Natural control of the cereal cyst nematode, Heterodera avenae Woll., by soil fungi at three sites

Populations (eggs/g dried soil) of the cereal cyst nematode Heterodera avenae Woll. failed to increase at two sites on susceptible spring barley but increased slightly at another on spring oats. Nematode multiplication was not related to the numbers of females produced on roots in summer; fewer female nematodes were produced where populations increased than where they declined. The failure of the nematode to multiply was due to few (less than 40%) of the females forming cysts containing eggs, a reduction in fecundity and an increase in the number of encysted eggs containing fungi. Verticillium chlamydosporium was the main fungus causing the decline in nematode numbers. Nematophthora gynophila was present at all sites but was most active at Woburn where irrigation was used to keep soils moist. V. chlamydosporium was the main parasite of encysted eggs at all sites but soil-borne saprophytic fungi were also isolated. These fungi were not found in many eggs and were considered to be only weak parasites. Differences in resting fungal spore densities in soil were not always related to differences in rates of parasitism. The activity of N. gynophila is affected by soil moisture and density of females as well as the density of spores in soil. The production of chlamydospores by V. chlamydosporium may also depend on the isolate of fungus present: some isolates produce no such spores on artificial media or, possibly, in soil. This work has shown that V. chlamydosporium and N. gynophila can reduce cereal cyst nematode populations under susceptible cereals but it is difficult to predict at present if they will give an effective control in a given soil or season.     

缓释肥作出嫁肥对机插水稻秧苗生长发育的影响

在水稻生产上为了达到培育壮秧的目的,通过开展大田试验,采用缓释肥作出嫁肥进行研究。在水稻移栽前3 d人工撒施25 kg/667 m²缓释肥作出嫁肥,以常规施肥作对照,在水稻移栽后定期取样测定秧苗素质及在分蘖期调查水稻茎蘖动态,并综合评价缓释肥作出嫁肥对秧苗生长发育的影响。结果表明:与常规施肥相比,施用缓释肥作出嫁肥后,在14、21、28 d时,水稻秧苗的株高分别提高6.26%、5.38%、3.38%,地上部干质量分别提高35.29%、3.92%、4.59%,地下部干质量分别提高30.00%、30.43%、8.70%,但对秧苗的茎基宽、发根数及根冠比影响不大;在水稻茎蘖数方面,施用缓释肥处理较常规处理在7月1日、7月8日、7月15日、7月22日、7月29日分别高出12.97%、7.68%、12.08%、40.24%、16.59%。综上所述,施用缓释肥作出嫁肥,能够提高水稻秧苗的株高及干物质量,对茎基宽及发根数影响不大,在生长中期能够增强水稻的分蘖能力,提高分蘖期水稻的茎蘖数。使用该种缓释肥作出嫁肥后,能够通过提高秧苗株高、干物质量及分蘖数来达到壮秧的效果。     

寒地水稻插秧前寄秧应用效果探讨

为探讨插前寄秧措施对水稻秧苗素质、产量的影响,黑龙江北大荒农业股份有限公司2020年在16个分公司的试验田开展了水稻插前寄秧试验。结果表明,插前进行寄秧有利于缓苗、增加根量、促进早生分蘖,对产量形成有利;寄秧处理还能减少插后本田空穴少,减少了本田补苗用工量。其中,寄秧4 d的处理效果最好,产量比对照（现起现插）增产7.5 kg/667 m²,净增效益48.0元/667 m²。     

Induction of resistance to root-knot nematodes by SAR elicitors in tomato

Different concentrations of the systemic acquired resistance (SAR) elicitors, salicylic acid (SA), methyl-salicylic acid (MetSA), acibenzolar-S-methyl (ASM) and 2,6-dicholoroisonicotinic acid (INA), were provided to tomato seedlings as root-dip or soil-drench one day before inoculation with the root-knot nematode, Meloidogyne incognita. Nematode infestation was evaluated by counting egg masses/plant (EM), eggs/plant (Pf), and sedentary forms/plant (SF) in treated and untreated plants seven weeks after inoculation. An index of plant fitness (PF) was also calculated to assess the costs of chemically-induced resistance and the possible phytotoxicity of the treatments. SA and ASM were found to be effective elicitors of resistance when applied at suitable concentrations and method of application. Soil-drench with SA and root-dip in ASM were the most effective treatments as they markedly reduced both nematode reproduction (less than 50% that of untreated plants) and infestation (50–70% EM reduction). MetSA was less effective than SA in eliciting resistance because of its negative effects on plant fitness when it was provided as soil-drench. INA did not reduce nematode infestation at any of the non-phytotoxic rates. The reduction of nematode infestation and reproduction by SA applied as soil-drench was potentiated when the soil was enriched with humic acids. Soil-drenching with SA and MetSA were the only treatments that caused a long-lasting induction of plant defences as they inhibited the infestation by the second generation of the nematode.     

Screening of Pochonia chlamydosporia Brazilian isolates as biocontrol agents of Meloidogyne javanica

Pochonia species can occur in many Meloidogyne-infested soils throughout the world. The objective of this work was to isolate Pochonia species from different Meloidogyne-infested soil locations in Brazil and to screen for potential isolates effective in controlling Meloidogyne javanica under glasshouse conditions. A total of 29 isolates were identified as Pochonia chlamydosporia. Among them, 65.52% were identified as P. chlamydosporia var. chlamydosporia and 34.48% as P. chlamydosporia var. catenulata. For the glasshouse experiments, fungal chlamydospores were incorporated into the soil (5000 g soil⁻¹) and one tomato seedling was transplanted in 300 mL pot. After one week, each plant was inoculated with 1000 eggs of M. javanica. The isolates 1, 2, 3, 4, 9, 10, 21, 24, 28 (from Brazil) and 64 (from Spain) were the most efficient in reducing the number of eggs of the nematode. These isolates were re-evaluated in another glasshouse experiment, this time the number of eggs was increased (3000), inoculating both eggs and chlamydospores at the same time. After one week of inoculation, a tomato seedling was transplanted in each pot. In this experiment, isolates 64 and 10 were the most efficient in reducing the number of eggs by 72% and 60%, respectively.     

苏北地区稻麦秸秆持续全量还田下机插秧苗促早发技术

针对稻麦秸秆持续全量还田时土壤中秸秆总量和腐解强度显著提高,机插稻返青活棵时间普遍延长,甚至僵苗死苗严重、穗数难足、穗型较小等共性技术难题,淮安市农业技术推广中心提出了苏北地区稻麦秸秆持续全量还田下机插秧苗大田促早发技术,主要措施包括:培育适龄机插壮秧;控减底施化肥;适度减小耕整深度;足丛小株浅栽;无水层活棵、化除、施肥;早施分蘖肥,重施穗肥;全程湿润灌溉。     

Amendment of soil with African marigold and sunn hemp for management of Meloidogyne incognita in selected legumes

Field experiments were conducted in 2008 and 2009 in the tropical rainforest zone of Nigeria to investigate the effects of amendment of soil with seedlings of African marigold (Tagetes erecta) and sunn hemp (Crotalaria juncea) incorporated singly in plots on Meloidogyne incognita and yield of cowpea and soybean. The experimental field, which was naturally free of plant-parasitic nematodes, was inoculated with chopped roots of M. incognita race 2-infected Celosia argentea roots and planted to tomato to increase M. incognita population at the site.Eight week-old marigold seedlings were incorporated in cowpea or soybean field and eight week-old sunn hemp seedlings were also incorporated in cowpea or soybean field. At the ends of the experiments, M. incognita population densities were significantly higher in control plots than those of the plots amended with marigold or sunn hemp with correspondingly higher grain yield in the amended plots in both cowpea and soybean fields in both years. A significantly higher population of the nematode and consequently, lower yield was associated with cultivar Ife Brown than cultivar Ife Bimpe of cowpea for each treatment whereas in soybean cultivars, the pattern was not definite. Also twelve seedlings of marigold or sunn hemp per plot incorporated into the soil produced significantly higher grain yield in cultivar Ife Brown of cowpea and cultivar TGX 1440 of soybean compared to six seedlings per plot. The results of this study suggest that incorporating marigold or sunn hemp in M. incognita-infected cowpea or soybean field has potentials to suppress M. incognita population and reduce nematode damage on yield of the associated leguminous crops.     

Efficacy of Bacillus subtilis MBI 600 Against Sheath Blight Caused by Rhizoctonia solani and on Growth and Yield of Rice

Rice sheath blight disease(ShB),caused by Rhizoctonia solani,gives rise to significant grain yield losses.The present study evaluated the efficacy of Integral?,the commercial liquid formulation of Bacillus subtilis strain MBI 600,against rice ShB and for plant growth promotion.In greenhouse studies,four log concentrations of Integral(from 2.2×106 to 2.2×109 cfu/mL) were used as seed treatment(ST).After 25 d,seedlings were dipped(SD) into Integral prior to transplanting.At 30 d after transplanting(DAT),leaf sheaths were inoculated with immature sclerotia of the pathogen.At 45 DAT,a foliar spray(FS) with Integral was applied to some treatments.The fungicide control was 50% carbendazim at 1.0 g/L,and a nontreated control was also included.Overall,there were 10 treatments,each with five replications.ShB severity was rated at 52 DAT,and seedling height and number of tillers per plant were rated at 60 DAT.In 2009,two field trials evaluated Integral at 2.2×108 and 2.2×109 cfu/mL.Integral was applied as ST,and seedlings were produced in a nursery bed.After 32 d,seedlings were treated with Integral as SD and transplanted into 10 m2 blocks.Foliar sprays were given at 45 and 60 DAT.There were seven treatments,each with eight replications arranged as a factorial randomized complete block design.At 20 DAT,the plots were broadcast inoculated with R.solani produced on rice grains.Seedling height before transplanting,ShB severity at 90 DAT,and grain yield at harvest were recorded.Integral at 2.2×109 cfu/mL provided significant increase of seedling heights over other treatments under greenhouse conditions.The Integral treatments of ST + SD + FS at 2.2×109 cfu/mL significantly suppressed ShB over other treatments.In field studies,Integral provided significant increase of seedling height in nursery,and number of tillers per plant,compared with the control.ShB severity was significantly suppressed with higher concentrations of Integral compared to lower concentrations.Grain yield were the highest at an Integral concentration of 2.2×109 cfu/mL.Overall,Integral significantly reduced ShB severity,enhanced seedling growth,number of tillers per plant and grain yield as ST + SD + FS at the concentration of 2.2×109 cfu/mL under the conditions evaluated.     

黑龙江省大豆胞囊线虫种群分布和卵密度研究

对采自黑龙江省35个市县112份大豆田土样,采用蔗糖梯度离心法,研究了大豆胞囊线虫种群分布和种群密度.结果表明:从黑龙江省采集的所有大豆根围土样都检测到了大豆胞囊线虫,各地胞囊线虫的种群密度不同,每100 g干土中的虫卵量差别大,100 g干土中,嫩江县的大豆胞囊线虫卵量多达30 583个,最少的是抚远县,100 g干...     

Studies on the population dynamics and fungal parasitism of Heterodera schachtii in soil from a sugar-beet monoculture

A soil in which sugar beet had been monocultured for several years was treated with the fungicide captafol to investigate the effect of controlling nematophagous fungi on populations of Heterodera schachtii in the field and in pots. In the field trial, nematode populations failed to increase on sugar beet in the first 2 years in untreated soil, only increasing (×3·9) in the third. However, in captafol-treated soil, populations increased in all three years (x 3·0, x1 · 7 and x 6 · 5). In the pot experiment using the same soil and equivalent rates of captafol, greater multiplication occurred in captafol-treated pots. This was caused by an increase in lateral root weight which provided more invasion and feeding sites for the nematode, and by a reduction in fungal parasitism of female nematodes. Most of the natural control in the untreated soil operated on the second generation of the nematode. Cylindrocarpon destructans was the fungus isolated most frequently from infected females; Verticillium chlamydosporium and Fusarium spp. were also identified, but half of all isolates were diverse unidentified fungi. Fungal pathogens in beet monoculture did not cause H. schachtii populations to fall below the damage threshold, but might usefully be integrated with other measures, such as nematicides, to limit nematode increase.     

两种明尼苏达被毛孢对大豆胞囊线虫及大豆生长的影响

通过不同处理的接种试验研究了2种明尼苏达被毛孢对大豆胞囊线虫种群分布和大豆生长发育的影响.结果表明:接种35 d后,与空白对照相比,接种明尼苏达被毛孢1-10和HLJ07-21-3后大豆植株鲜重分别增加了30.98%和27.66%.明尼苏达被毛孢显著降低了(P<0.05)线虫卵、根部雌虫和土壤中胞囊的数量.与对照相比,...     

Evaluation ofSolarium fendleri as a source of resistance toMeloidogyne chitwoodi

Twelve accessions ofSolarium fendleri collected in the United States and Mexico were inoculated with 5,000 eggs of host-races 1 and 2 ofMeloidogyne chitwoodi, Columbia root-knot nematode. The test seedlings that were derived from plant introduction true seed lots were maintained for 55 days before harvest and egg count. The results revealed that two accessions, PI 275162 and PI 275165, were non-hosts (final egg count/initial egg inoculation < 0.1) forM. chitwoodi race 1. The results were uniformly confirmed in the second experiment. No resistance was found to race 2. The tetraploidS. fendleri accessions were crossed to a nematode-susceptible cultivated diploid potato clone from aS. phurejastenotomum population. The triploid hybrids expressed resistance to race 1 at the non-host level. After somatic doubling, the resulting hexaploids also expressed non-host-level resistance to race 1. The two resistant accessions had been collected in southeastern Arizona, one each from the Huachuca and Chiricahua Mountains. Each range is an isolated island of high-elevation mesic flora surrounded by typical lowerelevation Sonora-type desert habitat. These accessions are the only known sources of resistance toM. chitwoodi from wildSolanum species in the USA.     

The Effect of Alfalfa Residue Incorporation on Soil Bacterial Communities and the Quantity of <Emphasis Type="Italic">Verticillium dahliae</Emphasis> Microsclerotia in Potato Fields in the Columbia Basin of Washington State,USA

Verticillium wilt, caused by the soil-borne fungus Verticillium dahliae, is one of the most important diseases of potato in North America. Soil incorporation of alfalfa residues prior to planting potato could be a nonchemical Verticillium wilt management tactic by reducing the number of viable microsclerotia in field soil. Verticillium dahliae microsclerotia were quantified in field soils where organic material from alfalfa was incorporated, and numbers of microsclerotia were compared to fields where alfalfa residue was not incorporated. In addition, bacterial metagenomics was utilized to characterize soils where organic material from alfalfa was or was not incorporated to determine if alfalfa residue incorporation facilitates the formation of soils that suppress or kill V. dahliae microsclerotia. The number of V. dahliae microsclerotia in soil was greater (P = 0.0003) in fields where crop residue was incorporated than fields without incorporation when chloropicrin was used as a fumigant. Conversely, the number of V. dahliae microsclerotia observed in potato plants did not differ (P = 0.4020) between fields where residues were or were not incorporated if chloropicrin was used. Alfalfa residue incorporation did not significantly alter the soil bacterial metagenome compared to fields not subject to residue incorporation in both years of study. Despite these conclusions, the method can be employed to analyze the effect of grower practices with the intent of linking a field practice to increasing soil bacterial diversity and decreasing Verticillium wilt severity on potato.     

苏北地区粳稻生产中化学品投入普遍过量的原因及减投方案

通过调查发现,苏北地区粳稻生产中普遍存在化学品过量施用的现象,分析了其原因并提出了针对性减肥减药技术方案。方案主要包括：⑴选用适宜品种;⑵培育长秧龄壮秧、普施“出嫁药肥”;⑶麦秸全量还田;⑷浅耕地且防基肥渗漏;⑸抢早扩行移栽;⑹通气式灌溉、高质量搁田;⑺分蘖肥减量增效、施足穗肥;⑻综合防控。采用此减投技术,在化学品投入下降28%~42%的情况下,还能保障苏北地区粳稻成穗量充足、群体质量优良、病虫草害得到有效防控,进而实现“化投大降、产量不减、防效不降、安全高质”。     

Effect of different host plants on the fitness of diamond-back moth, Plutella xylostella (Lepidoptera: Plutellidae)

The diamond-back moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae) is a destructive cosmopolitan pest of cruciferous crops. The pest is present wherever its host plants exist and is considered to be one of the most widely distributed of all the Lepidoptera. We investigated the effect of various host plants on the fitness of P. xylostella and tested the hypothesis by studying development time, growth, fecundity and survival on cabbage (Brassica oleracea capitata), cauliflower (Brassica oleracea botrytis), radish (Raphanus sativus), turnip (Brassica rapa), mustard (Brassica compestris) and canola (Brassica napus var. canola). The developmental time from eggs to adult eclosion was the shortest (10 days) on canola and the longest (13 days) on turnip. Fecundity was greatest on canola (350) followed by cauliflower (268 eggs) by females eclosed from the pupae reared on canola and cauliflower, respectively, while the minimum numbers of eggs (184) were observed on cabbage. The number of eggs hatched was the highest (80%) when larvae fed on cauliflower. Survival to the adult stage was the highest (94%) on mustard followed by cauliflower and lowest (64%) on turnip. The net replacement rate was lowest for populations reared on cabbage (32.3), which was also reflected by the lowest intrinsic rate of population increase (0.20). The correlation between the intrinsic rate of population increase (r_m) and the mean relative growth rate was significant (t = 20.02 d.f. = 4, P < 0.05). Canola and mustard proved to be the most suitable hosts for P. xylostella because of shorter developmental period, higher percentage of survival and higher number of eggs. The data point to the role of host plants in increasing local P. xylostella populations.     

岳优9113作烟后稻机械插秧高产栽培技术

机械插秧具有效率高、降低生产成本、减轻劳动强度,便于合理密植、提高基本苗,适合带土、带药、带肥移栽,促使禾苗早生快发,促进水稻增产增收等优点,近年来得到迅速推广。试验以岳优9113为例,从播种育秧—机械插秧—田间管理各环节,阐述烟后稻机插高产栽培技术。     

Row fumigation with Vorlex for control of a meadow nematode (Pratlylenchus penetrans) in potatoes

Row fumigation with Vorlex at 3 and 7 gallons per acre was applied for meadow nematode (Pratylenchus penetrans) control in potatoes. The material was applied 3 weeks before planting using one chisel per row at a depth of 8″, and ridged. The treatments resulted in a reduction in population ofP. penetrans in the soil and in the potato roots. On a soil with a relatively high population of meadow nematodes, row application of Vorlex at 3 and 7 gal per acre resulted in a yield increase of 10 and 14% respectively, and a lower incidence of tubers with vascular discoloration. By early October as many nematodes were present in treated rows as in untreated rows. Row fumigation is of value for only one potato crop.     

橡胶树桩种植前假植方法研究

将挖取的实生苗树桩和热研7-33-97芽接桩分别假植在砂床上和泥土床上,10 d、20 d后再种植,与当天挖取的橡胶苗树桩进行种植对比试验。结果表明：种植后30 d,在砂床上假植20 d的实生苗树桩和热研7-33-97芽接桩的出芽数、株高明显高于其他各处理。说明将挖取的橡胶苗进行假植后再种植,与当天挖苗当天种植相比,不但没有降低成活率,还可提前出芽。     

Resistance of Selected Potato Genotypes to the Potato Psyllid (Hemiptera: Triozidae)

The characterization of resistance of selected potato, Solanum tuberosum L., breeding clones to the potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae) was investigated. Antixenosis was assessed in choice tests in which a single plant of each genotype was placed inside a rearing cage, where 60 female psyllid adults were released and the number of adults and eggs on each genotype was counted 24 h later. Antibiosis was evaluated in no-choice tests in which adults (five males and five females) were confined in a cage fixed to the upper side of leaves. After 4 h of exposure, adults were removed and the number of eggs counted. The developmental time and survival of offspring were recorded until all insects became adults. All the resistant genotypes showed strong antibiotic effects to B. cockerelli. These results show promise for incorporation into an IPM program against B. cockerelli.     

Varietal Differences in Biomass Production of Rice Early After Transplanting at Low Temperatures

Abstract

Low temperature decreases biomass production and yield in rice through a number of physiological and morphological changes. We evaluated biomass production in 22 high-yielding genotypes and four commercial japonica cultivars early after transplanting under field conditions for 2 years. The seedlings were transplanted on 30 April or 1 May (early transplanting, ET) and 4 weeks later (late transplanting, LT). The mean air temperature during the 18 days after transplanting in ET was about 4ºC lower than that in LT in both years. The seedling length was greater in high-yielding japonica varieties than in indica genotypes, whereas the seedling character index (SCI), which is the product of plant age in leaf number and the ratio of the seedling weight to its length, was the highest in the indica genotypes. Varietal differences in biomass production were greater in ET than in LT in all rice genotypes. The biomass at 18 days after transplanting was largest in the japonica high-yielding varieties Kusayutaka and Beko-aoba in both ET and LT. The biomass production of the indica genotypes was found to decrease severely after transplanting at low temperatures although the indica genotypes with high SCIs showed faster leaf emergence than the high-yielding japonica varieties. There was a strong positive correlation between the varietal differences in biomass production and shoot length at 18 days after transplanting in ET in both years. Our study suggests that superior shoot elongation in the high-yielding japonica varieties with large biomass allocation to the stems may be advantageous in maintaining biomass productivity at low temperatures.