Emulsion Spray Research Articles

On the Control of Corn Earworm, Heliothis zea, and Dusky Sap Beetle, Carpophilus lugubris, in Sweet Corn1

In 1959, 1960, and 1961 several candidate insecticides were tested for control of the corn earworm, Heliothis zea (Boddie). and the dusky sap beetle, Carpophilus lugubris Murray. In 1959 two materials, other than the standard DDT-oil emulsion. showed promise as good insecticides for earworm control. These were Sevin® (1-naphthyl N -methylcarbamate) and Thiodan® (6,7.8,9,10,10-hexachloro-1,5.5a, 6, 9,9a-hexhaydro-6, 9-methano-2,4,3-benzodioxathiepin-3-oxide). Sevin and Thiodan also gave significant Slip beetle control. In 1960, these two insecticides again gave a high degree of control. Several compounds that showed promise in 1959 for sap beetle control were added to DDT-oil emulsion to determine the effectiveness of the combination of materials for earworm and sap beetle control. Effectiveness was not increased by the addition of several phosphorus-containing insecticides to the DDT-oil emulsion spray. In 1961 several phosphorus-containing compounds and carbamates were tested and compared with the DDT-oil emulsion standard treatment. Only Sevin was equal in effectiveness to the standard treatment. Guthion® ( O,O -dimethyl S -(4-oxo-1,2,3, benzotriazin-3(4 H )-ylmethyl) phosphorodithioate) gave significant control of earworll but was /lot so effective as the DDT-oil emulsion or Sevin.

The Impact of Herbicide Research on Field Practices in Pineapple Culture

Weed control has been a major problem in Hawaiian pineapple production. Hand-hoeing and mechanical cultivation gave way to activated oil emulsion sprays in the 1940's. The 1950's brought the use of preemergence herbicides especially 3–(p–chlorophenyl)–1,1–dimethylurea (monuron). Each method has brought a shift in species distribution. Today, large-seeded species and vegetatively-propagated species are less well-controlled than in the days of contact weeding with oil emulsion sprays. There is need for selective herbicides which will control the weeds which escape the present program.

Control of a Corn Stem Weevil (Hyperodes humilis), and Fall Armyworm with DDT and Parathion in South Florida1

During the season of 1959–60 at Belle Glade, Florida, DDT and parathion emulsion sprays were tested to determine the number of applications required to control the corn stem weevil ( Hyperodes humilis (Gyllenhal)) and the fall armyworm ( Laphygma frugiperda (J. E. Smith)) on young sweet corn. Populations of these insects were decreased significantly and yields of U. S. Fancy and total marketable ears were increased significantly by six applications of DDT or of parathion when applied on the day of seedling emergence and at 4-day intervals thereafter. An application of DDT at planting time preceding the post-emergence DDT sprays resulted in slightly greater infestations by the stem weevil and significantly lower yields. Postemergence DDT treatments resulted in significantly greater stands than in the untreated cheek in a test in which the corn stem weevil was the major pest.

Field Experiments with Bacillus thuringiensis and Chemical Insecticides for the Control of the European Corn Borer, Ostrinia nubilalis, on Sweet Corn in Southwestern Quebec

In 1959, Bacillus thuringiensis Berliner (25×109 spores per Gram) at 2 and 4 pounds of wettable powder per acre was compared with: DDT, 1½ pounds; Sevin® (1-naphthyl N-methylearbamate), 2 pounds; heptachlor, 1.25 pounds; Dylox® (0,0-dimethyl 2,2,2-trichloro-1-hydroxyethyl phosphonate) 2 pounds; and Kepone® (decachlorooetahydro-1,3,4-metheno-2H-cyclobuta [ed]pentalen-2-one), 1 pound. In 1960, two additional preparations, one (30×109 spores per gram) at 2 pounds per acre, the other (75×109 spores per gram) at 2 and 4 pounds, 2 pounds plus half dosage of DDT, and 2 pounds plus half dosage of Sevin were compared with DDT, Dylox and Kepone at the 1959 dosages, and Sevin at 1.2 pounds per acre for the control of the European corn borer, Ostrinia nubilalis (Hübner) on Sweet corn in southwestern Quebec. Each year, in early, July, two applications were made at a week interval with a commercial sprayer. Per cent infested plants and ears and numbers of borers in the plants and ears were obtained by dissecting at harvest 25 corn plants per replicate per treatment. In 1959, plots treated with DDT or Sevin gave more than 91% marketable ears; heptachlor, 84%; Kepone, Dylox, B. thuringiensis at 2 and 4 pounds, 72% to 77%. In 1960, DDT, Sevin, Dylox, Kepone, Thuricide (3O×109 spores per gram), B. thuringiensis at 4 pounds, and the bacillus plus DDT or Sevin gave more than 9.5% marketable ears; B. thuringiensis at 2 pounds, 88.5%. In 1959 only 58% of the cars in the untreated plots were marketable; in 1960,88%. The percentage of untreated plants damaged in 1959 Was 68; in 1960, 24. B. thuringiensis at 2 and 4 pounds per acre under heavy corn borer infestation was inferior to the standard DDT emulsion sprays and did not give adequate control. The results of this 2-year study indicate that susceptibility of the European corn borer to B. thuringiensis is rather low and inconsistent, and under heavy infestations, a relatively high dosage is required for satisfactory control.

Observations on the biology and control of the cabbage stem weevil, Ceutorhynchus quadridens (Panz.), on trowse mustard (Brassica juncea)

During 1958–60, replicated insecticide trials were carried out in East Anglia in an attempt to assess seed losses on Trowse mustard (Brassica juncea) caused by larval infestations of the cabbage stem weevil, Ceutorhynchus quadridens (Panz.). The overwintered adult weevils invade the young growing crops during April and May, and the eggs are laid in the petioles over a period of weeks, depending both on temperature and crop stage, until about mid-June. Egg-laying began on mustard when the plants had produced six to seven broad leaves, but the actual time at which the first eggs were laid seemed to depend mainly on temperatures during May. In the insecticide trials, infestations averaged up to 26 larvae per plant, and none of the untreated plants entirely escaped attack.High rates of γ BHC (5 or 10 per cent, of the weight of seed) gave some control of stem-weevil larvae when kerosene was used as the sticker for the insecticide; 3 per cent, or 5 per cent, phorate and 5 per cent. Telodrin (1,3,4,5,6,7,8,8-octachloro-3a,4,7,7a-tetrahydro-4,7-methanophthalan) gave no control. The control by seed dressing was unreliable and is considered unsuitable for assessing yield losses caused by stem weevil.A single emulsion spray of dieldrin applied during May when the first adult feeding holes were found in the petioles, gave a good control of stem weevil and prevented egg-laying, and this technique seems promising for future work on damage assessment. It is thought, however, that sprays specifically directed against stem weevil would seldom be justified economically on commercial crops of Trowse mustard, but on April-sown crops the first dieldrin spray against blossom beetle, Meligethes aeneus (F.), may give some protection against stem weevil.The damage-assessment experiments gave no reliable indication of the effects of the stem weevil on yields of seed, in spite of their being sited in localities known to have a high weevil population. It was clear, however, that sowing date greatly influenced yields of seed; plants sown in March outyielded those sown in April or early May.

Prevention of Insect Damage to Decked Pine Sawlogs in Massachusetts with BHC Emulsion Sprays

Prevention of Insect Damage to Decked Pine Sawlogs in Massachusetts with BHC Emulsion Sprays

Discriminative application of insecticide against Glossina morsitans Westw

A dieldrin emulsion spray containing 3 per cent, dieldrin (w/v) was applied once to the putative resting places of Glossina morsitans Westw. throughout a comparatively isolated 17-sq.-mile fly-belt in the Kabiganda Valley in southwestern Uganda between October 1957 and September 1958. Concentration areas of the fly consisted of one or more tall trees with associated understorey and thicket. The lower sides of the branches of an average of 6·75 such trees per acre were treated at a rate of about one-fifth of a pound of dieldrin per acre and at a cost of about £250 per sq. mile.Chemical analysis showed a deposit of approximately 0·8g. dieldrin per sq. metre on the surface sprayed, and although 90 per cent, of this had disappeared from the surface after about four months, it is thought that the application remains effective for this period.A very great reduction in the tsetse population was achieved. Small numbers of flies continued to be caught, but it was thought possible that these were being brought in from neighbouring valleys by buffalo, and, hence, that insecticidal application of this sort, if carried out over a wide enough area, might eradicate a tsetse population.

Corn Earworm Oviposition and the Effect of DDT on the Egg Predator Complex in Corn Silk1

During the growing season of 1959, observations were made on five plantings of sweet corn to determine some of the oviposition habits of the moth and to study the effect predators have on the mortality of eggs of the corn earworm ( Heliothis zea (Boddie)). The plantings were made on May 15, May 25, June 4, June 14 and June 24. Earworm oviposition was relatively light in the first three plantings. In the last two plantings egg deposition increased considerably. This increase in activity is usually observed to occur late in the corn-growing season. Newly emerged silks were most attractive to the moths but even after silks were 10 days old, moths were observed to oviposit on them. The main predators responsible for egg mortality were Orius insidiosus (Say), Coleomegilla maculata (DeGeer) and Chrysopa oculata Say. Geocoris punctipes (Say), Nabis ferus (L.) and syrphid larvae were also observed in the silks but in very limited numbers, The effects of treatment with DDT-oil emulsion sprays on predator populations and egg mortality were also observed. Where spraying reduced the number of predators, mortality of earworm eggs was decreased.

Dieldrin lattices applied by aircraft for controlling hoppers of the red locust, Nomadacris septemfasciata (Serville).

Large-scale operational trials of dieldrin lattices applied by aircraft for controlling hoppers of the red locust, Nomadacris septemfasciata (Serv.), were carried out in the North Eukwa outbreak area in south-western Tanganyika during 1958 and 1959. Single swaths of dieldrin aqueous emulsion spray were applied by aircraft to vegetation at wide intervals and in two directions at 90°, forming a rectilinear lattice distribution of poisoned strips of vegetation over large, hopper-infested areas. Hoppers, especially those in bands, were killed on eating the poisoned vegetation in the strips which they encountered during their migrations. An accurate method of lattice layout by aircraft pilots without assistance from ground marking parties was developed, and the whole operation was used on a large scale for controlling the hopper infestation in North Eukwa in 1959.

Insecticide studies on the maize stalk borer, Busseola fusca (Fuller), in East Africa.

Trials in East Africa (chiefly in Tanganyika) are described to show that the time taken for first-instar larvae of Busseola fusca (Fuller) to reach the more closely packed young leaves in the central axis of the maize plant is about ten days, and that insecticides are effective up to the end of this period. Results show that the best time for control is as near hatching of the eggs as possible, but with more persistent insecticides such as endrin, economic control is possible up to five days later.A method of testing insecticides as residual deposits, by allowing first-instar larvae to walk on them, is given, and it was found that isodrin, DDT, endrin and γ BHC are highly effective as residual films. The MLD's for one minute in contact are 1·8 mg./sq.m. for isodrin, 4–7 mg. for DDT, 8·3 mg. for endrin and about 20 mg. for γ BHC. Derris emulsion has no residual effect after drying and is only effective in the liquid state after contact with larvae for several minutes.In a series of field trials over three years, increases in yield of up to 2·6 times the control yields were shown to be possible, and averaged twice the control yield. Endrin was the most consistently effective insecticide, applied as a 2 per cent, dust and as a 0·03–0·04 per cent, emulsion spray. Two applications of endrin at an interval of two weeks were effective, but, for DDT, three applications of an emulsion containing 0·05 per cent. DDT at nine-day intervals were more effective than two while one may be of little value. An application of 2·5 oz./acre of DDT can be effective for 7–10 days, while 1·5 oz./acre of endrin can be effective for 14 days. In general, however, rates per application should not fall below 3·5 oz. DDT or 2 oz. endrin per acre, overall.The superiority of a 5 per cent. DDT dust over one of 2·5 or 1 per cent, makes it more economical in a high-yielding, heavily attacked area. Diazinon and malathion in emulsion sprays are less persistent than DDT.Trials with 4 per cent, malathion dust and 0·15 per cent, malathion emulsion spray were inconclusive on account of heavy damage by Spodoptera sp.Attempts to increase the persistence of malathion and γ BHC by the addition of chlorinated terphenyl resins were also inconclusive, but DDT in emulsion, with resin, appeared more effective than DDT alone.The economics of successful control measures at the prices obtaining at the time are discussed under the various trials.Chemical estimations of the deposits of insecticides retained on the plants showed that between 1·4 and 3·7 per cent, of the quantity applied per unit area can be recovered in this way.In a discussion of the significance of the results in control, it is suggested that spraying the stems only is half as effective as spraying the whole plant.The conditions and results relating to two aerial spray trials are given.The place of control of Busseola in agricultural practice is described, and some of the present results are quoted to show that yields can be increased by good farming practice as much as by control of Busseola.

Brief History of Aphid Control on Potatoes in South Florida, 1946-591

Results are given from 13 seasons of studies for control of the green peach aphid, Myzus persicae (Sulz.), on potatoes. Control of the aphid was often achieved initially and effectively with an insecticide, only to be reduced within a few years so that it was superseded by another toxicant. DDT emulsion sprays gave satisfactory control for about 5 years. Parathion gave satisfactory aphid control for about 10 years and was effective for control of other insects infesting potato plants. Toxaphene was effective in many seasons. Thiodan® (6,7,8,9,10,10-hexachloro- 1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin 3-oxide) is currently recommended for control of the aphid.

The Susceptibility of the Rice Pentatomid Bug, Scotinophara lurida (Burm.), to Insecticides, and the Insecticidal Control of this Pest in Ceylon

The Pentatomid bug, Scotinophara lurida (Burm.), is a serious pest of the rice crop in certain areas of Ceylon. Five or six generations develop on the two annual rice crops, and that which attains the adult stage at the time of harvest of either crop ‘aestivates’ and does not become sexually mature until later. The generations that become adult earlier in each crop season become sexually mature forthwith, and mate and oviposit.In 1952, laboratory experiments to ascertain the susceptibility of adults of S. lurida to a range of modern organic insecticides, and field experiments on insecticidal control, were initiated. The insecticides tested were DDT, BHC, endrin, dieldrin, malathion, Chlorthion, Guthion, Dipterex, diazinon and parathion.In the laboratory, freshly emerged, sexually mature and aestivating bugs were tested separately by topical application on the abdomen, and it was found that the insecticides could be arranged in the following descending order of toxicity, based on the LD50, against the sexually mature adult:— γ BHC, endrin, dieldrin, parathion, Dipterex, Chlorthion, diazinon, Guthion, malathion, DDT. The adults of the aestivating generations, at least prior to becoming sexually mature, were markedly more resistant to all the insecticides tested than were sexually mature bugs of uninterrupted development, the resistance ranging from two-fold to nineteen-fold that of the latter.There is some indication that tolerance to every insecticide does not necessarily increase with increasing age and sexual maturity of the normal adult bug. Thus, whereas with the organophosphorus insecticides increasing sexual maturity is associated with an increase in tolerance, with DDT and endrin the bugs appear to become more susceptible with increasing sexual maturity, while with γ BHC and dieldrin there is little change.The chlorinated hydrocarbon insecticides DDT, toxaphene, chlordane, aldrin, dieldrin, endrin, isodrin and γ BHC and the organophosphorus insecticides malathion, diazinon, Dipterex, Chlorthion, Guthion and parathion have been tested as emulsion sprays against S. lurida in the field. DDT and toxaphene gave the poorest results with about 85 per cent, control of the pest in 24 hours when applied at and above a concentration of 0·045 per cent, active ingredient. The other insecticides are arranged thus in descending order of efficacy against the pest considering the minimum dosage required to give 100 per cent, or near 100 per cent, control within 24 hours of application of the treatment: —parathion 0·02 per cent.→ endrin 0·03 per cent. = Chlorthion 0·03 per cent.→ Dipterex 0·03–0·04 per cent.=Guthion 0·02 per cent.→ dieldrin 0·06 per cent.= malathion 0·06 per cent.= γ BHC 0·06 per cent. → diazinon 0·07 per cent. Aldrin and isodrin were of about equal effectiveness giving about 90 per cent, control of the pest within 24 hours when applied at a concentration of 0·06 per cent, active ingredient.Of the dusts tested, both γ BHC at 1·3 per cent, and dieldrin at 2·5 per cent, gave 100 per cent, control of the pest in 24 hours when applied under still and dewy conditions obtaining in the morning. Under dry, windy conditions however, γ BHC at 1·3 per cent, and 3 per cent, gave better control of the pest than did dieldrin or aldrin dusts.Parathion, dieldrin, endrin, Metasystox and Ekatin were tested for residual action against S. lurida on the rice crop. Parathion was the most effective residually for a period of two days with dieldrin coming next in order of residual effectiveness.Metasystox and Ekatin were tested for their systemic action against S. lurida on three-week-old and ten-week-old rice plants as foliar sprays and as root treatments. Systemic action of a low order of effectiveness against the pest was demonstrated in all cases but the poor results achieved and the high rates of application involved did not warrant their consideration for practical field use.

Relative Efficacy of Several Materials for Control of Poultry Ectoparasites

Nine recently developed chemicals were compared as potential control agents for poultry ectoparasites. Field tests, upon which the summary of results is based, were preceded by preliminary laboratory tests of toxicity of the materials to baby chicks and to poultry ectoparasites. Atgas persicus (Oken) was effectively controlled by a 1% emulsion of Sevin® (1-naphthyl-N-methyl carbamate) applied as a premise spray in conjunction with a 0.5% emulsion spray applied to the birds at the rate of 1 gallon per 100 birds. Promising but inconclusive results were obtained with Dibrom® (0,0-dimethyl-0-(1,2-dibromo-2,2-dichloroethyl) phosphate) and Korlan® (0,0-dimethyl 0-(2,4,5-trichlorophenyl) phosphorothioate) sprays. A 1% Dylox® (0,0-dimethyl 2,2,2-trichloro-1-hydroxyethylphosphonate) spray applied to premises and birds gave unsatisfactory control of the fowl tick. Menacanthus stramineus (Nitz.) was effectively controlled with the following formulations: Dylox solution, 0.5%, spray, 1 gallon per 100 birds; Korlan emulsion, 0.1%, spray, 1 gallon per 100 birds, in conjunction with nest and litter spray; Sevin emulsion, 0.5% spray, 1 gallon per 100 birds; Sevin dust, 0.5%, 4 ounces per 100 birds. Promising but inconclusive results were obtained with 0.25% Korlan suspension spray. Ornithonyssus sylviarum (C. & F.) was effectively controlled with the following sprays applied at the rate of 1 gallon per 100 birds: Co-Ral® (0-(3-chloro-4-methylumbelliferone)0,0-diethyl phosphorthioate) suspension, 0.1%; Dibrom emulsion, 0.25%; Korlan emulsion, 0.25%; Sevin emulsion, 0.25%; Sevin suspension, 0.5%. A 5% Sevin dust applied by puff duster at the rate of 4 ounces per 100 birds was also effective. Unsatisfactory control followed use of the following formulations: Tedion® (2,4,4',5-tetrachlorodiphenyl sulfone, 80% technical) suspension spray, 0.1%, 1 gallon per 100 birds; 3.6 to 4 ounces per 100 birds of 15%. Delphene® (N,N-diethyl-m-toluamide) dust, 4% Dibrom dust, or 3% Tedion dust; 0.3 ounces of Santocel (a powdery silica aerogel) dust per 100 birds; 1% suspension of Dowco 109 (0-(4-tert butyl-2 chlorophenyl) 0-methyl methyl phosphoramidothioate).

Experiments on the Control of Fall Armyworm1in Sweet Corn

In 1957 an experiment was conducted using granulated DDT for control of fall armyworm, Laphygma frugiperda (J. E. Smith). Treatments consisted of one to five weekly applications which did not give satisfactory control. In 1958 two experiments were Conducted. one with granulated DDT and one with DDT emulsion sprays. More satisfactory control was obtained with granulated DDT in 1958 than in 1957, but control was not reflected in yield or number of marketable ears as opposed to nubbins or ear size. In the experiment using DDT emulsion sprays, DDT remained constant in all treatments, and the volume of water was varied. One quart of DDT emulsifiable conentrate in 100 gallons of water was more effective than 1 quart in 50 or 25 gallons of water.

Field Evaluation of Four Insecticides for the Prevention of Lettuce- Yellows Disease with Known Populations of Viruliferous Six-Spotted Leafhoppers

Artificially reared viruliferous six-spotted leafhoppers, Macrosteles fascifrons (Stal), were caged over small areas of lettuce in the field to test the effectiveness of four insecticides (DDT, demeton, malathion, and parathion) applied as emulsion sprays for lettuce-yellows prevention. This leafhopper is the only known vector for the eastern strain of the virus Chlorogenus callistephi var. vulgaris Holmes, causing lettuce-yellows disease in New York State. Differences were found between sprayed and unsprayed lettuce in the incidence of disease, and in the residual effectiveness of insecticides tested. Differences between insecticides were significant but not readily apparent by mere visual inspection. The use of known populations of viruliferous leafhoppers permitted evaluation of sprays where ordinary small-plot and large-field experiments had failed.

Methoxychlor Residues on Vegetable Crops

Methoxychlor was applied to vegetables in small field plots at Beltsville, Md., at 1¾ pounds per acre in dusts and in wettable powder and emulsion sprays, and also at 3 or 3 pounds per acre in wettable-powder sprays. Residues determined at intervals appeared to justify a waiting period of only 1 day from last application to harvest, for summer and winter squash, cantaloupe, eggplant, pumpkin, peppers, tomatoes, Kohlrabi, turnip roots, and strawberries, at the present tolerance of 14 p.p.m. For okra a 1-day waiting period is needed, which would require a tolerance of 20 p.p.m., and for green onions 3 days, which would require a tolerance of 40 p.p.m.

Residual Effectiveness of Chlorinated Hydrocarbons for Control of the Imported Fire Ant1

Experiments were conducted in Alabama from 1953 to 1958 on control of the imported fire ant, Solenopsis saevissima v. richteri Forel. Chlordane as a dust and in granular formulation, aldrin in emulsion spray and granular formulation, dieldrin in emulsion spray and granular formulation and in fertilizer mixture, and heptachlor in granular formulation and fertilizer mixture were applied in late winter or early spring in a series of experiments to permanent sod lands. Two pounds of heptachlor or dieldrin, or 4 pounds of chlordane per acre, when broadcast as granules, were highly effective for control of the ant and afforded good control for a period of 3 to 5 years. In one experiment, granulated dieldrin was effective for a longer period than a dieldrin emulsion spray. Lower dosages of the insecticides gave good control for 1 year after treatment, but they were ineffective thereafter. When the insecticides were mixed with fertilizer, approximately the same degree of fire ant control was obtained as when the insecticides were used alone. Chlordane mound treatment killed the ants in the treated mounds but did not prevent reinfestation. When broadcast treatments lost their effectiveness, the number of mounds per acre was greater than on the non-treated areas, but the new mounds were smaller in size. Based on 1-year results, airplane application of 5% or 10% heptachlor at a rate of 2 pounds of technical material per acre were equally effective for control of the imported fire ant. Soil type appeared to have no effect on fire ant control.

Further Tests with BHC Emulsion Sprays to Keep Boring Insects Out of Pine Logs in Massachusetts1

Journal Article Further Tests with BHC Emulsion Sprays to Keep Boring Insects Out of Pine Logs in Massachusetts Get access W. B. Becker W. B. Becker University of Massachusets, Amherst Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Economic Entomology, Volume 52, Issue 1, 1 February 1959, Pages 173–174, https://doi.org/10.1093/jee/52.1.173 Published: 01 February 1959 Article history Accepted: 27 October 1958 Published: 01 February 1959

Granulated Insecticides for Control of the European Corn Borer in Southwestern Ontario1

In 1956, sweet corn plots treated with hand applicators three times at weekly intervals with granulated endrin at 0.5 lb. of toxicant per acre or with granulated heptachlor at 1.5 lb. for control of the European corn borer (Pyrausta nubilalis (Hbn.)) yielded over 95% marketable ears. Plots treated with DDT emulsion, granulated DDT, and granulated toxaphene at 1.5 lb. of toxicant per acre yielded 80%, 73%, and 62% marketable ears, respectively. Only 2% of the ears in the untreated check plots were marketable. In 1957, a commercial applicator being used. granulated heptachlor at 1 lb. of toxicant per acre, granulated endrin at 0.3 lb., and granulated Dipterex at 1.5 lb. reduced the number of larvae by over 90%; a DDT emulsion spray at 1.5 lb. and granulated DDT at lb., 87% and 84%, respectively. The percentage of marketable ears for the treatments were: heptachlor, endrin, and Dipterex, over 90%; DDT, over 85%; untreated check, 14%.

汚水貯溜そう並びに防火用水内のアカイエカ幼虫に対する Lindane 乳剤撒布の 1 例(第 11 回大会講演要旨)

汚水貯溜そう並びに防火用水内のアカイエカ幼虫に対する Lindane 乳剤撒布の 1 例(第 11 回大会講演要旨)