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1.
Mitochondrial 16S ( approximately 550 bp) and cytochrome oxidase I (COI) ( approximately 700 bp) sequences were utilized as markers to reconstruct a phylogeography for representative populations or biotypes of Bemisia tabaci. 16S sequences exhibited less divergence than COI sequences. Of the 429 characters examined for COI sequences, 185 sites were invariant, 244 were variable and 108 were informative. COI sequence identities yielded distances ranging from less than 1% to greater than 17%. Whitefly 16S sequences of 456 characters were analysed which consisted of 298 invariant sites, 158 variable sites and 53 informative sites. Phylogenetic analyses conducted by maximum parsimony, maximum-likelihood and neighbour-joining methods yielded almost identical phylogenetic reconstructions of trees that separated whiteflies based on geographical origin. The 16S and COI sequence data indicate that the B-biotype originated in the Old World (Europe, Asia and Africa) and is most closely related to B-like variants from Israel and Yemen, with the next closest relative being a biotype from Sudan. These data confirm the biochemical, genetic and behavioural polymorphisms described previously for B. tabaci. The consideration of all global variants of B. tabaci as a highly cryptic group of sibling species is argued.  相似文献
2.
Host suitability of two biotypes of Bemisia tabaci on some common weeds   总被引:8,自引:0,他引:8  
Significant differences in some reproductive parameters of the B and Q biotypes of Bemisia tabaci (Gennadius) with regard to four species of winter weeds were determined in a no-choice assay. The highest fecundity (eggs) and fertility (pupae and adults) were obtained with Malva parviflora L. as host, followed by Capsella bursa-pastoris L., Brassica kaber (DC) and Lactuca serriola L. The percentage of adult emergence (from egg to adult) was significantly higher (P < 0.001) with M. parviflora, C. bursa-pastoris and B. kaber than with L. serriola. Except on L. serriola, the mean values of the reproductive parameters for the Q-biotype were significantly (P < 0.05) greater than those for the B-biotype. On the other hand, in choice experiments with summer weeds, both B- and Q-biotypes preferred Datura stramonium L. and Solanum nigrum L. to Amaranthus retroflexus L., Chenopodium album L. and Echinochloa crus-galli L. Significantly more males and females, and more pupae and empty pupal cases per plant were found on D. stramonium than on S. nigrum. Adult abundance on A. retroflexus, C. album and E. crus-galli plants was very low. At a constant temperature of 26 ± 1°C, the Q-biotype developed significantly faster than the B-biotype on S. nigrum and D. stramonium. Both biotypes required, for this development, significantly more days on D. stramonium than on S. nigrum. These results suggest that it is important to suppress the growth of M. parviflora, C. bursa-pastoris, B. kaber, D. stramonium and S. nigrum in order to avoid the risk of further expansion of whitefly populations where these weeds and both B- an Q-biotypes are present.  相似文献
3.
非形态特征在粉虱分类中的运用(同翅目:粉虱科)   总被引:5,自引:0,他引:5  
粉虱的分类主要利用第四龄幼虫 (蛹壳 )的特征而非成虫特征 ,而有的种类的形态有很大变异 ,完全依赖形态特征对某些种类 (特别是近缘种 )进行鉴定或鉴别是有困难的。因此 ,非形态特征的应用在粉虱分类中有一定的特殊价值。本文列举了一些可以用于昆虫分类的非形态特征 ,介绍了主要以非形态特征进行分类的特例——烟粉虱 Bemisia tabaci ( Gennadius)和银叶粉虱 Bemisia argentifolii Bellow &Perring的鉴别 ,并对非形态特征在分类中的合理运用进行了讨论。  相似文献
4.
Three tomato varieties (Motelle, Ronita, and VFN8) bearing the Mi-1.2 gene providing resistance to nematodes Meloidogyne spp. and to the potato aphid Macrosiphum euphorbiae Thomas, and three varieties not bearing this gene (Moneymaker, Roma, and Río Fuego), were compared by choice assay for host preference using the Q-biotype of Bemisia tabaci (Gennadius). The most preferred hosts, determined by infestation levels and numbers of feeding adults were Moneymaker, Río Fuego and Roma, all of which were not carrying the Mi gene. Ronita and Motelle, both of which bore the Mi gene, were the least preferred hosts. In a no-choice assay, B. tabaci females laid a significantly lower number of eggs on the varieties that carried the Mi gene than on those lacking the gene. Differences were more dramatic when plants carrying the Mi gene were pooled together and compared with pooled plants without this gene. Significantly greater values were obtained for the Mi-lacking group for all parameters tested. Comparing these results with those from a previous study on the B-biotype of B. tabaci, Q-biotypes were found to produce higher daily infestation rates on most of the tomato varieties. When results from plants carrying Mi were pooled, they showed lower infestation levels of Q-biotypes than B-biotypes. The Q-biotype infested less Mi-plants and more non-Mi plants than B-biotype. Q-biotype females produced significantly less pupae than the B-biotype females on both groups of plants. These results suggest the existence of an antixenosis and antibiosis-based resistance to the Q-biotype of B. tabaci in Mi-bearing commercial tomato varieties, which is greater than that previously reported for the B-biotype.  相似文献
5.
Stylet penetration by larvae of the greenhouse whitefly on cucumber   总被引:3,自引:0,他引:3  
Probing behaviour of Trialeurodes vaporariorum (Westwood) larvae was monitored using the DC electrical penetration graph (EPG) technique on the host plant cucumber. EPGs were recorded for 16 h, simultaneously with honeydew excretion using a honeydew clock. Three waveforms were distinguished: a pathway waveform (C), and two phloem waveforms, one with a high (H), and one with a low frequency (L) signal. The C waveform mainly occurred in the crawler stage of the 1st instar larvae. EPGs recorded from larvae during and after moulting indicated that the process involves stylet withdrawal; hence the stylets of each new instar need to penetrate again from the leaf surface to the phloem.All sessile stages, from L1 to pre-pupa, spent almost their entire time in waveforms H and L. These waveforms alternated more frequently in the early instars than during the later ones, in which the H waveform became predominant. The H waveform was highly correlated with honeydew excretion and thus phloem sap ingestion. The L waveform was not related to honeydew excretion but EPGs indicated that the stylet tips remain in a sieve element during both waveforms. Periods of honeydew production demonstrated a delay of 30–40 min in relation to the onset and end of H and L waveforms. This delay is presumably related to the time needed for food passing through, or emptying of, the insect's gut. From the 1st instar to the pre-pupa, the frequency of excreted honeydew droplets decreased but their size increased, causing a net increase of the excretion rate.  相似文献
6.
The capacity of the B biotype of the whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae), to invade has often been linked to its presumably wider host range than the non‐B indigenous biotypes. However, there are few experimental studies of the relative performance of the B biotype and non‐B biotypes on different host‐plant species. Here, we compared the performance of the B biotype and an indigenous non‐B biotype (China‐ZHJ‐1) of B. tabaci from Zhejiang, China on five commonly cultivated host plants, each from a different family: cotton, tobacco, cabbage, squash, and kidney bean. We also examined the effect of rearing host plants on the performance of the B biotype. Overall, the performance of the B biotype on the five species of plants was much better than that of the indigenous non‐B population. On tobacco, cabbage, and kidney bean, no individuals of ZHJ‐1 completed development to adulthood, whereas the B biotype developed successfully from egg to adult on all three plants. On squash, the B biotype survived better, developed to adulthood earlier and had a higher fecundity than ZHJ‐1. The two biotypes performed more equally on cotton, but even on this plant the B biotype female adults lived nearly twice as long as that of ZHJ‐1 and may have realized a higher life‐time fecundity. The B biotype also showed a substantial capacity to acclimatize to alternative host plants for improved survival and reproduction, on both highly suitable and marginally suitable host plants. We conclude that the host range of the B biotype of B. tabaci may be much wider than those of some indigenous biotypes, and this advantage of the B biotype over the non‐B biotypes may assist in its invasion and displacement of some indigenous biotypes in the field.  相似文献
7.
8.
中国新疆地区粉虱种类(半翅目:粉虱科)记述   总被引:2,自引:0,他引:2  
记述了新疆地区粉虱5属6种,即欧洲甘蓝粉虱Aleyrodes proletella(Linnaeus),葡萄穴粉虱Aleurolous shantungiTang,非洲小粉虱Bemisia afer(Priesner&Hosny),烟粉虱Bemisia tabaci(Gennadius),桑粉虱Pealius mori (Takahashi),温室白粉虱Trialeurodes vaporariorum(Westwood),其中葡萄穴粉虱为新疆新记录种.并且用扫描电镜对其伪蛹进行拍照,并依据玻片标本进行了描述.编制了新疆地区粉虱分类检索表.  相似文献
9.
A study was set up to determine the sources and rates of mortality of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) on field‐grown cassava in Uganda. Using a cohort‐based approach, daily direct observations were used to construct partial life tables for 12 generations of egg and nymph populations which were studied over a 1‐year period. Mortality was categorized as dislodgement, predation, parasitism (for nymphs only), unknown death, and inviability (for eggs only). The highest mean rate of marginal mortality across all stages was attributed to parasitism, with dislodgement and predation following, respectively. Across all factors, the highest mean rate of marginal mortality was observed in the fourth instar followed by the eggs, first‐, second‐, and third‐instars, respectively. Key factor analysis revealed that dislodgement was the major mortality factor contributing to generational mortality in eggs while for nymphs, parasitism in the fourth instar was the main driving force behind the observed generational mortality. Highest irreplaceable mortality in both the egg and nymph stages was attributed to dislodgement followed by parasitism and predation, and least was due to unknown death. Across stages, highest irreplaceable mortality rates were observed in the eggs and the fourth‐instar nymphs. The other stages had relatively low rates of irreplaceable mortality. Rain‐protection experiments revealed no significant differences in marginal mortality rates when compared to the open field situation.  相似文献
10.
The whitefly, Bemisia tabaci Gennadius (Homoptera: Aleyrodidae), harbors primary and secondary endosymbionts. Previous research showed that the invasive B biotype and an indigenous non‐B biotype (named non‐B ZHJ‐1 population) of B. tabaci from Zhejiang, China, harbored different endosymbionts. To investigate the function of these endosymbionts in the two biotypes of B. tabaci, we fed adult whiteflies with three antibiotics, tetracycline, ampicillin trihydrate, and rifampicin, and evaluated the fitness of their offspring on cotton plants. These three antibiotics did not remove the primary endosymbiont Portiera aleyrodidarum but were capable of eliminating the secondary endosymbionts. In the B biotype, treatments of adults with tetracycline or ampicillin trihydrate accelerated development and increased the survival of their offspring, while treatment of adults with rifampicin significantly retarded the development of their offspring but did not affect their survival. In the non‐B ZHJ‐1 population, treatments of adults with tetracycline or ampicillin trihydrate also accelerated the development of their offspring but did not significantly affect their survival, while treatment of adults with rifampicin significantly retarded development and reduced the survival of their offspring. These results suggest that removal of some secondary endosymbionts and/or reduction of the primary endosymbiont from B. tabaci may produce both favorable and unfavorable effects on the fitness of the host insects.  相似文献
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