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1.
《Crop Protection》1988,7(5):336-337
The effectiveness of carbofuran 300 ST and 350 L applied to the soil and as a seed treatment was evaluated with two wheat cultivars ‘Genaro’ and ‘Sonoyta’ in the Valle del Yaqui, Ciudad Obregon, Sonora in Northwestern Mexico. Both the soil and seed treatment significantly (P < 0·05) reduced greenbug, Schizaphis graminum (Rondani) and corn leaf aphid, Rhopalosiphum maidis (Fitch) populations. Infestations of greenbugs and corn leaf aphids were 97·8% and 98·3% less, respectively, with the soil application of carbofuran 350 L in the Genaro wheat plots and 91% less for both aphids in the Sonoyta wheat plots than on the untreated controls. Greenbug and corn leaf aphid infestations in the seed treatment with carbofuran 300 ST on the Genaro wheat plots were 93·4% and 52·5% less, respectively, and in the Sonoyta wheat plots, infestations of greenbugs and corn leaf aphids were 92% and 78·9% less, respectively, than on the untreated controls. The wheat plots where carbofuran 350 L was applied to the soil had yields 18% and 16% greater for the Genaro and Sonoyta cultivars, respectively, than the untreated controls, while those plots where carbofuran 300 ST was applied as a seed treatment had yields 15% and 12% greater for the Genaro and Sonoyta cultivars, respectively, than the untreated controls.  相似文献   

2.
The inhibition of mycelial growth of Rhizoctonia solani in vitro was strongest with pencycuron, followed by tolclofos-methyl, carboxin and thiabendazole. Against cowpea seedling rot in soil infested with R. solani, tolclofos-methyl was most effective, followed by pencycuron, thiabendazole and carboxin. Of nine insecticides tested, only parathion-methyl and quinalphos suppressed mycelial growth of R. solani in vitro, although their activity was much lower than that of the four tested fungicides. The inhibition of mycelial growth by fungicide-insecticide mixtures was antagonistic in only two out of 36 combinations; it was additive in most cases or synergistic, e.g. for most mixtures of pencycuron and insecticides. Quinalphos, applied to the soil, was the only insecticide which reduced cowpea seedling rot in soil infested with R. solani. Soil application of parathion-methyl, phorate, aldicarb or carbofuran and seed treatment with phosphamidon, monocrotophos, endosulfan or dimethoate had little or no effect on seedling rot. Carboxin gave better disease control when applied to the seed already coated with phosphamidon, monocrotophos, endosulfan or dimethoate and when carboxin-treated seeds were sown in soil treated with quinalphos, parathion-methyl, aldicarb or carbofuran. Efficacy of thiabendazole seed treatment was slightly higher in the presence of insecticides, particularly dimethoate. Pencycuron and tolclofos-methyl as seed treatment gave nearly 100% disease control both in the presence and absence of insecticides. The synergistic interactions detected between fungicides and insecticides represent interesting opportunities for the control of R. solani.  相似文献   

3.
Granular aldicarb and carbofuran, systemic carbamate insecticides, were applied at 3 lbs active per acre to compare their control of the meadow nematode (Pratylenchus penetrans). These systemic pesticides were applied either in two bands 2–3 inches from both sides of and at the lower plane of the seed-piece or in one band 4–5 inches wide and 1/2 inch above the seed. Two months after planting, nematode populations were greatly reduced in soil and roots from plots treated with either chemical and with both placement methods. Aldicarb provided effective control longer into the growing season than did carbofuran. When compared with carbofuran, aldicarb-treated potao plants lived longer and produced a greater increase in yield over the untreated plots. Yield increases were greater when either systemic was applied in side bands than when placed over the seed.  相似文献   

4.
Soil-incorporated and foliar-applied insecticides, alone and in combination, were tested in two different tropical sites of Peru. At San Ramon (altitude 800 m) major pests during the wet season were Diabrotica spp. and Myzus persicae. Soil-incorporated insecticides gave protection against Diabrotica but not M. persicae, and yields were significantly lower with these compared with the foliar-applied insecticide, carbofuran. Mean yield was inversely and significantly correlated with mean number of Diabrotica individuals per plant (r=0·989; 0·01 <P<0·05). The foliar-applied insecticide, season, major pests were Phthorimaea operculella, M. persicae and Feltia spp. Mean yield was inversely correlated with mean number of larval mines by P. operculella on foliage (r=0·976;0·02 <P<0·05). The foliar-applied insecticide methomyl, reduced pest damage and increased yields significantly. The major pests during the dry season at Yurimagus (altitude 180m) were Diabrotica spp. Foliar application of carbaryl alone, or in combination with soil-incorporated insecticides, was equally effective in reducing damage and yield loss. An inverse significant correlation (r=0·985; 0·01<P<0·02) for yield vs. damage from Diabrotica spp. was observed.  相似文献   

5.
Subsoil constraints are major limiting factors in crop production in many soils of southern Australia. A field study examined effects of deep incorporation of organic and inorganic amendments in 30–40 cm on soil properties, plant growth and grain yield of wheat (Triticum aestivum var. Ambrook) on a Sodosol with dense sodic subsoil with or without lucerne history in a high rainfall region (long-term average annual rainfall 576 mm) of Victoria. Amendments were applied at a rate of 10–20 t ha−1. Deep ripping alone and deep ripping with gypsum did not significantly affect grain yields. In comparison, application of organic materials doubled biomass production and increased grain yield by 1.7 times. Organic amendment-treated plots produced 60% more grains per area than the untreated control. The crop extracted over 50 mm extra water from below 40 cm soil in organic amendment-treated plots than the untreated control. Nitrogen uptake was almost doubled (403 kg ha−1) in the organic amendment-treated plots than the untreated control (165 kg ha−1). The improved yield with amendments was related to an increase in plant available water in the hostile subsoil, and prolonged greenness of leaves and supply of nitrogen and other nutrients.  相似文献   

6.
Partial soil sterilization with Picfume, Vapam, Vorlex, Terraclor, Telone and combinations of Telone and Picfume have been included in studies for one or more years between 1960 and 1963. All the chemicals tested except Terraclor resulted in yield increases statistically and economically larger than the yields of potatoes produced on the untreated check plots. Partially sterilizing the soil in the fall resulted in large increases in yield of potatoes the following year. The effect of the partial sterilization of the soil lasted for at least two years. The causes for the increases in yield are not known. “Early dying” disease caused byVerticillium alboatrum was known to be present, but increases in yield also resulted from the use of Telone which is predominantly a nematocide. Pathogenic nema were few in number. A combination of Picfume and Telone, economically feasible in Washington, produced large yield increases over a two-year period and did not produce an off flavor in the potatoes when applied in the fall.  相似文献   

7.
A sandy loam soil was treated with 2·5 kg carbofuran/ha on each of five occasions between May and October 1984. In 1985, the field performance of benfuracarb, carbofuran, carbosulfan, chlorfenvinphos and furathiocarb against cabbage root fly (Delia radicum) and carrot fly (Psila rosae) was studied in this soil and in identical but previously untreated soil by applying exponentially increasing doses of granular formulations to radish and carrots at drilling. Chlorfenvinphos reduced numbers of larvae of both pests by >90% in both soils but the performance of all the carbamates was significantly worse in the previously treated soil than in the previously untreated soil. Dazomet, a partial soil sterilant, was applied to part of the experimental area in October 1985 and the performance of aldicarb, carbofuran, carbosulfan, chlorfenvinphos and thiofanox against cabbage root fly was assessed in 1986. The efficiency of aldicarb and chlorfenvinphos was not affected by any of the pre-treatments but that of carbofuran and carbosulfan was reduced in all the pre-treated soils, including the soil treated with dazomet. Carbofuran residues in radish were detectable only in plants grown in previously untreated soil. In laboratory incubations, a dustless base formulation of carbofuran was degraded more quickly in pre-treated than in untreated soils but a granular formulation was degraded more slowly and at a similar rate in both soils.  相似文献   

8.
Field studies were conducted during 1993 and 1994 in the Imperial Valley, California and Maricopa, Arizona to examine relationships between densities of Bemisia tabaci (Gennadius) populations and cotton (Gossypium hirsutum L.) yields, and to estimate economic injury levels (EILs) for pest management application. Populations of B. tabaci were manipulated by applying different numbers of insecticide applications in replicated plots. Resulting insect populations and cotton lint yields were used to develop damage functions and to estimate EILs for all life stages in relation to variable cotton prices, insecticide costs, and pest control efficacy. Economic injury levels declined with increasing cotton prices and increased as the cost of control increased, however, these changes were relatively small, based on typical ranges in price and control costs. In contrast, the efficacy of control provided by insecticide applications had a large influence on EILs, with lower efficacies being associated with higher injury levels. We developed a multiple regression model that accounted for the dynamic changes in the EIL in relation to crop price, control costs, control efficacy, and potential yield. Based on average prices and reasonable control costs and efficacy, EILs ranged from 5.9–15.2 adults/leaf, 6.1–19.8 eggs cm−2, and 1.7–4.7 nymphs cm−2 of leaf area. Additional research is needed to more closely relate the costs of control to the suppression of insect populations, and to define economic thresholds that will enable pest managers to maintain pest populations below EILs.  相似文献   

9.
A low dose of cypermethrin combined with Mamestra brassicae virus was applied weekly against the bollworms Helicoverpa armigera (Hübner) and Diparopsis watersi (Rothschild) in smallholder cotton plots in northern Togo in 1989 and 1990. The timing of treatments was based on action thresholds. One or two additional sprays of Bacillus thuringiensis were applied to control Syllepte derogata F., or dimethoate to control aphids. No significant yield differences were observed between the plots treated with the pyrethroid-virus combination and the control plots, treated with the recommended insecticide schedule. However, the latter had a significantly higher percentage of healthy bolls. The virus applied was not reisolated from insects collected in the field.  相似文献   

10.
A simple statistical procedure has been derived to measure the direct effect of insecticides, particularly any phytotoxic effect, on cereal grain yields. Data from several years' field experiments on the use of insecticides to control larvae of the wheat bulb fly (Delia coarctata Fall.) (Diptera: Anthomyiidae) have been used to determine the ratio of (grain yield ÷ percentrage of undamaged shoots) for plots treated with an insecticide to (grain yield ÷ percentage of undamaged shoots) for untreated plots. A ratio < 1 indicated that the insecticide was phytotoxic; a ratio > 1 suggested that the compound was phytostimulant. The ratios of all the insecticidal seed coatings and soil treatments of granules and sprays which were tested in the field experiments have been measured. The ratios for all insecticides (apart from fonofos microencapsulated seed coating at one site in 1974–1975) were <1. The phytotoxicity of the insecticides was found to vary between years. Insecticidal soil treatments (granules and sprays) seemed to be as phytotoxic as seed coatings. Synthetic pyrethroid seed coatings were slightly less phytotoxic than organophosphorus seed coatings. In field experiments on the control of wheat bulb fly larvae by insecticides, phytotoxicity has usually been estimated by a subjective system of scoring plots visually before larval invasion of plants. This method was compared with the objective method of determining pesticide/untreated (or P/U) ratios. Visual scoring appears to be the more efficient method of determining the most phytotoxic insecticide, whereas the least phytotoxic insecticide is determined more accurately by the method of P/U ratios.  相似文献   

11.
Applying less N on Russet Burbank potatoes (Solanum tuberosum L.) at planting time may reduce the potential loss of N from sandy soil by wind erosion and leaching early in the season. The objective of this study was to evaluate the effect of rate and time of N fertilization on potato production. Potatoes were grown in outdoor pot cultures with N rates of 75,150 and 300 ppm and in field plots with N rates from 112 to 448 kg N/ha applied in single and split applications. The results from pot cultures harvested after one month’s growth showed that yield of tops increased and tuber yield decreased as applied N at planting increased from 75 ppm to 150 or 300 ppm. Field results showed that the yield of potatoes was as high or higher when N applications were split between planting and when plants were 15 to 20 cm tall (early tuberization) as with the same amount of N applied at planting. Generally 112 kg N/ha at planting time was sufficient when additional N was applied after emergence. Split application of N resulted in more second growth on tubers than when all of the N was applied at planting.  相似文献   

12.
《Field Crops Research》2002,79(1):53-65
This research described in this paper examined the impact of varietal mixtures on pest management utilising a model system of partial insecticide applications. In six field experiments conducted in 1995 and 1996 in Igalaland, Kogi State, Nigeria varietal mixtures were simulated through the application of systemic insecticide (carbofuran or furathiocarb) to a pre-determined percentage of a cowpea (Vigna unguiculata) crop. The objective was to examine and compare the pest damage on untreated cowpea plants grown in plots in which varying percentages of the cowpea plants were treated with insecticide. A secondary objective was to determine whether action of the foliage pests influenced flower production. The results showed that the presence of insecticide-treated plants reduced the level of leaf damage by Ootheca mutabilis Sahlberg and the densities of Aphis craccivora Koch populations on untreated plants. The greater the percentage of insecticide-treated plants the greater this reduction on the untreated plants. Meanwhile, the number of flowers found on the untreated plants increased suggesting the foliage pest damage reduced flower production.  相似文献   

13.
In two experiments in established swards of perennial ryegrass and white clover, plots were treated with pesticides to control slugs, leather-jackets, weevil larvae and lucerne flea as selectively as possible. Other plots were treated to control ail of these pests.
Chlorpyrifos application in early summer (to control weevil larvae) and methiocarb pellets (to control slugs) also gave partial control of leather-jackets. Other effects on non-target species were considered to be unimportant, as pest status could not be attributed to the species. A high level of control of lucerne flea by methiocarb pellets, noted previously, was confirmed.
At both sites combined treatment against insect pests and slugs produced large increases in clover content and yield over a 3-year period, in comparison with untreated plots, although clover tended to decline In alt plots. At one site, where the clover content of untreated plots reached 33% at one stage, specialist clover herbivores such as weevils and lucerne flea were more common. Treatments directed against weevils and slugs gave the highest clover yields, and leatherjacket control may also have contributed, particularly when the population reached 0.9 m ha−1 in the final year. At the other site, where the clover content was low (ultimately 01.1–6%), leather-jacket populations reached 2.1 m ha−1 and slug numbers were also relatively high. Control of these species contributed most to the relative increase in clover content and yield.  相似文献   

14.
Management of Childers canegrubs, Antitrogus parvulus Britton, is heavily dependant on organophosphate insecticides. As part of a programme to develop and integrate a wider spectrum of controls, we tested the potential of imidacloprid to control existing infestations of third-instar larvae in sugarcane. Two SC and one WG formulation of imidacloprid (Confidor®) were tested in 11 trials near Bundaberg or Childers in southern Queensland. These defined useful application rates for the formulations, compared the efficacy of formulations, tested surface and subsurface placement, tested different spacings of the coulters behind which the insecticide was applied, and compared the efficacy of early and late applications of the insecticide. Comparisons were made with cadusafos (Rugby® 100 G). Kill of larvae was not as rapid or great as following treatment with cadusafos, but surviving larvae appeared not to be feeding as much. Both SC formulations at rates of at least 3.75 g active ingredient/100 m of row applied into the soil behind coulters placed either side of the stool gave similar gains in cane yield to applications of cadusafos. The WG formulation showed some responses, but was not tested extensively. Application to the soil surface was not as effective as injection into the soil behind coulters. Efficacy seemed to be largely unaffected by the spacing between the coulters. Early applications appear to be more effective than later applications, and lead to larger yield responses. Imidacloprid provides a way of treating infested ratoon crops, does not degrade in high-pH soils, and can be used in rotation with the organophosphate-based cadusafos and chlorpyrifos (suSCon® Blue) to minimise the development of insecticide resistance.  相似文献   

15.
The effect of management of maize residues on the population of insects inimical to the establishment of alfalfa, Medicago sativa L., was examined 1 month after sowing. Alfalfa was sown in early and late April, and late May for 3 consecutive years in Centre County, Pennsylvania, USA. The sowings were made by conservation tillage (direct drilled into maize residue with minimal disturbance of soil) into three different maize residues after (1) silage, (2) silage-plus-winter rye cover and (3) grain. A fourth sowing was by conventional tillage (spring ploughing and harrowing maize residue) after grain. A pesticide, carbofuran (granular formulation) was applied at sowing to half of the plots. Methiocarb bait, a molluscicide, was applied as a split application to the same plots, one-half at sowing and the remainder 2 weeks later. Alfalfa plots in the silage-plus-rye maize residues were colonized with fewer insects than the other residue treatments. Excessive growth of rye in early spring that was not successfully suppressed by herbicide treatment produced vigorous rye plants and fewer alfalfa seedlings. Consequently, silage plus rye had the lowest yield of alfalfa in early April sowings in 2 out of 3 years. Insects known to feed on alfalfa, such as tarnished plant bugs, Lygus lineolaris (Palsot de Beauvois), the plant bug, Plagiognathus politus Uhler, pea aphids, Acyrthosiphon pisum (Harris), and meadow spittlebugs, Philaenus leucophthalmus spumarius (L.), were collected by sweep net 1 month after sowing and less often in the silage-plus-rye treatment. These species were present in greater numbers in the other maize residues that had significantly more alfalfa forage. The insidious flower bug, Orius insidious (Say), and a damsel bug, Nabis americoferus Carayon, were collected in significantly greater numbers in the early April sowings, which corresponded with the peak populations of pea aphid. The potato leafhopper, Empoasca fabae (Harris), was most abundant in plots sowed in late April or late May. Pesticide treatment applied at the time of sowing had very little effect on numbers of insects collected by sweep net 1 month later in 1986 and 1988. However, pesticide treatment significantly increased yield by 280 kg ha?1 in 1987, even though sweep net collections of insects were not reduced by the pesticide treatment. Therefore, the beneficial effect of the pesticide could not be explained on the basis of the insects collected. The highest yields of alfalfa were obtained from the early April sowing into maize residues. This coincided with the time when the majority of alfalfa pests were less abundant than in later sowings; fewer pests were found on the sowings into silage-plus-rye residue. Also, when the rye forage yield was combined with the alfalfa yield, this became the most productive system.  相似文献   

16.
Corn rootworm (Diabrotica spp.) has become the most concern and widespread insect pest of corn (Zea mays L.) production in North America. Two field experiments were conducted to assess the agronomic and yield performance of transgenic rootworm trait, Bacillus thuringiensis (Bt) Cry3Bb, seed-coating treatment, and a soil-applied insecticide under natural corn rootworm infestation. Experiment 1 compared a conventional corn hybrid with and without insecticide (Force 3G) with its near isoline Bt hybrid from 2003 to 2005, on a clay loam soil. Experiment 2 investigated the same treatments as in Experiment 1 plus an additional seed-coated Poncho treatment on a sandy loam in 2004 and 2005. Rootworm population before the crop anthesis, root node injury and root:shoot dry weight ratio during the early grain filling stage, and stalk lodging and grain yield were determined. Our data showed that rootworm population diminished over the 3 years owing to rootworm displacement and adverse weather conditions. At the clay loam site, both Force 3G and the Bt hybrid significantly reduced the larval populations, root injury and lodging score, and increased root:shoot ratio. Over the 3 years, grain yields of the Bt hybrid were 11–66% greater than the untreated non-Bt isoline hybrid; yield of the non-Bt hybrid treated with Force 3G was also significantly greater than the same untreated non-Bt hybrid in 2 of 3 years. Despite less root node injury in the first rows of non-Bt plants adjacent to the Bt plots was observed, yield benefit of this effect remained to be proven. On sandy loam soil, the larval population was very low and there were no differences in root node injury and plant lodging among all the four treatments in either 2004 or 2005. The yield of the Bt hybrid was up to 10% greater than its non-Bt isoline hybrid treated or not with an insecticide in 1 year. Our data showed that Bt rootworm seed technology was effective to control the rootworm larvae and protected grain yield under severe infestation. Furthermore, our data suggest that some of the gain in Bt hybrid yield may be attributed to the genetic transformation as observed in sandy loam soil experiment. In all cases, corn producers should be aware of the pest history, rootworm pressure in relation to economic threshold, soil type and the expected cost-to-benefit ratio before deciding to adopt any protective measures.  相似文献   

17.
Field studies were conducted in northwestern Turkey from 1998–2000 to examine population dynamics of adult strawberry blossom weevils (Anthonomus rubi Herbst), and to establish economic injury levels based on the relationship between densities of overwintered adults and yield losses. Adult weevils were sampled weekly in untreated and insecticide-treated plots using a sweep net. Sweep net catches showed that the abundance of A. rubi adults had two peaks; the first between late-April and early-May, and the second between late-June and mid-July. Linear regression revealed a strong relationship between overwintered and new-generation adult densities. The overwintered-generation adults had generally higher mean population densities than the new-generation. A significant linear decrease was observed in strawberry yields as densities of overwintered-generation adults increased. Percentage yield losses varied between 1.64% and 13.42% among sites. Estimated economic injury levels ranged from 1.00 to 4.00 adults per sweep depending on the management scenario, control cost, control efficacy, and crop value.  相似文献   

18.
Conventional alfalfa ( Medicago sativa L.) establishment methods may create considerable potential for erosion. Conservation tillage practices that result in stand establishment without disturbing the soil greatly would be beneficial in reducing soil losses. Thus, field experiments were conducted to evaluate the success of alfalfa establishment without tillage in a perennial grass sod. Variables included rate of carbofuran (2, 3-dihydro-2, 2-dimethyl-7 benzofuranyi methylcarbamate) insecticide and control of existing vegetation with chemicals. Establishment without tillage was compared with a conventional method of establishment. Carbofuran at 1.1 kg ha−1 applied in the row with the seed, when compared with a control, increased yields during the year of planting but no response was observed in the year after seeding. Yields of alfalfa established without tillage using either glyphosate ( N -(phosphonomethyl)glycine) or paraquat (1,1-dimethyl-4, 4-bipyridinium chloride) for sod suppression were equivalent to or better than yields obtained from conventional sowings except for the 2 April sowing. Paraquat was more effective for tall fescue (Festuca arundinacea Schreb.) suppression when applications were made on 26 April after spring tiller emergence was complete than on 2 April when some of the tillers may have been protected from the spray by basal sheath tissue.
Broadcast application of paraquat resulted in higher alfalfa yields and decreased non-alfalfa components due to more complete sod suppression than application in bands over the row.  相似文献   

19.
Effects of the soil systemic insecticides aldicarb, phorate, and disulfoton on potato growth were measured from 1984–1986 on the cultivars Russet Burbank and Centennial. In all seasons, aldicarb was observed to cause a significant promotion of flowering and in one season also caused increased haulm growth. Phorate caused a reduction in these growth parameters in one season. Temporary effects on early season yields were observed from the aldicarb treatment in one year but final yields were never significantly affected by insecticide use alone. During 1985–1986 additional treatments were investigated involving insecticide combinations with the herbicide metribuzin to determine possible insecticide-herbicide interactions. Phorate-metribuzin combinations caused synergistic metribuzin injury symptoms, decreased haulm growth and yield in 1986. Metribuzin also decreased yields of aldicarb treated potatoes in 1986 and disulfoton treated potatoes in 1985. Disulfoton-metribuzin combinations decreased flowering in 1985. These data suggest that soil systemic insecticides can have direct effects on potato growth, independent of effects on pest suppression, and that they may interact with other crop protection chemicals.  相似文献   

20.
D.E. Groth   《Crop Protection》2008,27(7):1125-1130
The increased number of sheath blight (Rhizoctonia solani)-resistant rice (Oryza sativa) cultivars available will allow producers to use less fungicide and avoid significant reductions in grain and milling yields. Among cultivars currently in cultivation in the southern United States, sheath blight resistance levels range from very susceptible to moderately resistant. A study was conducted to determine the response of cultivars, with different levels of susceptibility, to sheath blight inoculations and fungicide application and to determine the impact of sheath blight disease development on rice yield and quality. Sheath blight epidemics in field plots were initiated by inoculation at the panicle differentiation growth stage in 2006 and 2007. Azoxystrobin at 0.17 kg a.i. ha−1 was applied at mid-boot. Inoculation significantly increased sheath blight severity and incidence and caused yield losses of 8% in moderately resistant cv. Jupiter to 40% in very susceptible cv. Trenasse. Milling yields were affected to a lesser extent. Fungicide treatments reduced sheath blight incidence and severity, regardless of cultivar except in Jupiter. Single azoxystrobin applications were effective in minimizing yield loss due to sheath blight in all cultivars.  相似文献   

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