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1.
Morphology and morphometry of six biotypes(B,Q,Cv,ZHJ-1,ZHJ-2 and ZHJ-3) of Bemisia tabaci(Gennadius) from China on cotton plants were studied by using microscopes.Nymphal body sizes and characters were measured and observed,especially on the 4th instar(pupal case),including the vasiform orifice,operculum,lingula,length and thickness of anterior and posterior wax margins,width of thoracic tracheal combs.Adult characters of both sexes were investigated including the body size,compound eyes,antennal segments,vasiform orifice,hind tarsi and genitals.The results indicated that differences of some morphological characters or morphometrics were significant among the six biotypes of B.tabaci in China:(1) Pupal sizes of the exotic biotypes(B and Q) were significantly larger than the indigenous biotypes with the following order as B>Q>ZHJ-1>Cv>ZHJ-3>ZHJ-2;(2) for both male and female adults,sizes of all characters investigated in the invading biotypes(B and Q),especially B,were much larger than those of the indigenous ones.  相似文献   

2.
The fall armyworm(FAW), Spodoptera frugiperda, is a newly invasive, widespread agricultural pest in China. Understanding the suitability of the main field crops in Chinese agricultural system as host for this polyphagous herbivore is especially important for making control strategy. Here, after FAWs were fed three important oil-bearing crops(oilseed rape, soybean and sunflower) planted in China and resultant population parameters were compared using the age-stage, two-sex life table method, survival of larvae on soybean was significantly lower than that on oilseed rape and sunflower. Developmental duration of larvae on soybean was also the longest(23.3 days). The highest pupation rate was recorded on sunflower. The highest pupal mass(0.19 g) was attained on oilseed rape, significantly higher than on the other host plants; the lowest mass was on soybean(0.15 g). On soybean, oilseed rape and sunflower, respectively, the average generation period was 42.21, 39.10 and 40.44 d; the intrinsic rate of increase(r) was 0.0844, 0.1041 and 0.1134; the finite rate of increase(λ) was 1.0881, 1.1098 and 1.1202. While the most suitable host plant overall was sunflower, S. frugiperda completed development and increased its population on all three host plants. Thus, soybean, oilseed rape and sunflower were all suitable for FAW, and population monitoring and management of FAW in these crops should be increased.  相似文献   

3.
To study the mechanism of plant K use efficiency, both K high and low use efficiency cotton genotypes, 103 and 122, respectively, were selected from 86 cotton cultivars (Gossypium hirsutum L.). The research was conducted using pot experiment for planting cotton on without K (0.0 g kg-1 soil) and with K (0.4 g kg-1 soil) treatments in 2005. Experimental result showed that, with K deficiency stress, genotype 103 grew much better than genotype 122 except that its lower leaves showed the symptoms of K deficiency, whereas all the leaves of genotype 122 showed the symptoms of K deficiency. Root dry matter weights of treatments for genotype 103 with and without K application were 1.07 and 1.25 times of genotype 122. It indicated that the root system of genotype 103 was well developed and has better nutrition uptake capability than that of genotype 122. The result also showed that the cotton shoots of genotype 103 were 1.07 and 1.13 times over genotype 122 on treatments of with and without K application. It indicated that genotype 103 has stronger transport organs. In genotype 103, plants, dry matter, and potassium were mainly transported to cotton bolls. The boll dry weight of genotype 103 was 2.58 times in without K treatment and 1.90 times in with K treatment over genotype 122. The potassium accumulation in bolls of genotype 122 was only 49.3% of that in genotype 103. Potassium accumulation in the other organs of genotype 103 was relatively low compared with in bolls. This indicated that the distribution of K and organic matter in genotype 103 was more efficient than genotype 122. The main differences between high K efficiency cotton genotype 103 and low K efficiency genotype 122 lie in their potassium nutrition and organic matter using efficiency on uptake, transportation, accumulation, distribution, and utilization.  相似文献   

4.
Goosegrass is one of the worst agricultural weeds on a worldwide basis. Understanding of its interference impact in crop field will provide useful information for weed control programs. Field experiments were conducted during 2010–2012 to determine the influence of goosegrass density on cotton growth at the weed densities of 0, 0.125, 0.25, 0.5, 1, 2, and 4 plants m–1 of row. Seed cotton yield tended to decrease with the increase in weed density, and goosegrass at a density of 4 plants m–1 of row significantly reduced cotton yields by 20 to 27%. A density of 11.6–19.2 goosegrass plant m–1 of row would result in a 50% cotton yield loss from the maximum yield according to the hyperbolic decay regression model. Boll production was not affected in the early growing season. But boll numbers per plant were reduced about 25% at the density of 4 plants m–1 of row in the late growing season. Both cotton boll weight and seed numbers per boll were significantly reduced(8%) at 4 goosegrass plants m–1 of row. Cotton plant height, stem diameter and sympodial branch number were not affected as much as cotton yields by goosegrass competition. Seed index, lint percentage and lint fiber properties were unaffected by weed competition. Intraspecific competition resulted in density-dependent effects on weed biomass per plant, 142–387 g dry weight by harvest. Goosegrass biomass m–2 tended to increase with increasing weed density as indicated by a quadratic response. The adverse impact of goosegrass on cotton yield identified in this study has indicated the need of effective goosegrass management.  相似文献   

5.
The genus Adelphocoris(Hemiptera: Miridae) is a group of key insect pests in cotton fields in China that includes three dominant species: A. suturalis(Jakovlev), A. lineolatus(Goeze) and A. fasciaticollis(Reuter). Previous field surveys have found that adults of these Adelphocoris species usually move onto specific host plants when the plants enter the flowering stage. To determine the potential trade-offs for this host-plant preference behavior, the performance of these three Adelphocoris spp. on flowering and non-flowering cotton and alfalfa were compared in the laboratory. The results showed that Adelphocoris spp. had significantly higher nymphal developmental and survival rates, along with increased adult longevity and fecundity on flowering cotton and alfalfa than on non-flowering plants of either species. In addition, compared with cotton plants, alfalfa generally promoted better performance of these three Adelphocoris species, especially for A. lineolatus. Simple correlation analysis indicated that female adult longevity was positively correlated to male adult longevity and female fecundity, and female fecundity was positively correlated to nymphal development and survival rates. This study demonstrated a positive correlation between adult preference and offspring/adult performance for all three Adelphocoris species, with no evidence of any trade-offs for this preference for flowering host plants. These findings support the hypothesis that hemimetabolous insects such as mirid bugs have positive adult preference-adult/nymphal performance relationships, which is likely due to the similar feeding habits and nutritional requirements of adults and nymphs.  相似文献   

6.
To study the relations between DNA methylation and abiotic stress responses in cotton (Gossypium hirsutum L.),the methylation-sensitive amplified polymorphism (MSAP) method was used to investigate the differences in methylation level and the change of cytosine methylation patterns under salt (NaCl) stress in two different salt-tolerant cotton lines.The results showed that the number of the cytosine methylation of CCGG sites in high salt-tolerant cotton line was less than that in low salt-tolerant line.Under salt stress,extensive cytosine methylation alterations including hypermethylation and demethylation as well as the potential conversion of methylation types occurred in the salt-treated cotton line compared with the corresponding control.Interestingly,salt stress-induced demethylation loci that occurred in high salt- tolerant cotton line were greater than those in low salt-tolerant cotton line,however,salt stress-induced hypermethylation loci in the high salt-tolerant cotton line were less than those in low salttolerant cotton line.It suggested that the demethylation positively contributed to salt tolerance and the hypermethylation had negative effect on salt tolerance in cotton.  相似文献   

7.
Transgenic corn was modified to combat lepidopteran pests, herbicide and other deteriorate environmental factors. However, fewer studies concerned the effects of transgenic corn cultivation on the soil Collembola in black soil region in China. In Jilin black soil region, a six treatments study including three corn varieties (transgenic corn, control and local variety) and two sampling locations (in rizhosphere and in between plants) were deployed to study the effect of transgenic corn cultivation and sampling location on densities, species richness and community structure of Collembola. We found that root biomass was marginally decreased in transgenic corn and control variety when compared to local variety. Collembola significantly affected by sampling location treatments. Densities and species richness of collembolans significantly decreased in "between plants" than in "rizhosphere". Densities of Collembola were impacted by corn varieties. In the whole growing season, densities of Collembola significantly decreased in control than in local variety. Collembolans in transgenic variety only slightly decreased in "jointing stage" than local variety. Collembolans adversely affected in "between plants" when compared to "in rhizosphere" in "seeding stage" but not other stages. These variations of collembolans were in lines with the trend of corn root biomass. It is indicated that Collembola variations could be caused by food resources (root biomass) but not corn varieties (transgenic, control and local).  相似文献   

8.
The fitness of cotton aphid, Aphis gossypii Glover, on different host plants was studied. The results showed that the cotton aphid population in Nanjing formed host preference bio-types on cucumber and cotton. The aphids from cotton and cucumber could not inter-transplant successfully between the two host plants. The apterous and alate offspring of stem mother from hibiscus could not survive, reproduce and form population normally when they were transplanted to cucumber and water melon, but they could form normally when transplanted to cotton and muskmelon. There was no significant difference between the stylet length of cotton aphids from cucumber and cotton, so the stylet length was not the cause of the host preference. When the aphids originated on hibiscus were transplanted to cotton, water melon and muskmelon, the stylet could reach host phloem to absorb host plant‘s nutrients, but it couldn‘t when transplanted to cucumber. Cotton aphid can feed on muskmelon without secretion of water-soluble saliva. It could be concluded that the two host biotypes of cotton aphid came from different winter host plants.  相似文献   

9.
The study aims to clarify the differential gene expression between cotton hybrids and their parents in order to better understand the molecular basis of cotton heterosis. The research focused on cotton heterotic and lower heterotic hybrids and their parents during the four crucial stages, which were analyzed using a differential display technique. The results indicated that there were both quantitative and qualitative differences in gene expression amongst them. The quantitative differences include over- and under-expression of parental genes and the dominant expression of highly-expressed parental genes in hybrids. In contrast, the qualitative differences are the following: (i) Bands were observed in both parents but not in the F1 hybrid (BPnF1); (ii) bands occurred in either of the parents but not in the F1 hybrid (UPnF1); (iii) bands presented only in the F1 hybrid but not in either of the parents (UF1nP); and (iv) bands were detected in either of the parents and the F1 hybrid (UPF1). Overall, the major differences of gene expression occurred in the qualitative level and four related differential patterns were observed. Furthermore, the amount of differential patterns during the flowering stage was relatively higher than those of other stages. At this juncture, both the amount of hybrid-specific expression patterns at flowering stage and the silenced expression patterns at boll-forming stage in highly heterotic hybrids were found higher than those in the lower heterotic ones. It was concluded that significant differences of gene expression in leaves were present between cotton hybrid and its parents during the whole growing stages. Hence, these differences might be responsible for the observed cotton heterosis.  相似文献   

10.
The use of allelopathic plants is an alternative technique for controlling weeds in sustainable crop production. This experiment evaluated the allelopathic potential of Murraya paniculata (L.) against four weeds viz., Bidens pilosa L., Amarathus spinosus L., Echinochloa crusgalli (L.) Beauv. and Chloris barbata Sw.. In laboratory test, aqueous extracts from M. paniculata leaves at concentrations of 12.5, 25, 50 and 100 g/L were tested on germination and seedling growth of the weeds. The extracts showed inhibitory effect, varying with weed species and extract concentration. Increase in concentrations increased the degree of inhibition. Concentration at 50 g/L and 100 g/L, completely inhibited seed germination of C. barbara and A. spinosus. Pot experiments were done in a glasshouse, with dry leaf powder as mulch on the soil surface at levels of 2, 4 and 8 t/ha. Dry leaf powder reduced the emergence and growth of all tested weeds, varying with dose and species. Chloris barbara is the most sensitive to M paniculata leaf mulch while E. crus-galli is the most resistant. These results suggest that M. paniculata had the potential lbr weed control and might be the source of a natural herbicide.  相似文献   

11.
采集新疆南北棉区的棉花症状表现为黄斑型和落叶型的以及从茄与苍耳上分离得到的黄萎轮枝菌共6个菌株,进行了形态学及生物学特征特性的比较研究。结果表明,6菌株都无形态学上的显著差异,其生物学特征特性也基本雷同。6个菌株同在棉、红花、向日葵、茼麻、苍耳和辣椒上作交互接种,均表现为不侵染辣椒,但对其他的6种供试植物均持不同程度的致病力现象。以茄菌与苍耳菌对供试的6种植物的致病力都强,而寄生在棉花上的4个菌株除对其原寄主的致病力为中、强度外,对红花、向日葵、苍耳及苘麻的致病力也强,但对茄的致病力则弱,或无致病能力。本试验6个菌株均应被鉴定为大丽花轮枝菌(Verticillium dahliae Kleb.),但从其全部的表现形式看仍有较明显的生理分化现象。从棉花上的4个菌株表现的形式可以看出,南北疆棉黄萎病的黄斑型与落叶型分离物均同属于中、强度侵染的致病菌,在许多情况下,黄斑型菌株的致病力还往往强于落叶型菌株的致病力,从当前南北疆棉区的棉花黄萎病中表现有落叶型反应的病株,很难断定为系属强致病力变异菌株的症状反应。  相似文献   

12.
The Bemisia tabaci (Gennadius) cryptic species complex comprises important insect pests that cause devastating damage to agricultural crops worldwide. In China, the B. tabaci Mediterranean (MED) (or biotype Q) species is threatening agricultural production all over the country as resistance to commonly used insecticides has increased. This situation highlights the need for alternative pest control measures. Cyantraniliprole, a novel anthranilic diamide insecticide, has been widely employed to control Hemipteran pests. To monitor the levels of resistance to cyantraniliprole in B. tabaci field populations in China, bioassays were conducted for 18 field samples from nine provinces over two years. Compared with median lethal concentration (LC50) for the MED susceptible strain, all field samples had significantly higher resistance to cyantraniliprole. Furthermore, resistance factors (RFs) increased significantly in samples from Shanxi (from 5.62 in 2015 to 25.81 in 2016), Hunan (3.30 in 2015 to 20.97 in 2016) and Hubei (from 9.81 in 2015 to 23.91 in 2016) provinces. This study indicates a considerable decrease in the efficacy of cyantraniliprole against B. tabaci and establishes a baseline of susceptibility that could serve as a reference for future monitoring and management of B. tabaci resistance to cyantraniliprole.  相似文献   

13.
利用诱集寄主苘麻防治B型烟粉虱的研究   总被引:22,自引:0,他引:22  
【目的】 利用烟粉虱对寄主植物苘麻的嗜好趋性,研究棉花和大豆田的苘麻诱杀B型烟粉虱的技术体系。【方法】设计了不同播种期、种植方式和配套施药方法来研究苘麻对烟粉虱的诱集防治效果。【结果】在棉花和大豆的整个生长期间,苘麻对烟粉虱均有极显著的诱集作用,但不同播期苘麻的诱集效果差别明显。在棉花和大豆生长早期,烟粉虱最先在早播的苘麻上发生,诱集效果达85.2%;中播和晚播苘麻对棉花和大豆生长中、后期的烟粉虱诱集效果显著,分别达到93.3%和95.4%。苘麻植株在田间分散程度和诱集效果呈正相关,单棵插花种植苘麻的诱集效果分别是片状种植和条带种植苘麻的7倍和3倍。配套施药试验结果表明,苘麻喷洒25%阿克泰水分散粒剂、5%锐劲特悬浮剂、25%扑虱灵可湿性粉剂、10%高渗高效氯氰菊酯乳油和25%高渗辛硫磷乳油7 d 后对烟粉虱成虫和幼虫的防治效果分别为21.76%~97.57%和27.02%~74.77%,以阿克泰和锐劲特防治效果最佳。【结论】基于播种期、种植方式和配套合理的药剂防治的苘麻诱集方法对生态调控棉田和大豆田中的烟粉虱发挥了积极的作用。  相似文献   

14.
【目的】 研究豚草(Ambrosia artemisiifolia L.)和三裂叶豚草(Ambrosia trifida L.)浸提液对常用替代牧草高羊茅、早熟禾、黑麦草、披碱草,以及对苜蓿、葵花、玉米、小麦、甜菜种子萌发的影响;筛选对豚草和三裂叶豚草具有防控效果的替代植物以及最佳混种方式。【方法】 采用培养皿滤纸法,研究豚草和三裂叶豚草浸提液对供试种子萌发的影响。采用盆栽竞争试验,运用DeWit取代试验研究法,设置牧草和入侵杂草5种混种方式,混种比例分别为1∶1、1∶2、1∶3、2∶1、3∶1,研究黑麦草、披碱草和高羊茅与豚草和三裂叶豚草的竞争效应,分析3种牧草对豚草和三裂叶豚草的替代控制潜力。【结果】 随着豚草和三裂叶豚草的浸提液浓度的增加,4种常用替代牧草种子和新源县5种主要作物种子发芽率,发芽指数和化感效应指数均下降。5种混种密度下,黑麦草、高羊茅与三裂叶豚草混种比例为3∶1时,三裂叶豚草的竞争平衡指数分别为(-0.505 1±0.301 5)、(-0.757 6±0.265 88)均显著小于0(P<0.05);黑麦草、高羊茅与豚草混种比例为1:3时豚草竞争平衡指数分别为(-0.955 8±0.518 08)、(-2.049 7±0.178 55)均显著小于0(P<0.05)。【结论】 豚草和三裂叶豚草浸提液对供试种子萌发具有化感抑制作用;且浸提液浓度越大抑制作用越强,同时叶部化感抑制作用大于根部。三裂叶豚草对四种牧草种子萌发的化感抑制作用大于豚草。黑麦草和高羊茅可以作为豚草和三裂叶豚草的替代植物。黑麦草和高羊茅防治三裂叶豚草时建议播种比例为3∶1;防治豚草时建议播种比例为1∶3。豚草和三裂叶豚草发生密度较大时其化感抑制作用越强,影响牧草萌发生长,应适当加大替代牧草播种量。  相似文献   

15.
为进一步了解雄安新区及其周边地区烟粉虱的生物型及其种群发生为害动态,分别于2016和2017年对雄安新区及其周边5个县级辖区的烟粉虱的生物型(隐种)、种群动态和空间分布格局进行了调查研究。结果表明:目前该地区主要蔬菜作物上发生的烟粉虱均为Q型(MED隐种)烟粉虱;整个调查期间,均发现烟粉虱发生为害情况,不同寄主植物上烟粉虱种群动态不同,每年9月中下旬,烟粉虱在茄子和棉花上的种群密度都有不同程度的回升;绝大多数情况下,烟粉虱在寄主植物上属聚集分布。上述研究结果为烟粉虱的预测预报和防治策略的制定提供了理论依据。  相似文献   

16.
大麻对瓜列当和向日葵列当种子萌发诱导作用研究   总被引:3,自引:2,他引:1  
以宁夏回族自治区固原市当地种植的大麻为材料,采用盆栽试验探索大麻在不同生育期(苗期、快速生长期、开花期)的根际土、根、茎及叶的甲醇和水提取液对瓜列当和向日葵列当种子萌发的刺激效果。结果表明:根际土提取液刺激瓜列当种子的发芽率大于向日葵列当。大麻植株的甲醇和水提取液刺激瓜列当种子发芽率高低顺序为根茎叶,其中甲醇提取液刺激列当种子萌发率高于水提取液。根与茎的甲醇提取液刺激瓜列当和向日葵列当种子发芽率均显著相关(R2=0.833 6,P0.001和R2=0.544 4,P0.05)。植株的甲醇提取液对瓜列当种子的萌发诱导作用在快速生长期最强(45.2%),而向日葵列当种子的萌发诱导作用则在苗期最强(41.5%),水提取液对瓜列当及向日葵列当种子萌发诱导作用均在苗期表现为最强,发芽率分别为53.6%和23.7%。本研究结果表明,大麻在苗期和快速生长期可以作为列当的"捕获"作物,结论可为生物防除寄生杂草列当提供科学依据。  相似文献   

17.
Insects are poikilothermic animals, and temperature is one of the most important abiotic factors affecting their spread and distribution. For example, differences in thermal tolerance may underlie the significant differences in geographical distributions between the native AsiaII3 and invasive MED (Mediterranean) cryptic Bemisia tabaci species in China. Transient receptor potential (TRP) channels are key components of the insect temperature perception system and act as molecular thermometers since they can be activated by specific changes in temperature. In this study, we cloned and characterized the AsiaII3 BtTRP gene and revealed its functions in the response to thermal stress. The full-length cDNA of BtTRP was 3821 bp, with a 3501-bp open reading frame encoding a 132.05-kDa protein. Comparing the deduced amino acid sequences of AsiaII3 BtTRP and MED TRP revealed five amino acid differences. In situ hybridization indicated that BtTRP might be widely expressed throughout the AsiaII3 adult body. BtTRP mRNA expression reached the highest levels after exposure to mild thermal stimuli (12 and 35°C), showing that BtTRP expression can be induced by temperature stress. Furthermore, the thermal tolerance of AsiaII3 after BtTRP dsRNA feeding was significantly lower than that of the control. Taken together, the present study highlights the importance of TRP channels for B. tabaci thermal resistance, and allows us to infer that the differences in amino acids between AsiaII3 and MED might cause the differences in thermal tolerance of these two cryptic species. This study provides a new direction for investigating geographic distribution differences between invasive and native insects.  相似文献   

18.
An intelligent real-time microspraying weed control system was developed. The system distinguishes between weed and crop plants and a herbicide (glyphosate) is selectively applied to the detected weed plants. The vision system captures 40 RGB images per second, each covering 140 mm by 105 mm with an image resolution of 800 × 600 pixels. From the captured images the forward velocity is estimated and the spraycommands for the microsprayer are calculated. Crop and weed plants are identified in the image, and weed plants are sprayed. Performance of the microsprayer system was evaluated under laboratory conditions simulating field conditions. A combination of maize (Zea mays L.), oilseed rape (Brassica napus L.) and scentless mayweed (Matricaria inodora L.) plants, in growth stage BBCH10, was placed in pots, which were then treated by the microspray system. Maize simulated crop plants, while the other species simulated weeds. The experiment were conducted at a velocity of 0.5 m/s. Two weeks after spraying, the fraction of injured plants was determined visually. None of the crop plants were harmed while 94% of the oilseed rape and 37% of the scentless mayweed plants were significantly limited in their growth. Given the size and shape of the scentless mayweed plants and the microsprayer geometry it was calculated that the microsprayer could only hit 64% of the scentless mayweed plants. The system was able to effectively control weeds larger than 11 mm × 11 mm.  相似文献   

19.
田间系统调查结果表明,棚室番茄植株上主要害虫为烟粉虱和蚜虫;巴氏钝绥螨和胡瓜钝绥螨均对烟粉虱虫口密度具有一定的抑制作用,其控害持效期50 d左右。2种捕食螨、2个释放密度对烟粉虱的控害效果无显著性差异,但巴氏钝绥螨控害作用略强于胡瓜钝绥螨。烟粉虱种群时间生态位宽度值为捕食螨释放区大于空白对照区,化防区最低,其值仅为0.5818;表明化防区目标害虫虫口数量在时间系列上分布的不均匀性,种群波动幅度较大,有暴发成灾的可能;而生防区害虫种群变化较稳定,不易成灾。烟粉虱种群空间生态位宽度在各处理区间无显著差异。  相似文献   

20.
为了探明烟粉虱在不同寄主上的适合度,对烟粉虱在5种番茄品种上的选择性、发育历期及存活率等指标进行了比较.结果表明:烟粉虱在5个不同番茄品种上选择性差异具有统计学意义.其中,烟粉虱偏好在粉都53番茄品种上取食,对洛番9号、金粉101、越夏红有中等偏好性,对金鹏8号无明显偏好性.烟粉虱在5个番茄品种上的发育历期、存活率差异也具有统计学意义.烟粉虱在粉都53、洛番9号、金粉101、越夏红、金鹏8号上的发育历期依次延长,而在洛番9号上的烟粉虱存活率最高,在金粉101上的存活率最低.不同寄主对烟粉虱的适合度影响较大,在对烟粉虱的抗性上差异较为明显.  相似文献   

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