Genetic Differentiation of Different Geographical Populations of Bemisia tabaci (Gennadius) Complex

Bemisia tabaci （Gennadius） is a species complex, which includes different geographical populations with genetic differentiation. The recent progress on the genetic differentiation of various geographical populations of B. tabaci complex was introduced. The genetic differentiation was further analyzed on the basis of the sequences of mtDNA COI and rDNA ITS1 recorded in the world＇s GenBank. Five groups are defined on the basis of mtDNA COI and rDNA ITS1, including the Asia group, America group, Africa group, Australia group, and Biotype B/Mediterranean/Middle East/ Northern Africa/Biotype Ms group. There are several ungrouped geographical classifications, such as the Uganda population, Ivory Coast population, and Taiwan population. Geographical isolation may be the most important factor that contributed to the genetic differentiation of various geographical populations of B. tabaci. Many populations with biological advantages invaded new regions and caused severe economic losses within human activity. It is necessary to strengthen the research of B. tabaci biotype to prevent the spread of invaded populations and the invasion of potentially dangerous populations.

Bemisia tabaci Phylogenetic Groups in India and the Relative Transmission Efficacy of Tomato leaf curl Bangalore virus by an Indigenous and an Exotic Population

Bemisia tabaci adults from various host-plant species were collected from 31 regions across India.266 B.tabaci samples were first screened by RAPD-PCR to examine molecular variability and to select individuals with different fingerprints.Host-plant and region of collection were then used to select 25 individuals for PCR amplification and sequencing of their partial mitochondrial cytochrome oxidase subunit one（mtCOI）genes.Pairwise comparisons with mtCOI consensus sequences showed that the majority of these samples had 〈3.5% sequence divergence from groups currently termed Asia I,Asia II-5,Asia II-7,and Asia II-8.The biotype-B B.tabaci from India clustered into the Middle East-Asia Minor 1 group.A new group of B.tabaci from Coimbatore,collected from pumpkin,was related most closely to the Asia I group（6.2% sequence divergence from the consensus Asia I sequence）.To increase our understanding of the epidemiology of tomato leaf curl disease（ToLCD）and the key B.tabaci genetic groups involved in virus spread,the indigenous Asia I and the exotic biotype-B population from South India were used to carry out transmission experiments using Tomato leaf curl Bangalore virus（ToLCBV）.The acquisition access periods（AAP）,inoculation access periods（IAP）,latent periods（LP）,and ToLCBV transmission efficiencies of the two populations were compared and the biotype-B had the more efficient transmission characteristics.These results are discussed in relation to recent changes in the epidemiology of tomato leaf curl disease in South India.

Sequence Analysis of mtDNA CO/Gene and Molecular Phylogeny of Different Geographical Populations of Bemisia tabaci (Gennadius)

Bemisia tabaci(Gennadius) is a serious pest in many cropping systems worldwide and occurs in different biotypes. ThemtDNA COI gene of the 12 Bemisia tabaci (Gennadius) populations from different regions and countries were analyzed.Based on mtDNA COI sequences, their biotypes were characterized and phylogenetic relationships among thesepopulations were established with the method of UPGMA. The results indicated the genetic similarity between thosepopulations from Beijing, Zhengzhou, Zaozhuang, Nanjing, Shanghai, Haikou, and the B-biotype populations fromCalifornia, Texas, Arizona reached 99.8-100%, which meant the nation-wide infested populations of B.tabaci in China inrecent years were B-biotypes. Another population collected from Kunming of Yunnan Province showed very high similaritywith Q-biotype B.tabaci from Spain and Morocco, which meant the Kunming population was Q-biotype. This is the firstreport on the invasion of Q-biotype into China.

Comparative Analysis of Population Genetic Structure in Bemisia tabaci(Gennadius) Biotypes B and Q Based on ISSR Marker

Bemisia tabaci （Gennadius） biotypes B and Q are two invasive biotypes in the species complex. The comparison of the population genetic structure of the two biotypes is of significance to show their invasive mechanism and to their control. The intersimple sequence repeats （ISSR） marker was used to analyze the 16 B-biotype populations and 4 Q-biotype populations worldwide with a Trialeurodes vaporariorum population in Shanxi Province, China, and a B. tabaci non-B/Qbiotype population in Zhejiang Province, China, was used as control populations. The analysis of genetic diversity showed that the diversity indexes of biotype Q including Nei＇s gene diversity index, Shannon informative index, and the percentage of polymorphic loci were higher than those of biotype B. The high genetic diversity of biotype Q might provide the genetic basis for the excellent ecological adaptation. Cluster analysis suggested that the ISSR could not be used in the phylogenetic analysis though it could easily distinguish the biotypes of B. tabaci. The difference of the population genetic structure between the biotype B and the biotype Q exists based on the ISSR marker. Meanwhile, the results suggested that the molecular marker has its limitation in the phylogenetic analysis among the biotypes of B. tabaci.

Genetic mutations associated with chemical resistance in the cytochrome P450 genes of invasive and native Bemisia tabaci （Hemiptera： Aleyrodidae） populations in China

Bemisia tabaci （Gennadius） is a species complex, and its two most damaging biotypes B and Q are globally distributed pests. Despite increasing biological and economic impacts, little is known about the evolutionary mechanisms that favor their competition with native populations. Here, we investigated the genetic mutations in the P450 gene of the invasive B, Q biotypes and the native Cv population. Four mutations associated with chemical resistance, Pro-Leu, Ala-Ser, Ser-Phe and Trp-Leu, were found in the cytochrome P450 CYP6C and CYP9F genes of the B and Q biotypes. Bioassay results also revealed that both the B and Q biotypes have about 12-47 times more resistance to acephate, beta- cypermethrin, methomyl, and 5-7 times more resistance to imidacloprid insecticide than Cv population. Our results provide a molecular approach for better understanding and monitoring the pesticide resistances of invasive and native B. tabaei populations in China.

Effect of planting date and nitrogen fertilization on photosynthesis and soluble carbohydrate contents of cotton in relation to silverleaf whitefly （Bemisia tabaci biotype “B”） populations

The impacts of planting date and nitrogen fertilization on cotton （Gossypium hirsutum L.） photosynthesis and soluble carbohydrate contents in relation to silverleaf whitefly, Bemisia tabaci （Gennadius） biotype “B”, populations were examined in field experiments. Cotton planted in late April and early June was treated with 0, 112, 168 and 224 kg/N hectare in soil using urea fertilizer. The mean photosynthetic rate of April-planted cotton was 4%-20% higher than that of June-planted cotton early in the season, but 10%- 18% lower than that of June-planted cotton late in the season. The photosynthetic rates for both planting dates were positively correlated with levels of added nitrogen. While levels of glucose for both planting dates were positively correlated with nitrogen levels, fructose and sucrose levels were not. The mean levels of fructose were up to 40% lower, while that of sucrose were up to 59% higher, in April-planted cotton than in June-planted cotton. Levels of photosynthetic rate or stomatal conductance were not correlated with adult whitefly densities for either planting date. Levels of glucose and fructose were positively correlated with whitefly densities only for June-planted cotton late in the season.

Genetic structure of the whitefly Bemisia tabaci populations in Colombia following a recent invasion

The whitefly Bemisia tabaci （Gennadius） is one of the most important pests causing economic losses in a variety of cropping systems around the world. This species was recently found in a coastal region of Colombia and has now spread inland. To investigate this invasive process, the genetic structure of B. tabaci was examined in 8 sampling locations from 2 infested regions （coastal, inland） using 9 microsatellite markers and the mitochondrial COI gene. The mitochondrial analysis indicated that only the invasive species of the B. tabaci complex Middle East-Asia Minor 1 （MEAM 1 known previously as biotype B） was present. The microsatellite data pointed to genetic differences among the regions and no isolation by distance within regions. The coastal region in the Caribbean appears to have been the initial point of invasion, while the inland region in the Southwest showed genetic variation among populations most likely reflecting founder events and ongoing changes associated with climatic and topographical heterogeneity. These findings have implications for tracking and managing B. tabaci.

Heterogeneous distribution of Cardinium in whitefly populations is associated with host nuclear genetic background

Inherited bacterial symbionts are very common in arthropods, but infection frequency can vary widely among populations. Experiments and interpopulation comparisons suggest that host genetic background might be important in explaining this variation. Our extensive field investigation showed that the infection pattern of the facultative symbiont Cardinium was heterogeneous across geographical populations of the invasive whitefly Bemisia tabaci Mediterranean (MED) in China, with genetic nuclear differences evident in 2 of the populations: 1 with a low infection rate (SD line) and 1 with a high infection rate (HaN line). However, whether the heterogeneous frequency of Cardinium is associated with the host genetic background remains poorly understood. Here, we compared the fitness of the Cardinium-infected and uninfected sublines with similar nuclear genetic backgrounds from SD and HaN lines, respectively, and further determine whether host extranuclear or nuclear genotype influenced the Cardinium–host phenotype by performing 2 new introgression series of 6 generations between SD and HaN lines (i.e., Cardinium-infected females of SD were backcrossed with uninfected males of HaN, and vice versa). The results showed that Cardinium provides marginal fitness benefits in the SD line, whereas Cardinium provides strong fitness benefits in the HaN line. Further, both Cardinium and the Cardinium–host nuclear interaction influence the fecundity and pre-adult survival rate of B. tabaci, whereas the extranuclear genotype does not. In conclusion, our results provide evidence that Cardinium-mediated fitness effects were closely associated with the host genetic background, which provides a fundamental basis for understanding the mechanism underlying the heterogeneous distribution of Cardinium in B. tabaci MED populations across China.

基于地统计学的新疆棉田烟粉虱(Bemisia tabaci(Gennadius))危害动态与时空分布

应用地统计学（GS）的原理与方法研究了外来入侵有害牛物烟粉虱（Bemisia tabaci（Gennadius））为害新疆棉田的时空动态，并与经典统计学进行对比分析。两种方法一致表明，烟粉虱成虫在空间上呈聚集分布的格局，而各时期成虫的聚集程度依据空间变异随机程度所占的比例不同而不同。经频次分布检验，以零频率法参数拟合的负二项分布来表达其空间分布型最为合适。运用Gs的分析方法，进一步得到种群分布面积变化与扩散的趋势，并依此对昆虫种群的扩散模型进行模拟。棉田烟粉虱成虫在田间7-8月份均存在一定的空间相关性，随机程度为19．22％-49．99％；空间相关距离（相关程）在一个月内从32m急速增至6372m，随后在2000-3000m的范围波动。从整个发生过程看出，烟粉虱从越冬场所顺风侵入大田后，迁飞扩散在很大程度上受风向的影响，属于典型的借助风力扩散的昆虫，其在棉田的垂直分布则与吐鲁番地区独特的暖温带大陆性干旱荒漠气候特征有关。顺风扩散时多从棉株上部叶片开始危害，而逆风扩散时从棉株中、下部叶片危害。烟粉虱在棉株上建立稳定种群后，中、下部虫口密度要略高于上部，这是烟粉虱对吐鲁番地区特殊气候的适应。

寄主植物对B型烟粉虱(Bemisia tabaci)和温室粉虱(Trialeurodes vaporariorum)个体发育和种群繁殖的影响

烟粉虱Bemisia tabaci(Gennadius)和温室粉虱Trialeurodes vaporariorum(Westwood)在我国北方常混合发生,为了解两种粉虱所造成的危害和自身种群的增长变化,制定科学的综合防治措施,在(27±1)℃条件下研究了两种粉虱在棉花Gossypium hirsutum L.(泗棉3号)、黄瓜Cucumis sativas L.(北京202)、茄子Solanum melongena L.(北京七叶茄)和番茄Lycopersicum esculentum Mill.(佳粉十号)上各虫态大小、存活率、发育历期、成虫寿命、平均产卵量等生物学参数。在同一种寄主植物上,温室粉虱的1,2龄若虫的体长和体宽均显著大于烟粉虱,3龄以后两种粉虱的体型则变异较大。两种粉虱从卵到成虫羽化,在棉花上的发育历期无显著差异,在黄瓜、茄子和番茄上,温室粉虱的发育历期(19.7、19.4、20.8d)显著长于烟粉虱(17.3、17.6、18.3d)。在黄瓜和番茄上,烟粉虱的平均寿命(31.2、32.1)显著长于温室粉虱的平均寿命(26、24.9d);在棉花、黄瓜和番茄上,烟粉虱的单雌产卵量(122.2、220.2、266.5粒)显著高于温室粉虱(97.1、186.6、197.1粒)。烟粉虱在棉花、黄瓜、茄子和番茄上的总存活率分别为67.9%、77.8%、67.8%和59.0%,温室粉虱依次为62.2%、67.2%、64.4%和66.1%。综合比较4种寄主植物,烟粉虱比温室粉虱具有个体发育时间短、种群繁殖速度快、生殖竞争能力强等特点。

寄主植物对B型烟粉虱(Bemisia tabaci)几种主要解毒酶活性的影响

研究测定了棉花、一品红、茄子和番茄4个B型烟粉虱(Bemisia tabaci)种群α-NA羧酸酯酶、β-NA羧酸酯酶、乙酰胆碱酯酶和谷胱甘肽S-转移酶活性。结果表明:α-NA羧酸酯酶活性与β-NA羧酸酯酶活性比值均大于1,说明B型烟粉虱水解α-NA的能力高于对β-NA的水解能力;B型烟粉虱不同寄主种群α-NA羧酸酯酶、β-NA羧酸酯酶活性个体分布频率均存在一定差异。B型烟粉虱番茄种群羧酸酯酶活性最高(93.06 mOD/(mg protein.min)),是棉花种群的1.49倍。B型烟粉虱茄子种群乙酰胆碱酯酶活性明显高于其他寄主种群,达极显著差异水平(p<0.01);茄子种群乙酰胆碱酯酶活性分布频率在>4U/mgprotein区间段的分布高达85%,与其他3个寄主种群分布明显不同。B型烟粉虱茄子种群谷胱甘肽S-转移酶活性最高,与其他3个寄主种群间的差异达极显著水平(p<0.01)。上述结果表明,B型烟粉虱主要解毒酶活性在不同的寄主植物上具有一定的生理可塑性。研究有利于揭示该害虫寄主范围广和寄主适应性强的生理生态学基础。

烟粉虱(Bemisia tabaci)的寄主选择性

通过田间系统调查、实验室嗅觉测定、笼内和培养皿内自由扩散观察,对烟粉虱的寄主选择性进行了研究。结果表明,在田间,烟粉虱对不同的寄主植物存在明显的寄主选择性,其中对茄子、花椰菜、黄瓜等植物具有较强的嗜性,而对蕹菜、芹菜、苋菜等植物的嗜性较差;烟粉虱对同一植物的不同品种也有明显的选择性。烟粉虱对寄主植物颜色有明显的选择性,选择结果与烟粉虱对这些寄主的嗜性趋势基本一致。烟粉虱对单株寄主植物的嗅觉反应不敏感,但对植物叶片的乙醇抽提物有明显的嗅觉反应,并表现出较强的寄主选择性。在养虫笼内,烟粉虱从虫源皿向寄主植物自由扩散的过程中,在不同寄主植物和同一植物的不同品种上着落的成虫数量不同,并且在一定的时间范围内,着落在寄主叶片上的虫量还会不断的发生变化。

淡色斧瓢虫(Axinoscymnus cardilobus)对烟粉虱(Bemisia tabaci)种群的控制作用

研究了大田笼罩条件下释放淡色斧瓢虫（Axinoscymnus cardilobus）对变叶木上烟粉虱种群的控制作用。每株释放1对淡色斧瓢虫对不同密度烟粉虱种群的控制效果差异显著。瓢虫和烟粉虱以1∶20比例释放对烟粉虱的防治效果较差,以1∶80比例释放对烟粉虱的防治效果不稳定、总体上看对烟粉虱的种群几乎没有控制效果;而以1∶40的比例释放的防治效果较好、较稳定,防效为35%～95%。释放不同数量的淡色斧瓢虫对同一密度烟粉虱种群的防治效果也差异显著。7周内在1∶40、3∶40、5∶40处理区,瓢虫对烟粉虱种群的防治效果分别为35%～95%、46%～90%和50%～98%。从经济学和生态学的角度综合考虑,瓢虫和烟粉虱以3∶40比例释放比较适宜。

蜡蚧轮枝菌Lecanicillium lecanii次生代谢产物对烟粉虱Bemisia tabaci的忌避作用模型

蜡蚧轮枝菌Lecanicillium lecanii(Z imm.)viegas V l6063菌株在2种不同培养基发酵培养后,经萃取、干燥浓缩得到4种不同的毒素粗提物(次生代谢产物),用均匀设计法设计实验方案研究了4种不同毒素粗提物对4种不同寄主植物上烟粉虱Bem isia tabaci(Gennad ius)成虫的忌避作用,并构建了模型,分析结果表明,忌避作用与毒素粗提物浓度显著相关,忌避率随毒素粗提物浓度增大而增大,1 g/L浓度的毒素粗提物忌避率与烟粉虱的寄主植物相关不显著,毒素的忌避作用与培养基相关不显著,从菌株发酵的菌丝体和发酵液中提取的毒素粗提物的忌避率差异不显著。

不同寄主植物的烟粉虱(Bemisia tabaci)内共生菌传毒相关GroEL蛋白的一致性

通过对7种寄主植物上B型烟粉虱北京种群的内共生菌传毒相关groEL基因进行PCR扩增和测序,结合已有的相关序列,构建了groEL基因及其编码的GroEL蛋白的分子系统树。结果表明:烟粉虱内共生菌产生的groEL基因是一个非常保守的基因,北京不同寄主植物的烟粉虱内共生菌与IsraelB型烟粉虱内共生菌的groEL基因亲源关系非常近,位于同一进化分支,其编码的GroEL蛋白的分子系统树也基本上是一致的。不同物种的groEL基因及其编码的GroEL蛋白分别位于不同的分支,说明groEL基因及其编码的GroEL蛋白的分子系统树可以用于分析物种间的进化关系。氨基酸序列比较表明:烟粉虱内共生菌GroEL具有原核GroEL的保守氨基酸、ATP酶活性位点、多肽结合位点和GroES连接位点,为典型的hsp60。不同来源烟粉虱内共生菌GroEL有少数几个保守氨基酸发生了置换,可能不是GroEL功能的重要位点。说明在容易变异的细菌基因组中,groEL基因为了维持其正常重要的生理功能,会通过保持功能位点的稳定性来应对不同生态因素的影响。

瓜菜害虫Q型烟粉虱Bemisia tabaci(Gennadias)形态特征研究

为了准确描述Q型烟粉虱Bemisia tabaci(Gennadias)各个龄期的形态特征,应用超景深显微镜(VHX-600)和扫描式电子显微镜(S-3400NII)对寄主植物黄瓜上Q型烟粉虱进行了详细的记录和观察。结果表明,烟粉虱的卵呈长梨形;1龄若虫边缘刚毛16对,可爬行;2龄若虫眼点明显,边缘呈圆齿状;3龄若虫体色变浅,胸气门、尾气门可见,眼点变红色;4龄若虫椭圆形,体黄色,皿状孔三角形,舌状突长匙状。成虫淡黄白色,翅2对,覆盖白色蜡粉,雌虫体长(0.91±0.04)mm,翅展(2.13±0.06)mm;雄虫略小。停息时左右翅合拢呈屋脊状,并稍分开,可见黄色的腹部。研究结果为Q型烟粉虱的鉴定提供了形态依据。

Diversity and Genetic Differentiation of the Whitefly Bemisia tabaci Species Complex in China Based on mtCOI and cDNA-AFLP Analysis

The whitefly Bemisia tabaci are considered as a taxonomically complex that contained some destructive pests.Two of the most prevalent cryptic species are B.tabaci Middle East-Asia Minor 1（MEAM1）and Mediterranean（MED）.In an extensive field survey of the B.tabaci complex present throughout part of China from 2004 to 2007,we obtained 93 samples of B.tabaci from 22 provinces.We determined that these Chinese haplotypes included 2 invasive species（MEAM1 and MED）,and 4 indigenous cryptic species（Asia II 1,Asia II 3,China 3 and Asia II 7）by sequencing mitochondrial cytochrome oxidose one gene（mtCOI）.The diversity and genetic differentiation of a subset of 19 populations of B.tabaci were studied using cDNA amplified fragment length polymorphism（AFLP）.Prior to 2007,MEAM1 was a dominant species in many provinces in China.By 2007,MED was dominant in 11 provinces.Both invasive and indigenous species were simultaneously found in some regions.Indigenous species of B.tabaci were found in six provinces in southern China.MED and MEAM1 have broad ranges of host plants,and indigenous species appeared to have much narrower host ranges.All Asia II 3 samples were found on cotton except one on aubergine.China 3 has more host plants than Asia II 3.Twelve samples of China 3 were collected from sweet potato,Japanese hop,squash and cotton.A total of 677 reproducible bands amplified with 5 AFLP primer combinations were obtained.The highest proportion of polymorphic bands was 98.7% and the lowest was 91.9%.Unweighted pair-group method analysis indicated that the clustering was independent of the different species.MED showed the lowest degree of similarity than the other species.The data indicate that both MEAM1and MED were rapidly established in China.

Density and Seasonal Dynamics of Bemisia tabaci(Gennadius) Mediterranean on Common Crops and Weeds Around Cotton Fields in Northern China

The density seasonal dynamics of Bemisia tabaci MED were evaluated over two years in a cotton-growing area in Langfang, Hebei Province, northern China on cotton （Gossypium hirsutum L.） and six other co-occurring common plants, common ragweed （Ambrosia artemisiifolia L.）, piemarker （Abutilon theophrasti Medicus）, sunflower （Helianthus annuus L.）, sweet potato （Ipomoea batatas L.）, soybean （Glycine max L.）, and maize （Zea mays L.）. The whitefly species identity was repeatedly tested and confirmed; seasonal dynamics on the various host plants were standardized by the quartile method. B. tabaci MED appeared on weeds （the common ragweed and piemarker） about 10 days earlier than on cotton, or the other cultivated plants. The peak population densities were observed over a span of 2 to 3 weeks on cotton, starting in early （2010） or mid-August （2011）. The common ragweed growing adjacent to cotton supported the highest B. tabaci densities （no. on 100 cm2 leaf surface）, 12-22 fold higher than on cotton itself. Sunflower supported more B. tabaci than the other plants, and about 1.5-2 fold higher than cotton did, Our results indicate that weeds （esp. the common ragweed） around cotton fields could increase the population density of B. tabaci MED on cotton, while sunflower could act as a trap crop for decreasing pest pressure on cotton.

Transmission characteristics of Tomato chlorosis virus (ToCV) by Bemisia tabaci MED and its effects on host preference of vector whitefly

The epidemiology of Tomato chlorosis virus(ToCV)in China is closely associated with its vector whitefly,Bemisia tabaci(Gennadius)MED.However,the transmission characteristics of ToCV by B.tabaci MED remain poorly understood.In this study,we analyzed:1)the horizontal and vertical transmission of ToCV by B.tabaci MED whiteflies;2)the acquisition of ToCV by male and female B.tabaci MED whiteflies after different feeding durations;3)the transmission efficacy of viruliferous male and female B.tabaci MED whiteflies after different inoculation access periods(IAPs);4)the retention of ToCV by viruliferous male and female B.tabaci MED whiteflies after a 48 h acquisition access period(AAP);and 5)the effects of ToCV on host choice of healthy or ToCV-infected tomato plant of viruliferous and non-viruliferous B.tabaci MED at different time points.Our results showed that:1)viruliferous males could not transfer ToCV to non-viruliferous females,and vice versa,viruliferous females could not pass on ToCV to non-viruliferous males.ToCV could not be detected in the F1 generation adults;2)ToCV could be detected within 4.0%of females or males after a 20 min AAP;3)ToCV could be detected in 33.3%of tomato plants inoculated by 10 viruliferous males or females with IAPs of 20 or 30 min;4)the maximum retention time in females was 7 and 5 days in males;and 5)non-viruliferous B.tabaci MED did not show a preference for ToCV-infected tomato plants or healthy tomato plants.However,viruliferous B.tabaci MED whiteflies did prefer to settle on healthy tomato plants over ToCV-infected tomato plants.These findings will be helpful to better understand the epidemiology of the recently emerged plant virus,ToCV,in tomato fields in China.

Enhancement of Phenylalanine Ammonia Lyase,Polyphenoloxidase,and Peroxidase in Cucumber Seedlings by Bemisia tabaci (Gennadius) (Hemiptera:Aleyrodidae) Infestation

In this study, the activities of phenylalanine ammonia lyase （PAL）, polyphenoloxidase （PPO）, and peroxidase （POD） were assayed in cucumber seedlings （Cucumis sativus L.） at 0, 6, 12, 24, 48, 72, and 96 h after they were infested by Bemisia tabaci （Gennadius） using spectrophotometric analysis. The results indicated that herbivore infestation increased the activities of PAL, PPO, and POD. The enzymes showed different activity levels at different times after the infestation. The PAL activity reached the first high peak by 23.1% at 6 h and the highest peak by 29.1% at 48 h compared to the control. The PPO activity reached the first high peak by 22.7% at 6 h and the highest peak by 52.6% at 24 h, and the POD activity reached the highest peak by 213.2% at 6 h and another higher peak value by 135.2% at 96 h. The results suggest that the enhanced activities of the enzymes may contribute to bioprotection of cucumber plants against B. tabaci infestation.