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1.
Selected commercial and technical grade pesticides were tested against the egg, preparasite and adult stages of Agamermis unka , a nematode parasite of the brown planthopper, Nilaparvata lugens . The commercial insecticide, diazinon (LC = 0.37 ppm), was most toxic to the 50 preparasites, followed by phenthoate (LC = 0.43 ppm), BPMC (LC = 0.44 ppm), IBP 50 50 (LC = 0.46 ppm), cartap hydrochloride (LC = 0.82 ppm) and buprofezin + isoprocarb 50 50 (LC = 1.11 ppm). The least toxic commercial pesticide tested was the fungicide, pencycuron 50 (LC = 2.19 ppm). Out of 12 technical grade insecticides tested, phenthoate, monocrotophos, 50 diazinon and carbofuran (LC = 0.37-0.46 ppm) were highly toxic to the preparasites, followed by 50 buprofezin, BPMC and fenitrothion (LC = 0.74-0.86 ppm). Fenthion, etofenprox, chlorpyrifos, 50 imidacloprid and MIPC (LC = 1.11-2.19 ppm) were the technical grade insecticides least toxic 50 to the preparasites. Most preparasites survived for up to 24 h at the low insecticide concentrations (0.63 and 0.31 ppm). Preparasites that were exposed to BPMC for 24 h at concentrations as high as 5.0 ppm and survived the treatments infected brown planthopper nymphs. Four selected insecticides-chlorpyrifos, BPMC, imidacloprid and carbofuran-had significant adverse effects on A. unka egg hatching. Eggs that were in the insecticide solution for 168 h fared poorly with imidacloprid having the best survival ( > 2% of the eggs hatching at 0.04 ppm). No eggs hatched from the other insecticide treatments. Three selected insecticides, BPMC, imidacloprid and chlorpyrifos, tested against adult A. unka showed that most adults survived the exposure to the insecticides between 0.31 and 2.5 ppm. At 5.0 ppm of BPMC or chlorpyrifos none of the adults survived, whereas with imidacloprid 70% of the adults survived. Egg deposition by the surviving adults was greatly reduced in those treated with the insecticides compared with those in the controls. Imidacloprid had some negative impact on the preparasites' ability to infect BPH nymphs, but it had the least detrimental effect of the insecticides tested on preparasite survival and on the eggs and adults of A. unka .  相似文献   

2.
Adults of the brown planthopper (BPH) and the whitebacked planthopper (WBPH) that migrated into Korea from China were not parasitized by the mermithid, Agamermis unka. BPH and WBPH collected from Korean rice fields were parasitized. Parasitism of BPH in the lst-3rd, 4th, and 5th instars, and adults was 31.5%, 61.5%, 66.4%, and 45.5%, respectively, whereas parasitism of the same stages of WBPH was 50%, 50%, 100% and 90.7%, respectively. Parasitism of BPH by A. unka significantly reduced the number of eggs. Only 4.2% of the parasitized females contained eggs, whereas 85.6% of unparasitized females had eggs. Tilling of rice fields significantly increased mermithid parasitism of BPH. Mermithids parasitized 39.3% of caged adults in the untilled field and 77.8% in the tilled field.  相似文献   

3.
安志芳  于居龙  彭娟  张超  刘向东 《昆虫学报》2014,57(11):1306-1314
【目的】为了明确光周期和遗传因子在稻飞虱翅型分化中的作用, 研究了3种稻飞虱(褐飞虱Nilaparvata lugens、白背飞虱Sogatella furcifera和灰飞虱Laodelphax striatellus)翅型纯系或近纯系在不同光照时数下的翅型分化比率。【方法】以经过5~45代连续翅型筛选后的褐飞虱、白背飞虱和灰飞虱的长翅型和短翅型纯系或近纯系为材料, 在室内分别测定了其在长光照(16和20 h)、短光照(4~12 h)和正常光照(14 h) 3类光周期条件下饲养后, 雌、雄成虫中长翅和短翅个体出现的比率及存活率。【结果】白背飞虱和灰飞虱的长翅型纯系M♂×M♀或短翅型纯系B♂×B♀在不同光周期下的翅型比率均无显著差异(P>0.05)。褐飞虱短翅型近纯系B♂×B♀的雌虫短翅率和成虫总短翅率在不同光周期下也无显著差异(P>0.05), 但雄虫短翅率在正常光照14 h和短光照4 h下显著高于长光照20 h下的(P<0.05)。当褐飞虱短翅型达到纯系后, 其后代翅型在6~16 h光照条件下无显著差异。褐飞虱长翅型近纯系M♂×M♀的后代虽有短翅个体出现, 但是雌虫和雄虫的各自短翅率在不同光周期下无显著差异(P>0.05), 仅总体短翅率在12 h光照条件下的显著高于16 h下的(P<0.05)。褐飞虱长、短翅型杂交筛选品系M♂×B♀的雌虫短翅率随光照时数的延长而升高; 灰飞虱杂交筛选品系M♂×B♀的短翅雄虫随光照时数的缩短而增多(P<0.05), 但当筛选代次达到45代时, 这种趋势不再显著。3种稻飞虱长翅型和短翅型纯系或近纯系若虫的存活率会稍低于长、短翅型杂交后代的存活率, 但长、短翅型品系的存活率在6~16 h光照条件下差异不显著(P>0.05)。【结论】稻飞虱翅型分化对光周期的反应受飞虱本身遗传背景的影响, 翅型纯系后代个体的翅型分化对光周期变化不敏感。  相似文献   

4.
The mermithid Agamermis unka, a parasite of the brown planthopper (BPH), was found in many rice paddies in Gyeongnam Province, Korea. Nematode parasitism of adult BPH varied from year to year, reaching as high as 50% in paddies not treated with an insecticide. Parasitism was lower in insecticide-treated paddies. Generally, mermithid parasitism was higher in BPH adults collected from the lower part (19%) compared with adults collected from the upper part (8%) of the rice plant and in brachypterous (57%) compared with macropterous forms (8%). No difference in parasitism between first (54%) and second (57%) generation was observed.  相似文献   

5.
《Journal of Asia》2019,22(4):1180-1186
The brown planthopper Nilaparvata lugens negatively affects rice yield by sucking nutrients from the rice stem and spreading viruses. In this study, the effects of sublethal concentrations of abamectin on development, fecundity, and wing morphs of N. lugens were investigated. Treatment with sublethal concentrations of abamectin showed no significant effects on the developmental period of F0 nymphs. Although LC10 and LC25 treatments resulted in 10% and 25% mortality, the LC25 treatment significantly prolonged the lifespan of macropterous and brachypterous females. Abamectin-treated brachypterous females showed significantly lower fecundity than control females. Furthermore, abamectin treatment showed no significant effects on the developmental period of F1 nymphs. However, LC25 treatment significantly inhibited the fecundity of brachypterous F1 females and significantly reduced the proportion of macropterous F1 females and brachypterous F1 males. LC25 treatment showed no significant effects on the fecundity of macropterous F1 females. Considering the proportion of macropterous and brachypterous F1 females, the relative fitness of the macropterous F1 nymphs in the control, LC10, and LC25 treatment groups was 1, 1.02, and 0.84, respectively, and that of brachypterous F1 nymphs was 1, 0.79, and 0.93, respectively. Sublethal concentrations of abamectin inhibited N. lugens emergence. The present findings indicate the potential of abamectin for N. lugens field control.  相似文献   

6.
The effects of elevated CO2 (750 vs. 375μl/l) on population abundances and metabolism enzyme of AChE and protective enzymes of SOD, POD and CAT in brown planthoppers (BPH) Nilaparvata lugens, and on size and abundances of yeast‐like endosymbiotes (YLES) were studied as BPH fed Bacillus thuringiensis (Bt) rice expressing pure Cry1Ab after successively two generations in open‐top chambers. The results indicated that: (1) Brachypterous and macropterous subpopulations and total population increased with elevated CO2. Significant increases were found as BPH fed non‐transgenic rice while only significant increase as macropterous‐BPH fed Bt rice. (2) The responses of brachypterous and macropterous‐BPH to Bt rice were different. Brachypterous‐subpopulation significantly decreased (13.6%) while macropterous ones significantly increased (43.8%) as fed Bt rice relative to non‐transgenic rice at elevated CO2. (3) Elevated CO2 only significantly inhibited AChE activity as brachypterous‐BPH fed non‐transgenic rice. Significant increases in POD and SOD, and significant decrease in CAT were found as brachypterous‐BPH fed Bt rice, while significant increases in CAT and significant decrease in POD were also observed as fed non‐transgenic rice in elevated CO2 relative to ambient CO2. (4) Bt rice significantly inhibited POD and SOD activity at ambient CO2, while only significantly enhanced SOD activity at elevated CO2. (5) Elevated CO2 significantly decreased YLES per mg/head of brachypterous‐BPH females while only significantly decreased YLES per mg/head as brachypterous‐BPH males fed Bt rice. And there were significant differences in YLES width or length between females and males. Elevated CO2 can markedly affect the symbiosis relationship between YLES and BPH through the bottom‐up forcing on BPH physiological metabolism. And the damage inflicted by BPH on rice, irrespective of the presence of insecticidal genes, is predicted to be higher at elevated CO2. Furthermore, transgenic Bt rice can also exacerbate emigrating‐macropterous‐BPH occurring especially at elevated CO2.  相似文献   

7.
Transcriptome analysis of the brown planthopper Nilaparvata lugens   总被引:5,自引:0,他引:5  
Xue J  Bao YY  Li BL  Cheng YB  Peng ZY  Liu H  Xu HJ  Zhu ZR  Lou YG  Cheng JA  Zhang CX 《PloS one》2010,5(12):e14233
  相似文献   

8.
通过高温处理及交配产卵实验,探讨了高温对稻褐飞虱Nilaparvata lugens (Stal)发育与生殖的影响。研究了不同高温条件对褐飞虱若虫发育历期、产卵量、产卵前期、寿命等生物学特性的影响。34℃以上高温导致褐飞虱若虫发育历期延长。高温处理4龄若虫使羽化后的雌成虫产卵量减少。高温处理不同日龄雌成虫也致使其产卵量减少,其中以1日龄短翅型、3日龄长翅型的产卵量影响最大。高温处理后褐飞虱寿命缩短。高温恒温处理,对短翅型雌成虫的产卵前期影响不大,但能延长长翅型雌成虫的产卵前期;而高温变温处理致使短、长翅型雌成虫的产卵前期均延长。高温变温对褐飞虱生殖的影响程度大于高温恒温。高温处理组雌、雄成虫与对照组相应的成虫交配试验表明,高温对雌性的影响大于雄性。实验初步确定34℃为对褐飞虱发育与生殖产生影响的临界温度。  相似文献   

9.
褐飞虱Nilaparvata lugens(Stal)属迁飞性水稻害虫,其成虫有短翅和长翅两种翅型。 褐飞虱迁入雌虫均未经过交配,其短翅型由一对显性等位基因控制。翅型分化同时受到遗传和内分泌系统的协调控制,外界条件如密度和寄主等因子通过内分泌系统来影响翅型的分化。褐飞虱翅型分化的敏感龄期雌虫为1~3龄,而雄虫为1-5龄;不同若虫蜜度处理对褐飞虱成虫的前翅形成有一定的影响。分蘖期水稻饲养的褐飞虱短翅型比例明显高于孕穗期水稻饲养的褐飞虱。不同密度下各生物型间的翅型分化差异不显著。迁入地的浙江各种群属温带型,其雌虫短翅率低且与密度呈显著负相关;菲律宾热带种群雌虫在不同密度下均为短翅型,而雄虫的短翅率随密度增加而上升。广西种群接近热带型,其雌虫短翅率高但不随密度而变化。试验各种群的雄虫在中等密度甚至高密度时其短翅率出现最高。  相似文献   

10.
A male fitness advantage to wing reduction was investigated for the oriental chinch bug, Cavelerius saccharivorus, which is wing dimorphic. Field surveys for the frequency of matings between wing morphs showed that the mating probability was much higher in brachypterous males than in macropterous males in the early breeding season. Brachypterous males copulated with not only brachypterous females but also macropterous females in this season. This led to a considerable rate (30%) of insemination of macropterous females just before emigration even in the early breeding season. A rearing experiment for the pre-reproductive period of females revealed that females mated with brachypterous males copulated and oviposited earlier than females mated with macropterous males. These results indicate that there is a fitness advantage to wing reduction in the males of C. saccharivorus in terms of the earlier sexual maturation.  相似文献   

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