Cyhalofop application timing and adjuvant selection for Echinochloa crus-galli control in rice

Field experiments were conducted in Stuttgart, Arkansas, in 2007 and 2008 to evaluate cyhalofop application timing and adjuvant selection for Echinochloa crus-galli L. Beauv. (barnyardgrass) control in drill-seeded rice. In the application timing experiment, cyhalofop was applied at 1 d prior to flooding (PREFL) and at 7, 14, and 21 d post-flood (POSTFL) as single (314 g a.i./ha) or sequential application (first application at 314 g a.i./ha followed by a second application 14 days later at 213 g a.i./ha). In the adjuvant study, the adjuvants evaluated were non-ionic surfactant (NIS) at 0.25% v/v, crop oil concentrate (COC) at 1% v/v, methylated seed oil (MSO) at 1% v/v, 28% urea ammonium nitrate (UAN) at 2.5% v/v, combination of NIS or COC or MSO with UAN, a proprietary blend of MSO/organosilicone (OSL)/UAN at 2.5% v/v, and MSO/OSL/UAN applied with NIS or COC. All adjuvants applied with cyhalofop (314 g a.i./ha at 14 d after flood establishment) resulted in E. crus-galli control and rice yields comparable to cyhalofop alone. In 2007, a single application of cyhalofop controlled E. crus-galli 98–100% by the end of the season, except in the 14-d POSTFL timing (90%). In 2008, E. crus-galli plants were more robust, and control was inconsistent and less than in 2007 (10–91%). At the PREFL timing, sequential applications were needed to improve end-of-season E. crus-galli control. The 7-d POSTFL timing was one of the best single application timings for increased E. crus-galli control and rice yield. Delaying the cyhalofop application to 21-d POSTFL resulted in unacceptable E. crus-galli control of 10 and 46% with single and sequential programs, respectively. Average rice yield was reduced almost three-fold when the first cyhalofop application was at 21-d POSTFL compared with 7-d POSTFL.     

Effect of spraying selected pesticides on the contents of specified minerals in cabbage

The present study was conducted to assess the effect of spraying of pesticides on the content of minerals in cabbage harvested at varying waiting periods (0, 7, 14 and 21 days) after spraying. The amounts of phosphorus and zinc in cabbage were significantly (p < 0.05) decreased while those of iron, calcium and potassium were significantly (p < 0.05) increased by the sprayings of pesticides. At varying waiting periods after the spraying of pesticides calcium, phosphorus, zinc and potassium contents of cabbage were found to be decreased remarkably (p < 0.05) while the content of iron was increased significantly (p < 0.05). Between the two pesticides, the spraying of endosulfan exerted a more pronounced effect in altering the contents of minerals than the spraying of malathion.     

Differential tolerance of weedy red rice (Oryza sativa L.) from Arkansas, USA to glyphosate

Red rice (Oryza sativa L.), a weedy relative of cultivated rice (O. sativa), is a troublesome weed in rice in the southern United States. It is also very problematic in other world regions where rice is grown. There are many types of red rice. Some have white pericarp. In this paper, the term ‘red rice’ will be used to refer to the weedy types that occur in this region of the southern USA. Because of the great diversity in morphology and phenology of red rice populations in the USA, we hypothesized that these have differential tolerance to glyphosate. Red rice is subjected to selection pressure by glyphosate, which is the principal herbicide used in glyphosate-resistant soybean planted after rice. Two hundred-fifteen red rice accessions were collected in Arkansas, USA between 2002 and 2003 and evaluated for glyphosate tolerance between 2003 and 2006. The commercial dose of glyphosate controlled red rice accessions 81-100% regardless of application timing, by 30 d after treatment. The number of survivors that produced seeds and the seeds produced per survivor differed between accessions. Application of the full dose at the tillering stage was more effective than at the 3- to 4-leaf stages. At half the field dose, 40 to 54% of survivors produced seed, with germination capacity of 30-100%. The lowest dose of glyphosate, 225 g a.e. ha⁻¹, resulted in the widest range of control ratings from 30 to 100%. The red rice accessions differentiated into six tolerance categories. A tolerance map was generated and will be used in educating growers about the proper use of glyphosate for red rice management.     

The effect of low dose ultraviolet light-C seed treatment on induced resistance in cabbage to black rot (Xanthomonas campestris pv. campestris)

Low doses of hormetic (n. hormesis) ultraviolet light-C (UV-C) seed treatments were used to elicit host resistance to black rot, and improve the quality and growth response of cabbages in greenhouse studies. Different UV-C doses (1.3 to 7.5 kJ m⁻²) were tested to determine their ability to induce resistance to black rot. The optimum UV-C dose of 3.6 kJ m⁻² was effective in reducing black rot and the population density of Xanthomonas campestris pv. campestris in infected cabbage leaves. Seeds treated with UV-C at 3.6 kJ m⁻² produced plants with the most desirable color, highest weight, largest head diameter and delayed maturity. The effect of storage time at room temperature on disease incidence of black rot of cabbage from seeds treated with a low hormetic UV-C dose of 3.6 kJ m⁻², was 90%, 40%, 60% and 60% reduction of black rot in plants from UV-C treated seeds stored for 2 days, 1, 5, and 8 months, respectively, 8 weeks after transplanting cabbage plants.     

Antifeedant and toxic effects of naturally occurring and synthetic quinones to the cabbage looper, Trichoplusia ni

We investigated the feeding deterrent effects and toxicity of naturally occurring and synthetic quinones to the cabbage looper, Trichoplusia ni. Feeding deterrent effects were determined via a leaf disc choice bioassay. Based on DC₅₀ values, 1,4-naphthoquinone was the most active antifeedant (DC₅₀ = 1.8 μg/cm²) followed by juglone (DC₅₀ = 2.1 μg/cm²), 2-methoxy-1,4-naphthoquinone (DC₅₀ = 2.6 μg/cm²), plumbagin (DC₅₀ = 3.3 μg/cm²), and 2,3-dimethoxy-5-mehtyl-1,4-benzoquinone (DC₅₀ = 4.2 μg/cm²) in third instar cabbage looper larvae. 2-Bromo-1,4-naphthoquinone, 2-chloro-3-morpholino-1,4-naphthoquinone, 1,8-dihydroxy-anthraquinone, 2-methyl-1,4-naphthoquinone and naphthazarin had DC₅₀ values ranging from 8.4 to 10.1 μg/cm². Juglone and plumbagin were able to provide protection to intact cabbage plants in a greenhouse experiment. Cabbage looper larvae consumed less leaf area and weighed less on cabbage plants treated with either of these naturally occurring quinones. Most of the quinones demonstrated levels of antifeedant activity greater than neem, a positive control, in laboratory bioassays. The level of activity for juglone was comparable to neem in the greenhouse experiment. There was also a reduction in the number of larvae on treated plants compared with the negative control. Structure-activity relationships suggest that the antifeedant effects of the tested quinones depend on the number and position of hydroxyl and methoxyl substituents of quinones. Most of the quinones were of medium-low toxicity to third instar cabbage looper larvae via topical administration. Some of these quinones could have potential for development as commercial insect control agents targeting the feeding behavior of insects with minimal toxicity, provided that their impacts on non-target organisms and environment are minimal.     

Survival of cabbage looper, Trichoplusia ni (Lepidoptera: Noctuidae), through winter cleanups of commercial vegetable greenhouses: Implications for insecticide resistance management

Cabbage looper, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae), is a highly migratory and destructive pest of various crops in North America. Its infestations in vegetable greenhouses in western Canada are generally attributed to annual immigrations from southern overwintering areas, but whether it survives overwinter in western Canada is uncertain. Bioinsecticides based on Bacillus thuringiensis (Bt) toxins are commonly used in southwestern British Columbia where some T. ni populations have developed strong resistance to Bt-insecticides. In this study, overwintering success of T. ni populations was monitored outside and inside three commercial greenhouses in British Columbia. In both years, T. ni pupae placed outside greenhouses did not survive although pupae placed inside the greenhouses survived the unheated cleanup period and exposure to organophosphate insecticides commonly used in the cleanup procedure in the greenhouses. During the cleanup period, no moths were caught inside the unheated greenhouses, but once the heating was restored for the new growing season, adults were captured in pheromone traps. No developmental stages of T. ni were detected on nursery seedlings and visual monitoring of transplants at the beginning of the season found no signs of previous feeding damage. This strongly suggests that T. ni were not introduced with the seedlings. Our findings are important for understanding the potential risks of inadequate winter cleanup and the potential carryover of resistance to Bt-insecticides in populations from one season to the next that could complicate pest management.     

Effects of method, rate and timing of slurry application to grassland on the preference by cattle for treated and untreated areas of pasture

Two experiments were conducted in the UK to investigate preference by cattle for areas of pasture treated or untreated with dairy cow slurry. Experiment 1 examined the effects of method and rate of slurry applied to a grass pasture in March (Spring); Experiment 2 examined the effects of method and timing of slurry application after cutting for silage in June (Summer). In both experiments, beef steers grazed grassland plots that had been treated with slurry on one half only of the plots for 4 weeks. Slurry was applied by shallow injection (I), trailing shoe (T) or conventional surface broadcasting (S) techniques. In Experiment 1, slurry was applied at 40 m³ ha^?1 (HI) or 20 m³ ha^?1 (LO) 21 d before grazing commenced; in Experiment 2, slurry was applied at 20 m³ ha^?1 either 32 d (E) or 10 d (L) before grazing commenced. Sward height was measured and animal behaviour was recorded during 8 × 24 h measurement periods in each experiment. Preference for slurry‐treated or untreated swards was indicated by a comparison of post‐grazing sward height on each sward and the proportion of total grazing time spent on the slurry‐treated swards. In Experiment 1, a smaller proportion of grazing time was spent on slurry‐treated areas of swards compared with untreated areas of swards on all treatments, but the proportion of time spent grazing the slurry‐treated sward was greater on method T than on methods I or S (0·28, 0·31 and 0·39 for methods S, I and T, respectively, s.e.d. = 0·035, P < 0·05). Steers showed no preference between slurry‐treated and untreated swards by 49, 45 and 44 d after slurry application for methods S, I and T respectively. Differences between HI and LO were not significant (P > 0·05). In Experiment 2, aversion to slurry‐treated swards compared with untreated swards was less for treatment E than for L, with a greater proportion of both residence and grazing time spent on the slurry‐treated sward of treatment E than L (0·43 and 0·28, respectively, for residence time, s.e.d. = 0·025, P < 0·001, and 0·47 and 0·30, respectively, for grazing time, s.e.d. = 0·021, P < 0·001). Significant differences were shown between the methods of slurry application for treatment E, with a greater proportion of grazing time spent on the slurry‐treated swards of methods I and T than method S (0·40, 0·52 and 0·49 for S, I and T, respectively, s.e.d. = 0·032, P < 0·001), and a greater difference between post‐grazing heights on slurry‐treated and untreated swards for method S than for I or T (30, 12 and 15 mm, respectively, s.e.d. = 4·8, P < 0·001). For treatment L, differences in the proportion of time spent grazing on slurry‐treated swards compared with untreated swards were not significant between treatments (0·26, 0·34 and 0·31 for methods S, I and T, respectively, s.e.d. = 0·040, P > 0·05) and indifference between slurry‐treated and untreated swards was achieved 77, 60 and 58 d after slurry spreading for methods S, I and T respectively. These results show that, when slurry is applied to pasture in a grazing rotation, the adverse effects on grazing behaviour associated with conventional surface broadcasting may be overcome by the use of novel slurry application techniques.     

Effect of planting date,fungicide timing and cultivar susceptibility on severity of narrow brown leaf spot and yield of rice

Narrow brown leaf spot (NBLS) of rice (Oryza sativa L.) is caused by Cercospora janseana (Racib). O. Const. (Synonyms: Cercospora oryzae Miyake, Passalora janseana Racib. U.). Experimental studies were conducted at Rice Research Station, Louisiana State University, and Agricultural Center, Crowley, to manage NBLS by fungicide application of propiconazole at different growth stages of rice cultivars having different susceptibility levels to NBLS in different planting dates. Results of these studies revealed that April (early) had less NBLS severity as compared to May (late) planting. Very susceptible cultivars, CL131 and Cheniere, had the highest and resistant cultivars, Della and Presidio, had the lowest NBLS severity at both the planting dates. Propiconazole application significantly reduced the NBLS severity in comparison to untreated. Fungicide application at panicle initiation was the most effective time to manage NBLS on the very susceptible and susceptible cultivars at both planting dates. NBLS on moderately susceptible cultivars was best managed by applying fungicide either at panicle initiation or early boot stage in early planting but panicle initiation was the best time to apply fungicide in late planting. Resistant cultivars did not need fungicide in April planting but did need in May planting. Rice yield was determined to be higher in April than May planting. Fungicide application at early boot stage protected the yield by 9.4% in April planting and 34.2% when applied at panicle initiation in May. Susceptible cultivar, Cheniere, exhibited the greatest yield and resistant cultivars had lowest yield in both the planting dates regardless of its susceptibility level to NBLS. Yield of very susceptible to susceptible cultivars was reduced in late planting but no effect was observed on yield of moderately susceptible and resistant cultivars.     

The effects of rate and timing of application of fertilizer nitrogen in late summer on herbage mass and chemical composition of perennial ryegrass swards over the winter period in Northern Ireland

A small‐plot experiment was carried out in Northern Ireland on a predominantly perennial ryegrass sward over the period July 1993 to March 1994 to investigate the effect of timing and rate of fertilizer nitrogen (N) application on herbage mass and its chemical composition over the winter period. Eighty treatment combinations, involving four N fertilizer application dates (28 July, 9 and 30 August and 20 September 1993), four rates of N fertilizer (0, 30, 60 and 90 kg N ha^?1) and five harvest dates (1 October, 1 November, 1 December 1993, 1 February and 1 March 1994), were replicated three times in a randomized block design experiment. N application increased herbage mass at each of the harvest dates, but in general there was a decrease in response to N with increasing rate of N and delay in time of application. Mean responses to N applications were 13·0, 11·5 and 9·5 kg DM kg^?1 N at 30, 60 and 90 kg N ha^?1 respectively. Delaying N application, which also reduced the length of the period of growth, reduced the mean response to N fertilizer from 14·3 to 7·4 kg DM kg^?1 N for N applied on 28 July and 20 September respectively. Increasing rate of N application increased the N concentration and reduced the dry‐matter (DM) content and water‐soluble carbohydrate (WSC) concentration of the herbage but had little effect on the acid‐detergent fibre (ADF) concentration. Delaying N application increased N concentration and reduced DM content of the herbage. The effect of date of N application on WSC concentration varied between harvests. A decrease in herbage mass occurred from November onwards which was associated with a decrease in the proportion of live leaf and stem material and an increase in the proportion of dead material in the sward. It is concluded that there is considerable potential to increase the herbage mass available for autumn/early winter grazing by applying up to 60 kg N ha^?1 in early September.     

Application timing and adjuvant type affected saflufenacil efficacy on selected broadleaf weeds

Saflufenacil is a new herbicide being developed for pre-plant burndown and pre-emergence broadleaf weed control in field crops, including maize, soybean, sorghum and wheat. Field experiments were conducted in 2007 and 2008 in northeast Nebraska, USA to describe dose-response curves of saflufenacil applied in mid (early post-emergence, EPOST) and late May (late post-emergence, LPOST) with several adjuvants for spring emerging broadleaf weed control. Dose-response curves based on log-logistic model were utilized to determine the ED₉₀ values (effective dose that provides 90% weed control efficacy) for Convolvulus arvensis, Lactuca serriola, Lamium amplexicaule, Capsella bursa-pastoris, Taraxacum officinale, Thlaspi arvense and Conyza canadensis. In general, weed control efficacy was influenced by application timing and type of adjuvant. EPOST application of saflufenacil resulted better efficacy of saflufenacil compared to LPOST. Addition of spray adjuvants improved efficacy of saflufenacil. For example, 90% control of T. arvense was obtained at EPOST application with 251, 161, 96 and 59 g a.i. ha⁻¹ for saflufenacil applied alone, or tank-mixed with NIS (nonionic surfactant), COC (crop oil concentrate), or MSO (methylated seed oil), respectively. In contrast, the ED₉₀ values with LPOST application were 333, 201, 127 and 79 g a.i. ha⁻¹ for saflufenacil applied alone, or with NIS, COC and MSO, respectively. MSO was the best adjuvant, which provided the most enhancement of saflufenacil. COC was the second best, or similar to MSO, on many weed species. NIS provided the least enhancement of saflufenacil. The ED₉₀ values determined for different broadleaf weed species are within the proposed label dose of saflufenacil.     

氮肥基追比对淮北地区超高产小麦产量和品质的影响

为探讨淮北地区小麦超高产栽培适宜的氮素运筹技术,在2006-2008年,以强筋小麦济麦20、烟农19和中筋小麦皖麦50为材料,在超高产(公顷产量9 000 kg以上)栽培条件下,研究了氮素不同基追比例对小麦产量、品质及植株养分含量的影响.结果表明,在每公顷施纯氮307.5～322.5 kg(其中化肥氮270 kg)、基追比例10∶0～4∶6范围内,济麦20、烟农19和皖麦50的籽粒产量、穗粒数、千粒重均随拔节期追氮比例的增大而递增,并与此期追氮比例呈极显著简单直线正相关或二次曲线相关;蛋白质含量、湿面筋含量、沉降值等品质指标均随拔节期追氮比例增加而提高.烟农19和皖麦50的植株体内含氮量随生育进程而渐降,分蘖期最高,成熟期降至最低.以上结果说明,淮北地区小麦实现超高产栽培的氮素运筹方式以氮肥总量的40%～50%基施、50%～60%拔节期追施为宜,传统的氮素"一炮轰"运筹方式难以达到9 000 kg/ha的超高产水平.     

Effect of imazamox plus bentazon on dry bean (Phaseolus vulgaris L.)

Imazamox plus bentazon has the potential to provide broad spectrum weed control in dry bean (Phaseolus vulgaris L.). Field trials were conducted in Ontario over a two year period (2003 and 2006) to evaluate the effect of imazamox plus bentazon applied post-emergence at 25 + 600 and 50 + 1200 g ai ha⁻¹ on black, brown, cranberry, kidney, otebo, pinto, white and yellow eye beans. Treatments included a non-treated check. All treatments were maintained weed free during the growing season. The eight market classes responded similarly to imazamox plus bentazon. Imazamox plus bentazon applied post-emergence caused less than 4% visible injury at 7, 14 and 28 days after treatment. Imazamox plus bentazon applied post-emergence did not have any effect on plant height, shoot dry weight, seed moisture content and yield of dry bean. Based on these results, imazamox plus bentazon at the proposed maximum use dose can be safely used for weed management in black, brown, cranberry, kidney, otebo, pinto, white and yellow eye bean production in Ontario. Additional research is needed to determine if cultivars within a market class of dry bean differ in their response to imazamox plus bentazon.     

花生蛋白粉的制取及在食品工业中的应用

研究了低温脱脂花生蛋白粉的生产工艺，并对产品的功能性及营养成分进行测定。结果表明，低温脱脂花生蛋白粉的水溶性蛋白含量、氮的可溶性指数高于其他脱脂方法的花生蛋白粉；脱脂花生蛋白粉的起泡性、吸油性、泡沫稳定性优于大豆蛋白粉，蛋白质、脂肪、含硫氨基酸含量高于大豆蛋白粉，但赖氨酸偏低。花生蛋白粉可用于肉类制品、谷物焙烤制品、饮料、冷食以及副食品、调味品和休闲食品。     

辣子草水浸液对白菜种子萌发和幼苗生长的影响

【目的】研究辣子草对蔬菜的化感作用。【方法】以白菜为对象,研究不同浓度、不同部位的辣子草水浸液对其种子发芽率及幼苗根长和苗长的影响。[结果]随着浓度的增加,辣子草的水浸液对白菜不同部位生长的抑制作用逐渐增强;而在同一浓度下,不同部位辣子草的水浸液对白菜的影响为叶〉茎〉根。【结论】辣子草对白菜具有化感作用,且该化感物质可能主要存在于辣子草的地上部分。     

Effect of application timing and grass height on the nitrogen fertilizer replacement value of cattle slurry applied with a trailing‐shoe application system

This study investigated the effect of using a trailing‐shoe system to apply cattle slurry, under different conditions of grass height (low [LG]: freshly cut sward [4–5 cm height] vs. high [HG]: application delayed by 7–19 d and applied to taller grass sward [4–11 cm] height) and month of application (June vs. April), on the nitrogen fertilizer replacement value (NFRV) and apparent N recovery (ANR_S) of cattle slurry applied to grassland. NFRV was calculated using two methods: (i) NFRV_N based on the apparent recovery of slurry‐N relative to that of mineral‐N fertilizer; and (ii) NFRV_DM based on DM yield. The effect of applying slurry into HG swards, relative to LG swards, decreased the DM yield by 0·47 t ha^?1 (P ≤ 0·001), N uptake by 5 kg ha^?1 (P = 0·05), ANR_S by 0·05 kg kg^?1 (P = 0·036), NFRV_N by 0·05 kg kg^?1 (P = 0·090) and NFRV_DM by 0·11 kg kg^?1 (P < 0·001). It was concluded that the main factor causing these decreases with HG, compared with LG applications, was wheel damage affecting subsequent N uptake and growth of the taller grass sward.     

结球甘蓝测土配方施肥同田对比研究

[目的]验证不同肥力水平下蔬菜结球甘蓝的最佳施肥量在实际应用中的效果,指导大面积生产。[方法]选取高肥力与中肥力地块2组,各设置无肥区、习惯施肥和配方施肥区3个处理,研究测土配方施肥对蔬菜结球甘蓝产量及经济效益的影响。[结果]高肥力地块配方施肥区与习惯施肥区相比,增产率达到了4.8%,与无肥区相比,增产率达到了22.4%;中肥力地块配方施肥区与习惯施肥区相比,增产率达到了4.3%,与无肥区相比,增产率达到了26.8%,增产效果显著,经济效益明显。[结论]在今后结球甘蓝生产中,应大量推广使用配方施肥技术,既提高产量又增加效益,同时提高肥料利用率,减少环境污染和肥料副成分的残留,对可持续农业发展意义深远。     

Suppressing weeds in direct-seeded lowland rainfed rice: Effect of cutting dates and timing of fertilizer application

Weeds cause substantive yield losses in rainfed rice, particularly direct-seeded rice (DSR). Two field experiments were conducted in 2005 in north-east Thailand to examine the effects of cutting date and timing of fertilizer application on suppressed weed, growth and yield of DSR. Treatments consisted of two fertilizer applications to the main plots (top-dressing at the date of cutting and 15 days after cutting; DAC) and four cutting dates of the sub-plots. Rice and weed cutting was performed at 30, 45, 60 and 75 days after seeding (DAS), compared with an untreated control. Cutting resulted in a higher growth rate and improved grain yield of rice compared to the untreated control. Weed cutting at 60 DAS resulted in the greatest leaf area index, which contributed to the maximum number of tiller as well as maximum plant dry mass when observed at 30 DAC. Lower densities and dry weights of weeds at 30 DAC were observed when cutting was done 60 DAS, resulting in a higher grain yield than the other cutting dates. Timing of fertilizer application had no significant effect on the density and dry weight of grasses and broad-leaved weeds, but did have a significant affected on, resulting in the lowest density of sedges at 45 DAC was observed with fertilizer applied at cutting date. Rice grain yield was higher with top-dressing of fertilizer at 15 DAC than with fertilizer applied at cutting date. The cutting treatments resulted in higher net incomes than the untreated control. These results indicate that rice and weed cutting at an appropriate growth stage is an alternative method to chemical weed control for DSR in rainfed riceland.     

甜菜碱的制备方法及应用

甜菜碱的制备方法有两种:一是从甜菜糖蜜中直接提取;二是采用人工合成,最常用的方法是用一氯乙酸与三甲胺进行人工合成。甜菜碱是一种季铵型生物碱,是一种高效甲基供体,能调节动物体内渗透压、促进脂肪代谢和蛋白质合成。甜菜碱及其衍生物在化工、印染、日化、医药、食品、饲料等领域都有广泛的用途。     

Effect of the insect growth regulator novaluron on diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), and its indigenous parasitoids

Research to evaluate effective and selective insecticides through periodic screening is needed to strengthen diamondback moth (DBM) (Plutella xylostella L.) management. The efficacy of the insect growth regulator novaluron on DBM and effects on the parasitoids Diadegma sp. (Hym.: Ichneumonidae), Apanteles sp. (Hym.: Braconidae) and Oomyzus sokolowskii Kurdjumov (Hym.: Eulophidae) were evaluated. Novaluron was compared with the microbial insecticide Bacillus thuringiensis (Bt) var. aizawai, the pyrethroid insecticide λ- cyhalothrin and the organophosphate insecticide profenofos. Two replicated experiments were conducted on head cabbage, Brassica oleracea var. capitata, planted in March and May 2007 at Wonji in the Central Rift Valley of Ethiopia. Infestation by DBM was less with novaluron and Bt compared with other treatments for both planting dates. Infestation with λ-cyhalothrin and profenofos was comparable with the untreated control. Yields were greatest with novaluron and were 80 and 32.5% (12.4 and 7.4 t ha⁻¹) greater than the untreated treatment for the first and second plantings, respectively. Diadegma sp. accounted for 91% of the parasitoid complex observed. Parasitism of DBM by Diadegma sp. ranged between 10 and 43% among treatments. Parasitism was less with λ-cyhalothrin and profenofos compared with other treatments. Owing to its efficacy against DBM and relative safety to its parasitoid, Diadegma sp., novaluron can be used in integrated DBM management for low elevation brassica production in the Central Rift Valley of Ethiopia.     

生根粉在大田作物上的应用效果

生根粉通过调控大田作物重要酶的活性,促进根的分裂,使不定根原基萌发,降低因移栽等栽培措施引起的根系损伤,缩短缓苗期,促进根系早生快发,促进其生长发育。大田作物生理生化变化是其新陈代谢的体现。实践表明,生根粉运用于花生、小麦、棉花、水稻等大田作物,通过改变其生理生化指标,有利于促进体内营养物质的形成;对烟株喷施生根粉能使其ATP含量、游离氨基酸总量、叶绿素含量等有明显增加,提高育苗成活率和增强抗性。适当喷施生根粉还有利于提高大田作物的产量和经济产值,对其内在质量的提升也有明显效果。