Control of wireworms with organophosphorus and carbamate insecticides

Carbaryl, chlorfenvinphos, diazinon, disulfoton, parathion, phorate, fenitrothion, thionazin and trichlorphon were tested for their effectiveness in killing wireworms by broadcast treatments. Each insecticide was tested once or more in two field trials cropped with wheat and two cropped with potatoes. Phorate and parathion were very lethal to wireworms at 4 Ib active ingredient per acre (4–48 kg/ha). Thionazin and diazinon were intermediate in effectiveness and the other insecticides ineffective.     

Persistence and degradation of chlorfenvinphos,diazinon, fonofos and phorate in soils and their uptake by carrots

Analytical methods are described for the determination of residues of chlorfenvinphos, diazinon, fonofos and phorate in soils and carrots. The insecticides, applied in June 1969 at 2 kg (a.i.)/ha, persisted longer in peaty loam than in sandy loam. After 7 months, the sandy loam contained 1% of the applied diazinon and 20–30% of the applied chlorfenvinphos, fonofos and phorate, the latter as its sulphone; the corresponding figures for the peaty loam were 10, 40–50, 40–50 and 30–40% respectively. None of the residues showed any substantial change from October to January. Although high initial concentrations (up to 50 ppm) of the residues in carrots were diluted by plant growth, it is shown that concentrations >1 ppm could be present in marketable crops 12–14 weeks after application at recommended rates. Carrots harvested 26 weeks after sowing contained <0.2 ppm of all insecticides. In contrast, during the first 15 weeks of crop growth the weights of residues in the carrots increased and remained approximately proportional to the square root of the carrot mean weight. Rates of uptake declined as carrot growth declined and subsequently the amounts of chlorfenvinphos, diazinon and fonofos residues in the carrots changed very little, while phorate sulphone steadily declined.     

Persistence and degradation of chlorfenvinphos,chlormephos, disulfoton,phorate and pirimiphos-ethyl following spring and late-summer soil application

Granular formulations of chlorfenvinphos, chlormephos, disulfoton, phorate and pirimiphos-ethyl were broadcast at 2 kg a.i./ha and incorporated to 100 mm into a sandy-loam soil either in May or in September 1971. The relative persistence of their residues, including insecticidally active oxidation products, after both application dates was disulfoton > chlorfenvinphos > phorate > pirimiphos-ethyl > chlormephos. When applied in September all the insecticides persisted for longer than when applied in May. Degradation was slower during the winter while the mean soil temperature at 100 mm depth remained below 6 to 7°C. Rising soil temperature in the following spring rapidly increased the rates of degradation of chlorfenvinphos, chlormephos and pirimiphos-ethyl residues but not of disulfoton- and phorate-derived residues, predominantly the parent sulphones, which had been leached deeper. Ten months after the September application, half the total residues derived from disulfoton and phorate were found below the initial incorporation depth, whereas the other insecticides showed relatively little downward movement. It was concluded that late summer/early autumn applications for carrot fly control would leave appreciable residues of some insecticides in the soil at the beginning of the next growing season which may contribute to the terminal residues in crops. These would be minimised if moderately persistent compounds were used or if doses of persistent ones were substantially reduced.     

Granular systemic insecticides for control of green peach aphid (Myzus persicae) and their effect on yield and quality of tobacco grown in riverside lankas

Abstract

Flue‐cured Virginia (f.c.v.) tobacco grown on deltaic islands or lankas in the Godavari river in Andhra Pradesh, India is subject to heavy infestations of green peach aphid, Myzus persicae Sulz. The relative efficacy of granular formulations of the systemic insecticides phorate, disulfoton, carbofuran, aldicarb and terbufos in controlling the aphid, and their effect on the yield and quality of lanka tobacco have been studied. Aldicarb granules at 1 g/plant and disulfoton at 2 g/plant were found to be the most effective in controlling the aphid, and also resulted in higher yields of green leaf, cured leaf and total bright leaf equivalent (an index of visual quality). Terbufos at 2 g/plant also gave good yields, but was slightly less effective in controlling aphid infestations. Carbofuran at 3 g/plant was the least effective. The chemical quality of f.c.v. tobacco was not affected by the application of granular insecticides to the soil.     

Factors affecting the performance of granular insecticides applied to field beans

Factors influencing the performance of various granular formulations of disulfoton and phorate after foliar application to field beans were investigated by bioassay in controlled environment rooms. Frequent rainfall and high temperature increased activity considerably but humidity had little effect. With disulfoton formulation on pumice rather than fuller's earth, and toxicant concentrations of 7.5% rather than 10% increased toxicity, but effects of formulation were small with phorate. The influence of rainfall and formulation were confirmed in a field experiment. There was evidence for an initial fumigant effect, particularly for phorate, in both laboratory and field experiments. The detailed effects of the various factors at different intervals after applying the granules are discussed in relation to the physical properties of the insecticides and granular carriers. It is suggested that the possibilities of controlling performance by influencing release rates from granules are limited for chemicals such as phorate and disulfoton which are appreciably adsorbed by soil.     

Field experiments to investigate long-term effects of repeated applications of MCPA, tri-allate, simazine and linuron: II. Crop performance and residues 1969–78

In four field experiments begun in 1963, each of four herbicides was applied to plots planted wilh the same crop each year. The annual treatments were: MCPA at 17 kg/ha to barley (Hordeum sativa Jess) and wheat (Triticum aestivum L.) at growth stage 15. tri-allate at 17 kg/ha pre-emergcnce to barley and wheat, simazine at l7kg/ha pre-emergence to maize (Zea mays L.) and linuron in two applications of 084 kg/ha pre- and post-emergence to carrots (Daucus carota L.). MCPA did not affect growth or yield of either barley or wheat. In general tri-allate also did not aftect the crops although wheat yield was depressed in 1978, wheat 1000 grain weight was reduced in 1972 and barley germination percentage was increased in 1973. Simazine did not influence the height, yield or appearance of maize. Linuron normally produced no effect on carrot yield, density and size. However, in 2 years when the post-emergence application was late, density but not yield was lower than in control plots. There was no accumulation of residues of any of these compounds in the soil. Rates of loss were similar to those predicted on ihe basis of laboratory experiments. In a fifth experiment these herbicides were applied twice per year (3 times in the case of linuron) at double the rales above on each occasion to bare plots. These applications ceased in 1968 (1969 for MCPA) but residues were monitored until 1972 except in the case of MCPA. Disappearance rates were similar to those in the cropped plots and residues were largely confined to the top 10 cm. The plots treated with MCPA had developed an enhanced ability lo degrade il prior to 1968. This persisted for 5 years after the final application.     

Response of spring cereal crops to soil residues of ethofumesate*

For evaluation of soil residues of ethofumseate [(±)2-ethoxy-2,3-dihydro-3,3-dimethylbenzofuran-5-yl-methylsulphonate], spring barley (Hordeum vulgare L.) and spring wheat (Triticum aestivum L.) were sown in soil planted 11 months previously with sugar-beet (Beta vulgaris L.) and previously treated with band or broad-cast applications of the herbicide at rates of 1.68-4.48 kg/ha. The height of barley and wheat was suppressed only where ethofumesate was applied broadcast and the soil was not ploughed after sugar-beet harvest. Three months after sowing, the 4.48 kg/ha rate suppressed the height of barley 18% and wheat 34%. In another experiment, barley grew normally on soil treated the previous year with pre-planting and post-emergence applications of ethofumesate where ploughing followed sugar-beet harvest. For all treatments, yields of straw and grain were not significantly lower than those of the untreated check plots. The dissipation of ethofumesate 24 weeks after application to sugar-beet was 89–100% when applied on a band compared to 85-95% when applied broadcast.     

The Efficacy and Residual Toxicity of certain Granular Insecticides against Mustard Aphid,Lipaphis erysimi (Kalt)

Abstract

The systemic activity of four granular insecticides (phorate 10%, Temik 10%, diazinon 5% and Sevidol [8% carbaryl + 8% gamma-BHC]) was evaluated for the control of mustard aphid, Lipaphis erysimi (Kalt). The granules were applied in the soil to one month old mustard plants transplanted in pots. 3rd and 4th instar nymphs were used for the trial. Mortality counts were made 24 hours after release. Of the insecticides tested, phorate and Temik at 1 lb a.i./ac proved most effective. Temik had a quick knockdown effect as compared to phorate, as it gave 100% control within 24 hours, while with phorate 100% kill was obtained only after 72 hours. Diazinon at 4 lb a.i./ac gave 83.3% kill after 72 hours. Sevidol proved ineffective as an aphidicide. Residual toxicity of three of the granular insecticides, namely phorate, Temik and diazinon, was tested. Phorate and Temik at 1 lb a.i./ac exhibited the same residual toxicity up to 4 weeks, i.e. 100% and 76% kill obtained at the end of 2 and 4 weeks respectively. Although the toxicity of both pesticides gradually declined there was no significant difference in percentage kill over a period of 5 weeks. After 6 weeks, however, the mortality recorded with Temik was 37.1% and with phorate was 51.1%. The residual toxicity of phorate was further found to last up to 8 weeks, when the mortality obtained was 40%. The residual toxicity of diazinon sharply declined within 2 weeks.     

Effects of phorate placement on carrot fly control,seedling density and terminal residues in the crop

The application of granules containing 10 % phorate at 1.12,2.24 or 4.48 kg a.i./ha in a narrow slit together with carrot seed significantly reduced seedling emergence in both a mineral and peat soil. When the granules were applied at 2.24 or 4.48 kg a.i./ha in a narrow slit 2.5 cm below the seed, seedling emergence was adversely affected only at the higher rate in the mineral soil. Phorate granules applied with the seed in the peat soil gave a significantly lower plant density than when applied below the seed, but subsequent carrot yields were unaffected because much larger roots were produced. All phorate treatments gave effective reduction of carrot fly larval damage to the roots. On the peat soil, there were significant increases in total phorate residues present in mature carrots with increasing rate of phorate granules placed with the seed. Placement of the granules 2.5 cm below the seed resulted in a 50% reduction in total residues of phorate in whole carrots compared with placing the granules with the seed. Residues resulting from 1.12 kg a.i./ha with the seed or 2.24 kg a.i./ha 2.5 cm below the seed were not significantly greater than residues in untreated carrots.     

Phorate sulfoxidation by plant root extracts

Soybean root homogenates were found to oxidize phorate to phorate sulfoxide. Neither PO nor sulfone derivatives of phorate were detected. Fractionation of soybean root homogenate indicates that the enzyme(s) which oxidize phorate to the sulfoxide are largely (72%) in the 25,000g pellet. In vitro studies of the 25,000g pellet indicate a linear reaction rate at 34°C for periods of up to 2 h at the pH optimum of 5.5. Soybean and bean root 25,000g pellets were twice as active on a mg protein basis as those from barley, corn, wheat, sorghum and over ten times more active than tomato.In vitro studies indicate that Counter, disulfoton, fenthion, aldrin, heptachlor, piperonyl butoxide, sulfoxide, atrazine, SKF525A and p-chlorothioanisole when present at a 10:1 ratio with phorate significantly inhibited soybean root phorate sulfoxidation.     

Control of Whitegrub Lachnosterna (Holotrichia) consanguinea Blanch. (Coleoptera: Scarabaeidae)

Abstract

During and after sowing of groundnuts, dust, granule and emulsion formulations of some insecticides were tried against grubs of Lachnosterna (Holotrichia) consanguinea Blanch. attacking the crop. On the basis of percentage mortality of plants due to the grubs, phorate granules at 3 kg/ha were found most effective when applied both during and after sowing. Heptachior and Thiodemeton granules at 5 kg/ha were second in merit. Post-sowing treatments with dusts and emulsions were not very effective.     

Polarography of demeton,disulfoton and phorate

The polarographic response obtained when demeton-S, disulfoton and phorate, in 2% tetraethyl ammonium hydroxide, were investigated using a cathode ray oscilloscope polarograph depended considerably on the interval between making up solutions and measurement. Direct evidence to confirm previous suggestions that this type of behaviour is due to hydrolysis of the original insecticides to polarographically active SH-containing compounds was obtained by measuring the disappearance of the original insecticides from the solutions by gas-liquid chromatography and by investigating the behaviour of the hydrolysis product for demeton-S and disulfoton synthesised by an independent route. Measurements of electrocapillary curves and other lines of evidence indicate that the electrode process involves adsorption/desorption at the mercury drop. The results emphasise that conditions must be carefully standardised if polarography is used for estimating these insecticides.     

Correspondence

Abstract

Twenty-seven different herbicides were tested at the AUB Agricultural Research and Education Center in the Beqa'a, Lebanon, to determine their effects on weeds in wheat, barley, maize, onion and sugar beet. Each herbicide was tested at three different rates as pre-emergence and post-emergence applications. Unweeded and hand-weeded check plots were included. Data on yield, quality and other agronomic characteristics of the crops tested were recorded.

Concentrations of 1,000 and 10,000 ppm of 2, 4–D caused a significant decrease in the height and grain yield of wheat and barley when sprayed at the 3-leaf stage. At the 5-leaf stage, injury to wheat and barley occurred only when sprayed at 10,000 ppm, whereas an increase in the grain yield was obtained at 1,000 ppm of 2, 4–D acid equivalent (1 kg a.i./ha).

Pre-emergence treatments of atrazine and simazine at 2.5 kg a.i./ha caused a significant increase in the forage and grain yields of maize as compared to unweeded check plots. Wheat, oats, vetch and sugar beet were injured when planted after triazine-treated maize, whereas onions and soyabeans were tolerant. Other promising herbicides tested on maize were C 3095 (N–3–trifluoromethylphenyl–N'–methyl–N'–methoxyurea) and BV– 201 (1–(3′, 4′–dichlorophenyl)–3–methylpyrrolidin–2–one) applied as a pre-emergence spray at 1 and 2 kg/ha respectively.

Pre-planting treatment of EPTC and pre-emergence treatment of pebulate at 2 kg/ha gave a slight increase in the yield of roots of sugar beet. BV–201 and BV–207 (1–(3–chloro–4–methylphenyl)–3–methylpyrrolidin–2–one) were phytotoxic to beet.

In onions, nitrofen, BV–201 and BV–207 at 1–2 kg/ha were promising as pre-emergence and post-emergence sprays. DNOC and dinoseb at 1.5 kg/ha and ioxynil at 0.5 kg/ha sprayed post-emergence increased the yield of onions significantly over the check. No significant effects of these herbicides were observed on the bulb index, moisture content and total soluble solids of onions.     

Assessment of Losses of Hybrid Sorghum ‘CSH-1’ to Earhead Caterpillars,and Comparison of Insecticidal Controls

Abstract

In hybrid sorghum ‘CSH-1’ severe infestation of the earhead caterpillars Cydia sp., Ectomyelois sp., Eublemma sp. nr. gayneri Roths., Heliothis armigera Hub., and Euproctis limbata Wlk, was recorded at Jabalpur (Madhya Pradesh) during 1968. The first two were relatively more serious. The loss in grain yield was estimated to be 18.26 per cent, i.e. about 717 kg/ha.

Among different insecticides tested, carbaryl 0.2 per cent spray proved most effective, followed by endosulfan 0.05 per cent spray. Dichlorvos 0.05 per cent gave good initial kill, but showed little persistent effect.     

Chemical Control of Phalaris minor and Avena ludoviciana in Wheat

Abstract

In field experiments conducted at the Punjab Agricultural University, Ludhiana during 1973–74 and 1974–75, pre-emergence application (one day after sowing) of methabenzthiazuron (1.05 kg a.i./ha), metoxuron (1.6 kg a.i./ha) and chlortoluron (0.75 kg a.i./ha) gave effective control of Phalaris minor and Avena ludoviciana in wheat without any phytotoxic effect on the crop. Methabenzthiazuron, metoxuron and chlortoluron gave 1410, 1420 and 1090 kg/ha, respectively, more grain than the unweeded crop and 590, 600 and 270 kg/ha more than the crop hand-weeded twice. Nitrofen (1.25 kg a.i./ha) applied pre-emergence was effective against P. minor only and gave substantial increase in grain yield. Terbutryne, dichlormate and linuron, while effective against P. minor, also had a phytotoxic effect on the crop.     

Yield losses in weed-free wheat and barley due to post-emergence herbicides

The tolerance of weed-free wheat and barley to a range of herbicides (bromoxynil, methabenzthiazuron, MCPA, bromoxynil + MCPA. linuron, prometryne, diuron, 2,4-D ester and 2,4-D amine) when applied at the crop three-leaf stage, was examined over the 5-year period 1968–72. All chemicals lowered grain yields to some extent, but the variation between chemicals was greater for wheat than for barley. In both crops, methabenzthiazuron was the safest chemical causing only small (<2·0%,) yield losses at rates up to 2·25 kg a.i./ha. At this rate of application yield losses of up to 36% were recorded for the substituted urea derivatives. Both crops had a low tolerance to 2,4-D ester and amine. Yield losses from bromoxynil, bromoxynil + MCPA and MCPA were similar, varying from 4 to 8% al 0·5 kg a.i./ha to 9–24% at 2·25 kg a.i./ha. Pertes de rendement dans le blé et l'orge provoquées, en l'absence de mauvaises herbes, par des herbicides de postlevée Pendant une période de 5 années (1968–1972) les auteurs ont examiné la résistance du béet de l'orge. Traités, en l'absence de mauvaises herbes, au stade 3 feuilles, avec une série d'herbicidcs (bromoxynil, méthabenzthiazuron, MCPA, bromoxynil-i-MCPA, linuron, prométrync. ditiron, 2,4-D ester et 2,4-D a mine). Tous ces produits ont diminué les rendements en grains dans des proportions variées, mais la variation entre produits a été plus grande pour le blé que pour l'orge. Pour les deux céréales, le méthabenzlhiazuron a été le produit le moins toxique, provotjuant seulement de faibles penes de rendement inférieurcs à 2,0%, à des doses allant jusquà 2,25 kg/m.a/ha. A cette dose d'application, des pertes de rendement allant jusquà 36% ont élé enregistrées avec des urées substituées. Les deux éréles ont manifesté uoe faible resistance au 2,4-D estr et amine. Les pertes de rendement provoquées par le bromoxynil, le bromoxynil + MCPA, et le MCPA ont été analogues, variant de 4 à 8% pour 0,5 kg/m.a./ha, jusqu’à 9 à 24% pour 2,5 kg/m.a./ha. Ertragsverluste durch Nachaufiatifherbizide in unkrautfreiem Weizen und Gerste In unkrautfreien Weizen- und Gerstebestánden wurde in fünfjáhrigen Versuthcn (1968–72) die Toleranz der beiden Arten gegenüber folgenden Herbiziden untersucht: Bromoxynil, Methabenzthiazuron, MCPA, Bromoxynil + MCPA. Linuron, Prometryn, Diuron, 2,4-D-Eister und 2,4-D-Amin- salz. Die Behandlung erfolgte jeweils im 3-Blattstadium. Alle Verbindungen erniedrigten zu einem gewissen Grad den kornertrag. Beim Weizen waren aber die Unterschiede zwischen den verschiedenen Herbiziden grösser als bei der Gerste. Methabenzthiazuron war bei Aufwandmengen bis zu 2.25 kg A.S./ha in beiden Getreidearten das sicherste Herbizid und verursachte nur geringe Ertragsdepressionen (<2%). Bei dieser Aufwandmenge wurden bei den Harn-stoffherbiziden bis zu 36% Ertragsverlust festgestellt. Gegen 2,4-D-Ester und 2,4-D-Aminsalz waren Weizen und Gerste wenig tolerant. Die Ertragsverluste durch Bromoxynil, Bromoxynil + MCPA und MCPA waren etwa gleich und betrugen 4–8% bei 0.5 kg A.S./ha bis 9–24% bei 2,25 kg A.S./ha.     

Uptake of chlorfenvinphos and phorate from soil by carrots as influenced by mode of application and cultivar

Granular formulations of chlorfenvinphos and phorate were applied to sandyloam soil at 2 kg a.i./ha either broadcast and incorporated to 2.5 cm, broadcast and incorporated at 10 cm or by the bow-wave method along the carrot rows. Depth of incorporation did not influence the rates of residue decline in the soil. Bow-wave applications produced the highest residues in root and foliage and also reduced the rate of oxidation of phorate. 30 weeks after sowing the carrots, all treatments gave the highest residue concentrations in the uppermost 6 cm of carrot root. The peel of carrots grown in the soil treated to a depth of 10 cm contained 88 % and 23 % of the total chlorfenvinphos and phorate residues respectively. Significant differences were found in the residue concentrations in five carrot cultivars treated with chlorfenvinphos and phorate by the bow-wave method at 1.5 kg a.i./ha. The concentrations were inversely correlated with root size so that amounts of insecticide (μg/carrot) were similar in all cultivars. Prolonged growth of cv. Norfolk Giant slightly extended the period of uptake of chlorfenvinphos, but the uptake of phorate was ultimately less than its rate of dissipation. Neither the method of application nor the selection of carrot cultivar extended the period of uptake very greatly but differences which were obtained in residue concentrations in the carrot may become significant in the event of regulatory control of residue levels.     

Effects of Herbicides on Horticultural Characteristics,Yield and Quality of Onions

Abstract

Seven different herbicides were tested in 1967, and two of these chemicals were further evaluated in 1969 for their efficacy in onions grown in Lebanon. Chloroxuron at 6 kg a.i./ha and Sindone at 1.5 kg/ha gave a significant increase in the bulb weight and yield of onions over unweeded plots. Significant reductions in yield were observed from pre-em. applications of chlorbromuron at 3 kg/ha, propachlor at 6 kg/ha, Sindone at 0.5 kg/ha, and prometryne at 1 and 1.5 kg/ha. Good weed control was obtained as a result of pre-em. application of all herbicides tested.

With post-em. application, weed control was not effective. With the exception of prometryne at 1.5 kg/ha which injured the onions and reduced the yield, the post-em. applications of herbicides tested gave no significant effect on onion yield.

None of the treatments, in both pre-em. and post-em. applications, had any significant effect on leaf length, bulb index, bolting and splitting percentages, dry matter content, total soluble solids, or pungency of onions.     

Effects of placement and distribution on the performance of granular formulations of insecticides for carrot fly control

Effects of granule distribution relative to carrot rows are discussed and further results described. Placing insecticides 5 to 10 cm deep 7.5 cm away from the centre line of the carrot row usually, but not always, improved their performance compared with bow-wave applications. Both sides of the row need to be protected. The efficiency of chlorfenvinphos in a sandy loam, and phorate in a peaty-loam, decreased with increasing distance from the row but they were slightly effective even 19 cm away. The optimum depth for side-placing granules at sowing time varied from 5 to 10 cm, and combining side-placement with a bow-wave application did not greatly enhance efficiency. The most effective combination on a peaty-loam was a bow-wave application of 3 kg phorate/ha at sowing time followed 6 to 9 weeks later by a similar amount side-placed 7.5 cm deep 7.5 cm from the row centre. Comparison of the performance of phorate broadcast, applied by the bow-wave method or deep side-placed indicated that efficiency was improved by restricting the granule distribution but that higher concentrations of granules were then needed in the treated zones to be equitoxic with more uniformly broadcast granules. Uptake by the carrot root system is an important factor in the action of insecticides against carrot fly larvae.     

Integrated pest-management approaches in orchard,cereal and potato protection in Poland1

With its total area of 312,683 km² and a population of about 39 million people, the area of agricultural land per person in Poland is about 0.47 ha. The yields of basic crops are rather low and the losses due to pathogens, animal pests and weeds are high. The use of pesticides is about 1.0–1.3 kg a.i. per ha and this gives a good starting point for integrated pest management (IPM) in the production system of various crops. IPM in glasshouse crops reached the level of 500 ha per year. An IPM approach against codling moth (Cydia pomonella) in orchards allowed a reduction by 70% in the number of insecticide treatments. In the case of apple scab (Venturia haequalis), the IPM approach allowed a reduction in the number of fungicide treatments by 30% on an area of 100,000 ha. In respect to small grains, the IPM approach concerns rational use of fungicides and herbicides in winter wheat and barley. In potato protection, the IPM approach mainly concerns Colorado beetle (Leptinotarsa decemlineata), which at present is controlled by chemical insecticides on 77% of the potato area. Special research and demonstration IPM programmes sponsored by USDA/AID in Central and Eastern Europe will be operational during 1992/1995 and will concern orchards (apple, pear), small grains (wheat, barley) and potatoes.