Control of the Pine Processionary Caterpillar (Thaumetopoea Wilkinsoni Tams) with Diflubenzuron

During 1973-76 trials were carried out to control the pine processionary caterpillar with Dimilin (25% diflubenzuron WP), and commercial treatments with this compound in the forest were followed up until 1978/79. Total mortality of the 1st-3rd instar larvae was obtained in 8-16-year-old Aleppo pine plots after an aerial spray of Dimilin at the rate of 300 g (75 g a.i.) in 50 liter water/ha; 500 g (125 g a.i.)/ha was required to kill all 3rd and 4th instar larvae. A ground spray with Dimilin at a concentration of 0.003% (0.00075% a.i.) in water of 6-year-old Aleppo pine trees infested by 1st-3rd instar larvae gave similar results. The period Dimilin persisted on the sprayed needles in the forest was up to 27 days, even after 91 mm of rain.     

山西吕梁地区三种林分土壤养分与碳密度关系研究

通过在山西吕梁地区分别在山杨(Populus davidiana Dode)、落叶松(Larix principisrupprechtii)、油松(Pinus tabulaeformis)林内设置样地进行林分结构和土壤调查采样,测定了土壤有机碳密度和养分含量,分析了不同林分对土壤有机碳积累的差异性及其影响因素。结果表明:该研究区三种林地土壤有机碳密度山杨林(57.08kg/m2)>落叶松林(16.54kg/m2)>油松林(6.71kg/m2);油松林、落叶松林土壤有机碳密度随着土层深度递减,山杨林则在10-30cm土层土壤有机碳碳密度最低,土壤表层与深层都具有富集作用。土壤中的TN、TP和有机质的含量与土壤有机碳之间的差异变化规律基本相同,山杨林也表现出表层和深层含量较高的特点,相关分析结果说明三种林分类型土壤养分与土壤有机碳碳密度密切相关。     

Effect of environmental factors on herbicidal activity of diphenamid

Diphenamid (N,N-dimethyl-2,2-diphenylacetamide) in an aqueous solution in plastic bottles was partially detoxified when exposed to sunlight for 1 week. Varying spray volumes from 300 to 1,800 I/ha did not have an appreciable effect on the phytotoxicity of diphenamid, sprayed on a coarse or fine soil surface. The marked dissipation of diphenamid which occurred from the soil surface was attributed to photodecomposition and volatilization. Diphenamid phytotoxicity was greater when the first irrigation after spraying was applied in four increments of 100 m³/ha or two increments of 200 m¹/ha than when it was applied in a single 400 m¹/h watering; the latter caused more leaching of the herbicide. The diphenamid fraction leached out of a 4-cm soil layer increased as the organic matter content in the soil decreased, from 25% in peat (22.3% o.m.) to >88% in sandy loam (0.9% o.m.). The herbicidal activity remaining after leaching was lower in sandy loam and in peat than in soil with medium organic matter content (11.6% and 6.2%). Diphenamid degradation rate in soil at 50% field capacity moisture level, increased when temperature was increased from 10° to 30°C. After 4 months of incubation at 10°C, 40-50% of the original herbicide was detoxified, while at 20° and 30°C the loss exceeded 90%. Within the range of day-temperatures of 10° to 40°C in soil and of 10° to 35°C in nutrient solution, diphenamid phytotoxicity to tomato seedlings increased with temperature.     

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.     

Factors effecting the performance of metoxuron and chlortoluron in controlling blackgrass in winter wheat

Blackgrass (Alopecurus myosuroides Huds.) was controlled by 2 kg/ha of metoxuron in glasshouse trials while winter wheat, cultivar Cappelle Desprez, tolerated 4 kg/ha. Blackgrass was controlled by 1.2 kg/ha of chlortoluron. Winter wheat previously damaged by freezing was injured by 2.5 kg/ha of chlortoluron applied at an early stage. Seedlings not exposed to freezing were not damaged by 2.5 kg/ha applied at the 4- and 5-leaf stage. Breakdown of chlortoluron and metoxuron in the soil was attributed, in part, to microbial action. More than one-third of the chlortoluron applied at 2 kg/ha disappeared in 6 weeks when applied in early spring while one half disappeared in 3 weeks when applied 2 months later. The bioassay, used to determine the amount of chlortoluron or metoxuron in the soil, was found to be adequate for metoxuron in only one of three soils. The bioassay results, for both herbicides, were affected by the addition of calcium carbonate to the soil, by sterilization of the soil, and by leaching. In comparisons of results in two sandy loams and a clay loam, the observed differences could not be altogether accounted for by differences in pH nor by changes in adsorption of metoxuron. When perennial ryegrass was grown in sandy loam, and treated with metoxuron before or after emergence, different watering regimes did not give any difference in weight of top growth.     

Potential Nitrification Rates of Semiarid Cropland Soils from the Central Ebro Valley,Spain

The nitrification capacity of agricultural soils has received little attention in semi arid Mediterranean environments in spite of the importance of the NO3 - in the ecosystem. In this study, a laboratory experiment was carried out to evaluate potential nitrification in six agricultural soils from semiarid Central Ebro Valley (northeastern Spain). Triplicate topsoil samples (0¨15 cm) were collected seasonally over a 2-year period. The nitrification capacity was evaluated by fresh soil incubation at 25°C and field capacity with a NH +- N source. Verhulst s equation was used to express the accumulation of NO3 - 4 - N with time. The potential nitrification rate (K max) was derived from the equation and used to quantitatively characterize the nitrification process. The K max , obtained by fitting a sigmoidal curve, allowed us to distinguish the nitrification capacity of each semiarid agricultural soil. The K max varied between seasons which indicate that time-variable soil properties (such as salinity and climate) influenced the nitriflcation rate even in an incubation experiment. On an annual average, K max for saline or highly gypsiferous soils ranged from 8.5 to 9.4 mg NO3 -N kg -1 d -1. For the rest of the soils. K max ranged from 36.3 to 43.7 mg NO3 -N kg -1 d -1. Potential nitrification rate was negatively correlated (P < 0.01) with soil salinity and positively correlated with total organic C, microbial activity, and microbial biomass. Highly gypsiferous soil showed a low K max (8.9 mg NO3 -N kg -1 soil d -1) with the lowest NO3 -N content in field samplings (7 kg NO3 3- N ha -1 as an annual average). This fact demonstrated certain inhibition of the nitrification that can be attributed to unbalanced properties in the highly gypsiferous soil.     

Residues of atrazine, simazine, linuron and diuron after repeated annual applications in a peach orchard

Annual applications of the herbicides atrazine, simazine, linuron and diuron at 45 kg/ha were made to the same plots for 9 consecutive years from 1963 to 1971 in a peach (Prunus persica (L.) Batsch.) orchard located on sandy loam soil near Harrow, Ontario. Soil samples from these plots were collected in late October for the last 3 years (1969–1971) and trees were cut down in December, 1969. Herbicide residues were determined by bioassays based on the fresh and dry weight of oats (Avena sativa L.) and in one year results were confirmed by chemical analysis. Significant accumulation of herbicides was not observed. The maximum residue levels measured in October over the 3 years of sampling were 7′3 kg/ha for diuron, 3–8 kg/ha for linuron, 1–6 kg/ha for simazine and 04 kg/ha for atrazine in the top 15 cm of the soil profile. Simazine and atrazine showed a rapid decrease in amount after treatment but diuron and linuron were degraded more slowly. Measurable residues of all herbicides were confined to the upper 15 cm of the soil profile and the majority of herbicide remained in the 0–5-cm soil layer. Oats were planted in the orchard plots from 1972 to 1974 to follow the disappearance of the herbicides. All herbicides caused highly significant yield decreases in 1972, atrazine causing the least (38%) and diuron the greatest (86%) reductions. Diuron reduced the yield of oats in 1973 and caused a highly significant decrease in the weight of young oat plants in 1974.     

CHEMICAL CONTROL OF IMPERATA CYLINDRICA (L.) BEAUV. IN MALAYSIA*

Summary. Paraquat-based treatments were evaluated for the control of Imperata cylindrica (L.) Beauv., a perennial grass with extensive rhizomes of great regenerative power. Single applications of 0–5 lb/ac paraquat gave good initial control, but regeneration was rapid. Increases up to 2–0 lb/ac had little effect on the duration of control, nor did the volume rate from 40 to 120 gal/ac. When an initial application of 05 lb/ac was followed by two further applications of 0–25 lb/ac, when the level of control had decreased to 50%, lasting control was obtained. Application of 6–8 lb/ac dalapon followed by 0–25 lb/ac paraquat also gave good control, comparable with that achieved by the conventional treatment of dalapon alone at 15–20 lb/ac. La lutte chimique contre Imperata cylindrica (L.) Beauv. en Malaisie Résumé. Des traitements utilisant le paraquat ont étè essayés pour lutter contre Imperata cylindrica (L.) Beauv., graminée pérenne avec des rhizomes importants qui manifestent un pouvoir de régénération élevé, Des applications uniques de paraquat à la dose 0,56 kg/ha ement un bon eifel initial mais la régéneration fut rapide. L'accroissement de la dose jusquà 2,2 kg/ha n'eut qu'une faible incidence sur la durée de l'action herbicide, l'augmentation du volume de traitement de 450 à 1350 1/ha ne provoqua pas non plus d'augmentation de I'efficacité. Une seule application de paraquat à 0,56 kg/ha, quand le niveau de I'efficacité eut décru jusquà 50%, suivie de deux applications supplémen-taires à 0,275 kg/ha, donna une efficacité plus durable. Des applications de dalapon de 6,7 à 9,0 kg/ha suivies de traitements au paraquat à 0,275 kg/ha donnèerent un résultat aussi bon que celui obtenu par les traitements habituels au dalapon seul, à la dose dc 16 à 22 kg/ha. Chemisehe Bekampfung von Imperata cylindrica (L.) Beauv. in Malaysia Zusammenfassung. Es erfolgten Untersuchungen zur Bekämpfung von Imperata cylindrica (L.) Beauv., einem mehrjährigen Gras mit einem ausgedehnten Rhizomsystem und starker Regenerationskraft, mit Paraquat, Einmalige Applikation von 0,56 kg/ha Paraquat hatte zwar eine gute Anfangswirkung, doch erfolgte rasche Regeneration. Eine Erhöhung bis auf 2,2 kg/ha war ebenso wie eine Änderung der Spritzbrühmenge von ca 450–1350 I/ha von geringem Einfluss auf die Nachhaltigkeit der Bekämpfungs-massnahmen. Eine einmalige Anwendung von 0,56 kg/ha Paraquat gefolgt von zwei weiteren Applikationen von 0,28 kg/ha, wenn die Regeneration ungelahr 50% erreicht hatte, ergab nachhaltige Wirkung. Behandlungen mit 6,7-9 kg/ha Dalapon gefolgt von 0,28 kg/ha Paraquat hatten ebenfalis eine gute Wirkung, die mit der einer konven-tionellen Behandlung mit 16,8-22 kg/ha Dalapon vergleiehbar war.     

黄土丘陵沟壑区不同人工林地土壤肥力变化研究

通过对吴起县不同纯林及其交互效应混交林地的土壤调查、样品测定和室内分析,了解不同人工林地土壤肥力变化情况.结果表明0～20 cm表层土壤养分变化较大.其中,山杏×沙棘混交林地和山杏纯林地利于改善土壤有机质水平,分别达到20.79 g/kg和13.93 g/kg;山杏×小叶杨混交林地和小叶杨纯林地碱解氮含量增幅较大,分别为61.55 mg/kg和61.11 mg/kg;山杏×小叶杨混交林地有效磷含量相对较高,为5.43 mg/kg;山杏纯林地、山杏×小叶杨混交林地和小叶杨纯林地速效钾变化较为明显,分别为126.94,125.61和119.28 mg/kg.混交林地比纯林地更利于改善土壤肥力,建议种植山杏×沙棘混交林.     

草甘膦铵盐在苎麻田的残留及消解动态

建立了简单、灵敏的土壤及苎麻中草甘膦残留量的气相色谱检测方法。土壤样品用0.01 mol/L 的氢氧化钠水溶液提取,其他样品用水和丙酮提取,经阴离子交换柱(AG1-X8)净化,与原乙酸三甲酯(TMOA)和冰醋酸反应,用气相色谱带火焰光度检测器(FPD)检测,外标法定量。结果表明:当草甘膦在麻蔸和土壤中的添加水平在0.05~1 mg/kg时,添加回收率分别为 73.6%~102.6% 和85.9% ~105.1%,相对标准偏差分别为2.3% ~8.1% 和5.4% ~13.0%。草甘膦的最小检出量(LOD)为0.5×10-10 g,在麻蔸中的最低检测浓度(LOQ)为0.05 mg/kg。2年3地的残留试验结果表明:草甘膦铵盐在湖南省、广西壮族自治区及福建省土壤中的半衰期分别为1.6~2.6 d,1.0~1.8 d和1.1~1.5 d。无论是在高浓度处理区 还是在低浓度处理区 ,苎麻收获时(距施药60 d),土壤和麻蔸样品中均未检出草甘膦铵盐。     

Toxicity and dissipation of soil insecticides applied in the management of arecanut white grub, <Emphasis Type="Italic">Leucopholis burmeisteri</Emphasis> Brenk. (Coleoptera: Scarabaeidae)

White grubs, Leucopholis spp. are subterranean pests of arecanut grown in South India. Grub infestation leads to yellowing, stem tapering, and crown size and yield reduction. Use of chemical insecticide to mage the white grubs gives varying degree of success. Hence an attempt was made to screen newer and safer insecticides. Imidacloprid (LC₅₀ at 120 h = 16.849 ppm on III instar larvae), chlorpyriphos (LC₅₀ = 14.242) and bifenthrin (LC₅₀ = 12.797 ppm) were identified as effective insecticides. Evaluation of these insecticide in the field over two year period indicated the following efficacy in reducing larval population: chlorpyriphos @ 4 kg a.i/ha (83.31%) > bifenthrin @ 4 kg a.i./ha (82.83%) > imidacloprid @ 0.24 kg a.i./ha (75.84%) > bifenthrin @ 2 kg a.i./ ha (74.26%) > chlorpyriphos @ 2 kg a.i./ha (69.15%) > chlorpyriphos @ 1 kg a.i./ha (61.79%) > imidacloprid @ 0.12 kg a.i./ha (56.54%) > bifenthrin @ 1 kg a.i./ha (54.34%) > imidacloprid @ 0.06 kg a.i./ha (41.47%). Bifenthrin in soil persisted for a longer period than chlorpyriphos. On the day of application, 59.46 ppm bifenthrin residue was recovered from soil. On 10th day, it was 7.29 ppm which decreased to 2.59 ppm on 30th day and was beyond detection limit on 65th day. Chlorpyriphos exhibited a rapid degradation in the initial stage; 27.46 ppm residue on the day of application, which further reduced to 0.964 ppm on 10th day, and was below the detection limit on the 30th day. Growth of Trichoderma harzianum was not affected by bifenthrin even up to 40 ppm concentration. However, chlorpyriphos affected the growth of Trichoderma at higher than 5 ppm dose. Similarly, imidacloprid inhibited the colony growth from 2 ppm onwards. Having high lipophylic property and contact toxicity, bifenthrin would be an ideal alternative insecticide to chlorpyriphos for the management of white grubs in palm garden, which is safe and long persisting.     

Chemical control of Eleusine indica and other weeds in Setaria anceps

In field experments on the Altherton Tableland. Queensland. Auslralia, methabenzthiazuron used at 1 2 kg ha pre-emergence was the most effective herbicide for selectively controlling Eleusine indica (L.) Gaertn in seed crops of Setaria anceps Stapf. Bromoxynil. bromoxynil plus MCPA, simazine and terbutryne were either ineffective or phytotoxic to S anceps. A more reliable technique was the use of diuron applied at 2.8 kg ha pre-emergence when the crop row was physically protected with metal shields at spraying or when activated carbon applied as a slurry in water at 168 kg per sprayed ha was sprayed in a 3 cm wide band over the crop row at sowing Three successive applications of paraquat over a 39 day period prior to sowing the crop were necessary for effective control of E. indica using the ‘stale seed bed’ technique     

Metribuzin mobility in soil columns as affected by urea fertiliser

Application of urea fertilisers to soils influences the soil solution characteristics and thus may affect the sorption of soil-applied herbicides. The present investigation reports the influence of urea co-application on sorption and leaching of metribuzin, a triazine herbicide. Urea application at 60 and 120 kg N ha(-1) increased metribuzin sorption in soils over that in untreated natural soil. The Kf (Freundlich adsorption coefficient) values of metribuzin for natural, 60 and 120 kg N ha(-1) treatments were 0.43, 0.46 and 0.84 microg(1 - 1/n) g(-1) ml1/n respectively. Downward mobility of metribuzin was studied in packed soil columns (300 mm length x 59 mm i.d.) at two irrigation intensities, 720 m3 ha(-1) (72 mm) and 3600 m3 ha(-1) (360 mm). After 720 m3 ha(-1) irrigation, metribuzin did not leach out of any column and was not detected in the leachate. Urea amendment slowed the leaching of metribuzin by 20 and 40% in 60 and 120 kg N ha(-1) urea-treated columns respectively. Also, following urea application, greater amounts of metribuzin were retained in the application zone. Upon increasing the irrigation intensity fivefold, urea application did not have any effect on metribuzin mobility, and its breakthrough from both natural and urea-amended columns occurred after 126 mm irrigation. However, there was a marked difference in the maximum concentration of metribuzin in the breakthrough curves obtained from natural and urea-amended columns. The study indicated that co-application of metribuzin and urea fertiliser is a safe practice as far as leaching of herbicide is concerned.     

RESIDUAL ACTIVITY OF PARAQUAT IN SOILS II. ADSORPTION AND DESORPTION

Glasshouse studies showed that low doses of paraquat inhibited the germination of Lolium perenne L. broadcast directly onto the paraquat-sprayed surfaces of a sphagnum and a peat soil, but that higher doses were necessary to produce phytotoxic symptoms on mineral soils, a compost and a loam. On all soils residual activity increased rapidly with increasing dose once the minimum phytotoxic dose was reached. On a sandy soil, residual activity increased almost linearly from the lowest to the highest dose applied. At 9·0, 4·5 and 2·24 kg/ha phytotoxicity on a compost was not affected by changes in the volume of application, but at 1·68 kg/ha and lower, reducing the volume from 562 1/ha to 281 and 112 1/ha resulted in increased phytotoxicity. Phytotoxic residues were eluted from paraquat-treated compost surfaces by percolating de-ionized water up soil columns but residual activity was not removed from the eluted surfaces. Surface irrigation of paraquat-treated surfaces with water previously percolated through columns of untreated soil reduced residual activity by 45%.     

Residues of diflubenzuron and two of its metabolites in a forest ecosystem after control of the pine looper moth,Bupalus piniarius L

Diflubenzuron, 1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)urea was used to control the pine looper population in about 1160 ha of Scots pine stand in eastern Finland in summer 1984. The control measure was effective, resulting in the collapse of the population in the treated area. Residues of diflubenzuron and two of its metabolites, 4-chloroaniline and 4-chlorophenylurea, were determined in water, pine needles, litter, humus, boleti and other wild mushrooms, bilberry (Vaccinium myrtillus L.) and cowberry (Vaccinium vitis-idaea L.) samples taken from this area. In water samples taken from the treated area diflubenzuron was still detected at concentrations of 0.1 μg litre^?1 2 months after application. No diflubenzuron was detected in this area the following year, nor outside the treated area. Neither metabolite was detected at any time. The sum of diflubenzuron and its metabolites in the litter layer was, on average, 0.7mg kg^?1 both 1 week and 1 month after the application. The next year, however, it had increased to 1.4 mg kg^?1. Diflubenzuron and its metabolites were not detected in the humus layer. The amount of diflubenzuron residues in the pine needles was, on average, 3.0 mg kg ^?1 1 day after the application, but in 2 months the level had decreased to 0.2-0.3 mg kg ^?1 or was not detectable. The following year the sum of diflubenzuron and its metabolites in two pine-needle samples was 0.3 and 1.6 mg kg ^?1. The sum of diflubenzuron and its metabolites in wild mushrooms was, on average, 0.07 mg kg ^?1 1 week after the application, but the following year no residues were detected. No residues were found in the boletus samples. The residues of diflubenzuron and its two metabolites in bilberries totalled, on average, 0.2 mg kg ^?1 1 day after the application, and 6 μg kg ^?1 the following year. The sum of diflubenzuron and metabolites in cowberries was, on average, 0.2 mg kg ^?1 1 month after application.     

Persistence of dichlobenil in a sandy soil and effects of residues on plant growth

The persistence of dichlobenil following the application of dichlobenil granules was studied in a replicated plot experiment including both surface and incorporated treatments of 8·3 and 16·6 kg/ha ai. Soil analyses showed an initial half-life of about 4 weeks but the persistence increased with time and a year after application the half-life was about 1 year. Incorporation of the granules into the soil markedly increased the persistence of dichlobenil and its metabolite dichlorobenzamide. The most sensitive crop was carrot which was damaged by residues of only 1–2% of the recommended dose. Residues phytotoxic to carrots persisted for 2 years from the 8·3 kg/ha surface application and 5 years from the 18·6 kg/ha incorporated application. Lettuce was also highly sensitive to residues.     

Effect of naptalam on growth of yellow nutsedge and subsequent control with glyphosate*

Naptalam applied to yellow nutsedge (Cyperus esculentus L., var leptostachvus Boeck.) plants through nutrient culture, as a foliar spray or to the soil surface significantly stimulated the transformation of rhizomes into new shoots when the plants were grown under a 20-h photoperiod. Applications of naptalam to plants grown under short-day conditions inhibited tuber production. Applications of glyphosate to yellow nutsedge foliage at 0·3 and 0·6 kg ha resulted in 57 and 68% dormant tubers respectively, compared to 27% in untreated plants. These lower rates did not significantly increase the number of nonviable tubers. The application of 1·1 and 2·2 kg ha resulted in 47 and 52% dormant tubers, respectively and approximately 40% nonviable tubers. When production of new shoots of yellow nutsedge was induced by soil treatment with napialam and followed later with glyphosate significantly greater control of the nutsedge was observed than from either herbieide alone. Effets du naptalame sur la crossance du experus aune et efficaeite ulterieure du glyphosate. Le naptalame appliquè sur des plantes de cypérus jaune (Cyperus esculentus L. var leptostachyus Boeck) a vee des éléments nutritifs, en pulvérisation fobaire ou à la surface du sol a significativement stimulé la transformation des rhizomes en nouvelles pousses forsque les plantes ont été soumises à une photopériode de 20 h. Les applications de naptalame aux plantes pousant dans des conditions de jours courts ont inhibe la production des tubercules. Des applications de glyphosate sur le feuillage du cypérus jaune à 0.3 et 0.6 kg ha ont donné respectivement 57 et 68% de tubercules dormants contre 27% chez les plantes non traitées. Ces doses plus faibles n'ont pas augmente significativement le nombre de tubercules nonviables. L'application de 1.1 et 2.2 kg ha a donné respectivement 47 et 52% de tubercules dormants, et approxativement 40% de tubercules non viables. Lorsque la production de nouvelles pousses de cypérus jaune a été induite par un traitement du sol au naptalame. suivi ulterieurement d'une application de glyphosate. l'efficacite observée sur le cypérus a été significativement meilleure qu'avee l'un ou l'autre de ces herdicides employé soul. Der Einfluss von Naptalam auf das Wachstum von Cyperus esculentus L. und nachfolgender Bekämpfung mit Glyphaxate Wird Naptalam in die Nähelösungskultur oder auf das Blatt von Cyperus esculentus var leptostachyus Boeek, sowj?e auf die Bodenoberfläche appliziert so stimulieri es die Bildung von neuen Trieben aus Rhizomen, wenn die Pflazen einer Photoperiode von 20 Std. ausgesetzt werden. Unter Kurztagshedingungen hemmt Napralam die Bildung von Knollen Wurde Naptalam auf die Blätter mít 0.3 und 0.6 kg ha appliziert so stieg die Zahl der dormanten Knollen von 27% bei unbehandelt auf 57% und 68% bei behandelt. Diese niedrigen Aufwandmengen steigerten die Zahl der keimfähigen Knollen nicht significant. Die Applikation von 1.1 und 2.2 kg ha resultiere in 47 und 52% dormanten und 40% nicht keimfähigen Knotlen. Wenn die Bildung von Trieben durch eine Behandlung mit Naptalam über dem Boden induziert wurde und diese nachfolgend mit Bekämpfungserfolg als wenn jades Herbizid allein angewandt wurde.     

Influence of methyl bromide soil fumigation method on fungicidal efficacy and bromide residues

Highest inorganic bromine residues (30 ppm) were found when soil was fumigated with liquid methyl bromide (MB) introduced by conventional means into evaporating dishes. With preheated (vaporized) MB or injection of MB/chloropicrin (CP) mixtures, bromide concentrations were reduced by 50%. They were uniform throughout the soil (0 to 60 cm) except after MB/CP injection, when larger residues were found in the 30-60 cm layer. Leaching with 2000 m^p3/ha (20 cm) of water always reduced bromide content to 7.5 and 10 ppm at the 0-30 and 30-60 cm depth, respectively. Organic amendments to soils substantially increased bromide levels up to 118 ppm, most of which was found in the upper soil layers; two teachings with 2000 m^p3 /ha water were required to return the soils to their normal state.Sclerotium rolfsii andFusarium oxysporum f. sp.dianthi cultures buried in soil were eliminated from the upper 30 cm with MB applied either conventionally or preheated. At 50 cm, 500 kg/ha of the preheated gas was superior to 1000 kg/ha of the cold gas. All MB fumigations suppressed carnation flower yields compared with CP alone but were superior to no treatment. After leaching, MB-fumigated soils yielded the highest number of flowers.     

Factors influencing the control of bracken (Pteridium aquilinum(L.) Kuhn) with asulam

In three experiments at two sites the influence of date of application, dose and additives on activity of asulam on bracken (Pieridum aquilinum) was investigated Asulam was only effective when it was applied to live bracken foliage. Of the foliar treatments. July applications were more effective than those applied in June or September. A dose of 1-1 kg/ha asulam gave inadequate control but 2-2 kg/ha and above applied in July gave good control. Increasing the dose increased the degree of control and also lowered the rate of regeneration. Adding 0·5%, Agral 90 or tributyl phosphate at 0·25%, and 0·5%, with or without Agral 90 at 0·5%, had little useful effect on asulam activity, 4·5 kg/ha dicamba or aminotrizole given in July were less effective than asulam at 2·2 kg/ha. Dicamba was the most active of the herbicides tested in the absence of viable bracken foliage. Facteurs influençant l'action de l'asulame sur la fourgére aigle (Pteridium aquilinum (L.) Kuhn) Dans trios essays studés en deux endroits différents, les auteurs ont étudié l'influence de la date d'application de la dose et de divers additives sur l'efficacité de l'asulame contre la fourgére aigle (Pteridium aquilinum). L'asulame n'a été efficace que lorsqu'il a été appliqué sur le feuillage vivant de la fourgére. Parmi les traitements foliaires, ceux effectués en juillet ont été plus efficacies que ceux effectués en juin ou septembre. Une dose d'asulame de 1.1 kg/ha n'a pas n'a pas donné de bons résultats, mais la dose de 2.2 kg/ha appliquée en juillet s'est montrée efficace. L'accroissement de la dose a augmenté l'efficacité et a baissé le taux de régénération. L'addition d'Agral 90 á 0.5% ou de tributyl phosphate á 0.25% et 0.50% avec ou sans Agral 90 á 0.50% n'a pratiquement pas eu d'influence sur l'activité de l'asulame. Une dose de 4.5 kg/ha de dicamba ou d'aminotriazole apportée en juillet s'est montrée moins efficace que l'asulame à 2.2kg/ha. Le dicamba a été le plus efficace des herbicides essayés sur la fougére en l'absence de feuillage vivant. Einflussgrössen bei der Bekämpfung von Adlerfarn (Pteridium aquilinum (L.) Kuhn) mit Asulam In drei Experimenten an zwei Standorten wurde der Einfluss von Bekämpfungszeïtpunkt, von der Aufwandmenge und von Additiven auf die Wirkung von Asulam auf Adlerfarn (Pteridium aquilinum) unterucht. Asulam Zeigte nur dann eine Wirkung, wenn es auf lebendes Blattwerk des Farns ausgebracht wurde. Blattbehandlungen im Juli waren erfolgreicher als solche im Juni order September. Aufwandmengen von 1.1 kg/ha. Asulam führten zueinem unzulänglichem, von 2.2 kg/ha und darüber. im Juli ausgebracht, zu einem guten Bekämpfungserfolg. Mit zunehmender Aufwandmenge wurde der Bekämpfungserfolg verbessert und die Regenerationsrate verringert. Die Zumischung von 0.5% Agral 90 order von 0.25% und 0.5% Tributylphosphat mit order ohne Zusatz von 0.5% Agral 90 zeigten nur einen geringen Nutzeffeki auf die Asulamaktrivität. Dicamba order Aminotriazol (4.5 kg/ha). im Juli ausgebract, war weniger wirkungsvoll als Asulam mit 2.2 kg/ha. Von den Herbiziden, mit denen bei Nichtvorhandensein lebender Farnblätter Versuche angestellt wurden, war Dicamba das aktivste.