 insecticides were determined under field conditions. Naled and propoxur were most toxic. DDT was least toxic. The other insecticides of intermediate toxicity were: fenthion, dichlorvos, Dursban® ( O,O -diethyl O -3,5,6-tri-chloro-2-pyridyl phosphorothioate), Gardona® (2-chloro-1-(2,4,5-trichlorophenyl) vinyl dimethyl phosphate), CIBA C-9491 O -(2,5-dichloro-4-iodophenyl) O,O -dimethyl phosphorothioate), and a mixture of malathion and Lethane 384® (2-(2-butoxyethoxy) ethyl thiocyanate).

Adjuvants Prolonging the Residual Activity of Low-Volume Formulations of Dichlorvos, Mevinphos, and Malathion in the laboratory12

Apolar adjuvauts that were difficult to evaluate in an aqueous formulation were studied in a technical grade insecticide mixture. The combination was sprayed onto plants and tested as extenders of residual toxicity against 4th-instar Mexican bean beetle, Epilachna varivestis Mulsant, and 3rd-instar southern armyworm, Prodenia cridania (Cramer). Slightly less than half the adjuvants tested improved residual toxidty of the toxicants. Technical mevinphos mixtures with Carboset 525 (acrylic resin), Klucel HA (cellulose ether), and Gantrez AN 119 (polyvinyl ether—maleic anhydride resin) against Mexican bean beetle and Plaskon 9407 (polyester resin), Klucel HA, and Plaskon 9405 (polyester resin) against southern armyworm were effective combinations. Technical dichlorvos mixtures with Plaskon P.E. 258 (polyester resin) and Carboset 525 were the most effective combinations evaluated against Mexican bean beetle. The former along with Plaskon 9407 and 9405 were superior combinations against southern armyworm. Technical malathion mixtures with several adjuvants were difficult to evaluate, probably because of the slow loss of toxicant effectiveness.

Chemical Control of the Alfalfa Weevil in Illinois and Indiana. I. Comparison of Registered and Experimental Materials1

Field and laboratory experiments were conducted during 1967 to determine the effectiveness of registered and experimental insecticides and mixtures of various insecticides for controlling Hypera postica (Gyllenhal) on first crop alfalfa in southern Indiana and Illinois. Tests were conducted under what were considered both highly favorable and unfavorable weather conditions for insecticide activity. Of the registered materials tested, best results were obtained with methyl parathion. Control results with a mixture of malathion and methoxychlor also were impressive. Early in the season when weather conditions were most favorable phorate appeared to give more persistent control than did methyl parathion. A laboratory bioassay of field-applied chemical sprays showed that most materials tested resulted in a lower larval mortality at 50 than at 72°F. Methyl parathion, Baygon (o-isopropoxyphenyl methylcarbamate), and Furadan® (2, 3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) did not appear to be affected significantly by temperature; on the other hand, methoxychlor and in some cases Alfatox® (1.6 lb methoxychlor +0.8 lb diazinon per gallon) gave greater larval mortality at 50 than at 72°F.

Biology and control of the dubas bug, Ommatissus binotatus lybicus de Berg. (Homoptera, Tropiduchidae), infesting date palms in Iraq

The dubas bug, Ommatissus binotatus lybicus de Berg, is a serious pest of the date palm (Phoenix dactylifera) in Iraq, where there are two generations a year. Both nymphs and adults, which are described, suck the sap from the date palm. Repeated heavy infestations cause the weakening and death of some of the palms.The eggs are laid on all the green parts of the palm except the fruits, the majority on the leaflets, especially the upper surface. They are distributed evenly on the four aspects of the date palms, but unevenly on the frond rows, the second and fourth oldest rows having the majority of the eggs in the overwintering and summer generations, respectively. Deposition of eggs of the overwintering generation began in the second week of November and hatching started during the first week of April, the nymphal period lasting 47 days and the adults surviving for 15 days. Eggs of the summer generation were deposited from the second week of June, and hatching started in the first week of August, the nymphal period lasting 50 days and the adults surviving for 13 days. There are five nymphal instars.The nymphs excreted droplets of honeydew, and both nymphs and adults prefer the shady parts of the date palm. In order to escape the severe heat of the summer days, the nymphs and adults of the overwintering generation migrated towards the bases of the new fronds. The sex ratio was nearly 1:1, and the mean number of eggs laid per female was 106. The mortality rate for a constant population level was 98·11 per cent.The eggs were parasitised by a small Chalcidoid. The larvae of the lace wing Chrysopa carnea Steph. and the adults of Coccinella septempunctata L., C. undecimpunctata L., and Chilocorus bipustulatus (L.) preyed upon the nymphs and adults.In tests with inseeticidal sprays containing 240 g. active ingredient per 100 gal. applied at the rate of 1½ gal. per palm against adults and nymphs, DDT and malathion were equally effective, but Dipterex was less so. Similar concentrations of mixtures of malathion with heptachlor and DDT with diazinon were also effective.