Efficacy Of Chlorpyrifos Research Articles

Influence of the acaricide emulsion pH on the effectiveness of spray products to control the cattle tick: laboratory and field investigations.

The current work evaluated the efficacy of 10 commercial acaricides in different pHs (4.5, 5.5, and 6.5) in laboratory (adult immersion tests (AIT), pH evaluation over time) and field assays (tick counts and efficacy). In the AIT (n=70), higher efficacies were obtained when the acaricide emulsion had a more acidic pH (4.5), mainly for two combinations of pyrethroids + organophosphate (acaricide 3 and acaricide 9). For amidine, a higher pH (6.5) showed a higher efficacy. Over time, there was a trend in the pH of these emulsions increasing. When the efficacy of chlorpyrifos + cypermethrin + piperonyl butoxide (acaricide 3) at different pHs was evaluated over time (0, 6, 12, and 24h) by AIT, the less acidic pH (6.5) showed a strongly variation in the acaricide efficacy range. The mean pH of the water samples from different regions of Brazil was 6.5. In the field, the association of pyrethroid + organophosphates (acaricide 9) with pH of 4.5 and 5.5 were more effective in tick control than the emulsion prepared with this same spray formulation at pH 6.5. The pH of the acaricide emulsions is an important point of attention and is recommended that the veterinary industry start to develop/share information regarding how the pH can affect the acaricide efficacy.

Efficacy of Chlorpyrifos and Bacillus Thuranginsis Israelinsis against Culex Pipiens (L.)

Culex pipiens (L.) (Diptera: Culicidae) is the most important medical insect in many parts of the world. Biological and natural chemicals have many advantages over the traditional ones in case of mosquito control. The efficacy of two insecticides belonging to different groups chlorpyrifos-ethyle (oranophosphate) and Bacillus thuranginsis var israelinsis) (bio-insecticides)were evaluated against the field and laboratory individuals of late 3rd instar larvae of Culex pipiens at different concentrations and three periods of exposure under laboratory conditions. Results obtained showed that the laboratory strain showed higher susceptibility to the tested insecticides than the mosquito populations collected from Abo-Rewash City, Giza Governorate and the mortality percentage was increased gradually with increasing the insecticide concentrations and the mortality percentage showed significant differences between concentrations and control. Also, The activity of acetyl cholinesterase (AChE), the glutathione S- transferase (GST), Total proteins and the activities of both Aspartate aminotransferase AST(GOT) and Alanine aminotransferase ALT(GPT) were determined were determined after 72 hrs of insecticidal exposure.

Efficacy of chlorpyrifos and fipronil in relation to soil depths against subterranean termites

The present studies aimed at finding the best concentration of chlorpyrifos and fipronil following mixing with the same and different soil depths in laboratory and field trials. Barrier efficacy of these insecticides was measured by determining wood weight loss kept as bait on the treated soils in the field experiment and length of galleries in the laboratory experiments. Results showed that termites were able to penetrate galleries treated with both insecticides at variable distances. Length of gallery and repellence was concentration dependent. Five percent concentration of both insecticides at 45 cm was the best treatment in comparison with other combination of concentration and soil depths. Maximum gallery length and repellence was observed after the application of chlorpyrifos in comparison with fipronil. Fipronil applied at different concentrations following mixing with the same and with different soil depths was the best treatment as a standard pre-construction step.

Novel extraction of German cockroach (Dictyoptera: Blattellidae) fecal pellets enhances efficacy of spray formulation insecticides.

Methanol extracts of German cockroach, Blattella germanica (L.), fecal pellets have limited use as pheromone attractants in the urban environment because of their unpleasant color and odor. To eliminate these characteristics, a novel aqueous extract of German cockroach feces was formulated. Fetal material was extracted with methylene chloride and mixed with water. The aqueous phase of the extract was colorless and relatively odorless compared with methanol fecal extracts. Aqueous extract was bioassayed and compared with methanol extracts for aggregation activity. The efficacy of chlorpyrifos and boric acid formulations was tested with and without the addition of fecal extracts. In tests with chlorpyrifos, the addition of the aqueous extract produced significantly greater mortality in young nymphs than either chlorpyrifos alone or chlorpyrifos + methanol extract. There were no differences in mortality between the 2 extract + boric acid treatments during the test period, and both enhanced mortality.

An elm bark beetle bioassay for residual efficacy of chlorpyrifos and cypermethrin used for the control of Dutch elm disease in Manitoba

Abstract The basal 1 m of the elm trunks were treated with 0.48% (active ingredient, Al) Dursban aqueous solution (chlorpyrifos) or 0.1% (Al) Ripcord aqueous solution (cypermethrin) for control of overwintering native elm bark beetle, Hylurgopinus rufipes, the vector of Dutch elm disease, Ophiostoma (Ceratocystis) ulmi, at Beaudry Provincial Park, near Winnipeg, Manitoba, Canada. A simple and effective bioassay method was developed to determine insecticidal persistence against the native elm bark beetle. Beetles reared in naturally infested elm logs were confined to the surface of elm bark circles taken from the treated trees. Bark circles were cut at various times after treatment using a cordless hole saw and stored at ‐ 32°C until the beetles were available. Mortality/morbidity data for the two treatments were suitable for use in the comparison of the action of the two insecticides over a two‐year period.

Effects of Band Width and Timing of Chlorpyrifos Granule Applications on Stem Rot Incidence and Wireworm Damage to Irrigated Peanut

Abstract The objective of this study was to determine if band width and timing affected the insecticidal and fungitoxic activity of chlorpyrifos granules applied to irrigated peanut. At two locations and in 3 yr, chlorpyrifos granules were applied to flowering-stage or pegging-stage peanuts of the cultivar Florunner through a drop-tube or in 23-cm or 46-cm-wide bands centered over the row. At midseason, all chlorpyrifos treatments, except the widest band width applied at pegging significantly reduced the incidence of stem rot, but no differences were found at harvest. Wireworm populations were highly variable among tests but, when numbers were sufficient for evaluation, all chlorpyrifos treatments reduced wireworm populations and numbers of damaged pods. Application method and timing had little effect on the efficacy of chlorpyrifos as an insecticide. Even though all chlorpyrifos treatments reduced-wireworm damage to peanut pods and at least delayed the onset of stem rot, only the drop-tube application at flowering resulted in increased yield at one location. Orthogonal contrasts of flowering-stage applications versus pegging-stage applications indicated that the flowering-stage applications resulted in higher yields and values per hectare.

Chlorpyrifos Effect on Armored Scale (Homoptera: Diaspididae) Populations in San Joaquin Valley Citrus

Portions of three citrus orchards infested with California red scale, Aonidiella aurantii (Maskell), and with yellow scale, A. citrina (Coquillett), were sprayed either with a commercial rate of chlorpyrifos or left unsprayed. The three orchards included a chlorpyrifos-susceptible A. aurantii population, a chlorpyrifos-resistant A. aurantii population, and a chlorpyrifos-resistant A. citrina population. The levels of efficacy of chlorpyrifos in the field trials confirmed the levels of susceptibility of scales in the laboratory bioassays. Susceptible A. aurantii were killed for 60 d after treatment with one application of properly timed chlorpyrifos. Chlorpyrifos-resistant A. aurantii were held at pretreatment levels for 30 d but increased in numbers similar to those of the unsprayed control plots by 60 d after treatment. There was no significant difference in percentage of parasitism between the sprayed and unsprayed treatments. Resistant A. citrina were unaffected by the chlorpyrifos treatment, both in the number of scales per plant structure as well as in the population structure. The percentage of parasitism was significantly greater in the unsprayed compared with the chlorpyrifos treatment in this population.

Control of First Generation Black Turfgrass Ataenius Adults on a Golf Course Fairway, 1992:

Abstract Two study sites were established, using large (>110 m2) plots to determine the efficacy of chlorpyrifos (Dursban 4E) against black turfgrass ataenius adults. In each case, chlorpyrifos was applied twice, at two week intervals. The first site was a golf course fairway in Concord, MA–creeping bentgrass (40%), annual bluegrass (40%), perennial ryegrass (20%), maintained at 1.3 cm. Plots were 11.6 x 10 m, replicated 3 times, applied with hydraulic sprayer at 880 liter/ha. Plots were treated on 6 and 20 May or on 20 May and 3 Jun, and sample 13 Jul. The second site was a golf course fairway in South Hadley, MA–annual bluegrass (50%), creeping bentgrass (25%), Kentucky bluegrass (25%), maintained at 1.3 cm. Plots were 19 X 10m, replicated 3 times, applied with Hahn sprayer at 704 1/ha. Plots were treated on 7 and 21 May or on 21 May and 4 June and sampled 21 July. Both sites were evaluated by collected 10 soil cores (10.6 cm diam., 4 cm deep), at least 3m from the nearest edge, from each plot. Cores were inspected under magnification in the Amherst laboratory.

Residual Efficacy of Chlorpyrifos and Diazinon Formulations for German Cockroaches (Orthoptera: Blattellidae) on Panels Placed in Commercial Food Preparation Areas2

Ceramic and stainless steel panels were treated with chlorpyrifos (Dursban LO or ME) or diazinon (Knox Out 2FM) and aged in a commercial kitchen. Type of surface (ceramic tile or stainless steel) did not significantly affect residual performance of formulations used for control of adult male German cockroaches, Blattella germanica (L.). Microencapsulation stabilized the residues of both chlorpyrifos and diazinon and caused 100% mortality of susceptible German cockroaches for 8 weeks and resistant cockroaches for 4 weeks. The emulsifiable formulation provided only 0–67% mortality after 1–2 weeks.

Residual Efficacy of Chlorpyrifos 4E Applied through a Center-Pivot Irrigation System on European Corn Borer (Lepidoptera: Pyralidae) Larvae

Applications of chlorpyrifos 4E through an overhead center pivot at 1.12 kg (AI)/ha with and without oil (Sunoco UN) in water volumes of approximately 0.83 cm (1984-1985), 2.03 cm (1984), and 4.82 cm (1985) were compared in bioassays using first instar European corn borer, Ostrtnta nubtlalts (Hiibner). Mortality data were obtained from 24 h bioassays done at four 72-h intervals following insecticide application. During both years, neither irrigation rate nor the addition of oil had a significant effect on efficacy or residual activity of chlorpyrifos when averaged over oil versus nonoil treatments and all irrigation rates respectively. Although not statistically significant, applications with 0.83 cm water without oil resulted in highest mortality, and applications with 2.03 cm (1984) and 4.82 cm (1985) of water with oil resulted in the lowest mortality when averaged over all time periods. Quadratic (1984) and linear (1985) responses over time were observed with all four treatments. Average mortality was 33.9 and 19.9% 12 d after application in 1984 and 1985, respectively.

Efficacy of Chlorpyrifos in Soil in ‘Florunner’ Peanut Fields to Lesser Cornstalk Borer (Lepidoptera: Pyralidae)

Survival of lesser cornstalk borer, Elasmopalpus lignosellus (Zeller), larvae in soil from conventionally tilled and planted ‘Florunner’ peanut, Arachis hypogaea L., fields treated with chlorpyrifos in Alabama and Florida was evaluated by testing first instars every 2 wk after application. Treatments were an untreated control and granular chlorpyrifos applied at planting, planting plus pegging, pegging, or flowering. Larval survival in soil from treated plots varied with time of application, location, and year. Application of chlorpyrifos at planting was effective in 1986 and 1987 (42 and 102 d in Alabama; 102 and 72 d in Florida). The fewer days of effectiveness in Alabama in 1986 was probably caused by accelerated chlorpyrifos degradation from hot, dry weather during the growing season. Effectiveness of the application at flowering time was at least as great as effectiveness of the application at pegging. This study indicates that application of chlorpyrifos at flowering or pegging would be more effective for lesser cornstalk borer management than an application at planting, and that these applications would provide adequate control of the lessercornstalk borer during pod-fill.

Fall Armyworm (Lepidoptera: Noctuidae) Infestations in No-Tillage Cropping Systems

Field experiments comparing no-tillage and plow-tillage practices demonstrated that infestations by the fall armyworm, Spodoptera frugiperda (J. E. Smith), ultimately become similar in either cropping system. However, in certain no-tillage situations where high mulch concentrations were present on the soil surface, oviposition and damage were reduced. Significantly fewer egg masses and damage were sampled on corn, Zea mays L., (3-leaf stage) while seedlings remained within no-tillage mulch. Oviposition quickly became similar to that observed in plow-tillage systems when the plants grew above the mulch canopy of no-tillage. The number of egg masses on corn older than 4 leaves was similar in either cropping system, and leaf injury at plant silking was the same. In a comparison of corn, sorghum (Sorghum bicolor [L.] Moench.), and soybeans (Glycine max L.), the latter crop had no damage in either tillage system while corn and sorghum were heavily infested. Efficacy of chlorpyrifos (0.56 kg [AI]/ha) for controlling fall armyworm leaf damage was similar in corn and sorghum in either cropping system.

Chlorpyrifos compost treatment for vine weevil control: growth of ornamental plants compared with an aldrin standard

SummaryA chlorpyrifos compost treatment (100 g a.i. m−3) was compared with a standard aldrin admixture (20 g a.i. m−3) for its effect on the growth of fifteen ornamental plants. No phytotoxic symptoms were noticed over a period of 18 months but plants exposed to chlorpyrifos were generally smaller than those in aldrin-treated compost. The efficacy of chlorpyrifos in the control of vine weevil is discussed and it is concluded that it could only be recommended in the absence of an alternative.

The efficacy of chlorpyrifos impregnated polyethelene film in controlling leafroller

The efficacy of chlorpyrifos impregnated polyethelene film in controlling leafroller

Efficacy of Chlorpyrifos (Coroban) 5 & 10 G Against Two Major Rice Pests in Tamil Nadu

Efficacy of Chlorpyrifos (Coroban) 5 & 10 G Against Two Major Rice Pests in Tamil Nadu

Declining Field Efficacy of Chlorpyrifos Against Chironomid Midges and Laboratory Evaluation of Substitute Larvicides12

Against chironomids, 6 applications of 1% G chlorpyrifos at 0.11–0.28 kg AI/ha during May–Sept. 1977, and one of 10% CR pellets at 1.12 kg AI/ha in Sept. 1977 were made to partial or entire areas of 2 man-made lakes. The effectiveness of chlorpyrifos against Chironomus utahensis (Malloch), C. decorus Johannsen, Procladius freemani Sublette, and P. sublettei Roback, gradually declined; a rate of 0.11 kg Al/ha was highly effective in May, but in Sept., the granules even at 0.28 kg Al/ha as well as the CR pellets did not give an effective midge control. Pre-, and posttreatment laboratory bioassays conducted on field-collected larvae revealed a shift in susceptibility of midge larvae to chlorpyrifos, temephos, malathion, and fenthion. In Sept.–Oct. 1977, C. utahensis showed 4½-fold resistance to chlorpyrifos and 3-fold to temephos, while C. decorus developed 10-fold resistance to chlorpyrifos and >2- to 4-fold to the other 3 OPs. Resistance in Procladius spp. ranged from 7-fold to malathion to several hundred fold to temephos. Two of the 4 new synthetic pyrethroids tested in the laboratory were highly active against these midges.

Metabolism of chlorpyrifos-14-C in the Eastern subterranean termite.

Termites treated topically with chlorpyrifos-C readily absorbed the material and metabolized it to chlorpyrifos oxygen analog. There also was evidence for some dechlorination of chlorpyrifos to 3-dechlorochlorpyrifos. Subsequent metabolism of chlorpyrifos and chlorpyrifos oxygen analog to water-soluble metabolites proceeded slowly. The efficacy of chlorpyrifos as a termitxcide is obviously related to the rapid formation and relatively slow degradation of the toxic chlorpyrifos oxygen analog in the eastern subterranean termite.