印度藏茴香植物精油对温室棉蚜的熏蒸毒性及其成分分析（英文）

【目的】棉蚜Aphis gossypii是世界各地室内和室外果树、蔬菜和观赏植物上最具危害性的害虫之一。这一害虫取食植物汁液,产生蜜露,传播植物病毒,对植物从质和量上产生破坏。为了控制温室中的这一害虫,植物精油可用作化学农药的替代药物。本实验研究了印度藏茴香Carum copticum植物精油对棉蚜成虫的熏蒸毒性。【方法】将研磨的印度藏茴香干种子用改良的挥发油提取器(Clevenger-type apparatus)进行水蒸馏。所有生物测定均在27±2℃,相对湿度65%±5%和光周期16L∶8D条件下进行。研究采用完全随机设计,6个处理(5个不同浓度的精油加对照)。每一浓度3次重复,每一重复20头成虫。【结果】结果表明,棉蚜成蚜接触印度藏茴香精油24 h后出现明显的死亡。该精油对棉蚜成蚜的致死中浓度(LC50)为1.21μL/L空气。棉蚜成蚜的死亡百分率对精油的施用表现出较高的敏感性。精油浓度为1.21μL/L空气时,估计的棉蚜的致死中时(LT50)为11.79 h。这一精油的熏蒸毒性与浓度和接触时间之间具有一定的相关性。GC/MS组分分析结果表明,该精油由18种化合物组成,最重要的是一些化合物引起了熏蒸毒性,如麝香草酚(占50.07%)、γ-萜品烯(占23.99%)和对异丙基苯甲烷(占22.90%)。【结论】本研究结果表明印度藏茴香植物精油对棉蚜具有较好的杀虫效果。印度藏茴香精油对棉蚜产生较大的影响,由于它具有较高的熏蒸毒性潜力,因此可在温室中用于这一害虫的综合治理。     

Chemical constituents and fumigant toxicity of essential oil from Carum copticum against two stored product beetles

Plant secondary metabolites play an important role in plant-insect interactions and therefore such compounds may have insecticidal or antifeedant activity against insects. Carum copticum C. B. Clarke （Apiaceae） is one of these plants that have medicinal effects on humans. The chemical composition of the essential oil from dry seeds of C. copticum was studied by gas chromatography （GC） and gas chromatography mass spectrometry （GC-MS）. Thymol （41.34%）,α-terpinolene （17.46%） and ρ-cymene （11.76%） were found to be the major constituents of the oil. In fumigant toxicity tests with the essential oil against adults of Sitophilus oryzae （L.） and Tribolium castaneum （Herbst） at 27 ±1℃ and 60% ± 5% RH, it was observed that S. oryzae （LC50 = 0.91 μL/L） were significantly susceptible than T. castaneum （LC50 = 33.14 μL/L）. The mortalities of the insect species reached 100% at concentrations higher than 185.2 μL/L and 12-h exposure time. The findings indicate the strong insecticidal activity of C. copticum oil and its potential role as a fumigant for storedproduct insects.     

Effect of lemon essential oil on the developmental stages of Trialeurodes vaporariorum West (Homoptera: Aleyrodidae)

Trialeurodes vaporariorum (Homoptera: Aleyrodidae), is a destructive pest of many ornamental and greenhouse crops throughout the world. In this research, effect of essential oil derived from lemon peel, Citrus aurantifolia (Hook.) on mortality of eggs, first-instar nymphs and on adult oviposition of T. vaporariorum (Westwood) was determined under laboratory conditions. Analysis of Citrus aurantifolia essential oil used for insect fumigation by phase gas chromatography revealed the presence of 16 compounds including Limonene (56.6%), β-pinene (16.3%) and α-terpineol (11.3%). Five concentrations of essential oil – 0.002, 0.004, 0.008, 0.016 and 0.032 (μl/ml) – were applied in fumigant toxicity experiments. Greater mortality was observed with increasing dose of essential oil. First-instar nymphs were more sensitive to essential oil treatments compared with eggs and adults that reduced the survival rate of T. vaporariorum by 58, 70 and 56% after treatment of eggs, nymphs and adult, respectively. Based on this study, essential oil derived from C. aurantifolia could be used as an effective and environmentally sustainable bioinsecticide for the control of T. vaporariorum.     

温室白粉虱自动计数技术研究初报

应用计算机视觉技术对温室白粉虱自动计数技术进行了研究。采用胶卷照相机和家用摄像机对田间温室白粉虱等生的叶片进行拍摄,以获得其数字图象,对白粉虱图象的分割采用Ｊohannsen基于熵的分割算法,对分割后的二值图象利用区域标记算法得到白粉虱个体的数量。对叶片挨在一起的白粉虱个体采用数学形态学算法进行了分离。用１９个虫叶片样本的统计结果表明,直接利用分割图象进行白粉虱个体计数的累积准确率达９１．９９％,而分离处理的算法则需要改进,因此,这一技术具有进一步在生态研究和ＩＰＭ实践中推广的可能性,这将使田间微小昆虫的种群数量监测和测查的工作量大幅度降低,而铉得到显著提高。     

Functional response of Nesidiocoris tenuis (Hemiptera: Miridae) to Trialeurodes vaporariorum (Hemiptera: Aleyrodidae): effect of different host plants

The influence of three host plants, namely cucumber, tomato and eggplant, on functional response of male, virgin and mated female predatory bug Nesidiocoris tenuis was investigated on different densities of Trialeurodes vaporariorum nymphs. The 24-h experiment conducted at laboratory conditions revealed that N. tenuis exhibited a type II functional response to T. vaporariorum on host plants. There were no significant differences between attack rates, as well as handling times estimated for each adult stage of the predator between host plants. However, on each host plant, the handling time estimated for the mated female in comparison with two other adult stages had lower values (0.7952, 0.6827 and 0.8884?h^?1 on cucumber, tomato and eggplant, respectively). Handling time estimated for the mated female on cucumber was significantly lower than that estimated for the male predator. The highest maximum handling rate (T/T_h) was estimated for the mated female followed by the virgin female and male on all host plants. For three adult stages of the predator, the highest value of this parameter was determined on tomato followed by cucumber and eggplant. Unlike virgin and mated females, the host plant significantly affected prey consumption by the male. Prey consumed by mated females was higher than those obtained for two other adult stages of the predator on each host plant. The difference in trichome density between three host plants may be responsible for the obtained results. These results revealed that N. tenuis is more effective in the biological control of T. vaporariorum on tomato in comparison with cucumber and eggplant.     

Predation of Clitostethus arcuatus (Col.: Coccinellidae) on Trialeurodes vaporariorum (Hem.: Aleyrodidae)

Greenhouse whitefly, Trialeurodes vaporariorum, is a serious pest of glasshouse crops. It shows resistance to different insecticides and growers are interested in finding other useful control methods. This research was carried out to study the predation potential and biology of Clitostethus arcuatus (Rossi) as one of the most important predators of this pest. Adult C. arcuatus were reared on tobacco leaves bearing colonies of greenhouse whitefly eggs under controlled conditions (25±2°C, 65±5% RH and 16 h L:8 h D). Results showed that the average developmental time of the egg, first through fourth instar larva and pupa were 2.82±0.12, 4.47±0.14, 4.54±0.1, 6.3±0.2, 7±0.22 and 3.8±0.13 days, respectively; and longevity of female and male were 66.4±2.6 and 54.9±2.5 days, respectively. The average feeding rates of female, male and larvae (first through fourth) were 61.4±0.7, 27.6±0.9 eggs/day and 12±1.03, 30.3±2.4, 41.3±2, 68.04±2 eggs/day, respectively. The larvae consumed an average of 992.2±36 eggs during the total larval developmental period with a daily mean of 45.8±0.5. A significant difference was shown between the feeding rate of fourth instar larval stages and between sexes. Females, males and one pair of C. arcuatus (♀,♂) consumed an average of 17.2±0.4, 10.6±0.8, 23.1±0.5 nymph/day; 28.5±0.9, 20.3±0.6, 47.2±0.6 pupa/day and 8±0.3, 6.5±0.54, 13.6±0.4 adult/day, respectively. The feeding rate was significantly different among whitefly life stages. Females laid an average of 3±0.23 eggs/day.     

Toxicity of abamectin and imidacloprid on different life stages of Trialeurodes vaporariorum (Westwood) reared on two different host plants under greenhouse conditions

Chemical application is the common control technique of the pest Trialeurodes vaporariorum (Westwood) (Hom.: Aleyrodidae). Toxicity of two insecticides abamectin and imidacloprid in 2009 was evaluated on different life stages of the pest. Bioassay tests were carried out under controlled environmental conditions (25?±?2?°C 50?±?5% RH and a photoperiod of 18:6 L/D) on different stages of whitefly (1-,3- and 5-day-old ages of eggs, first, second and third nymphal instars, pupa and adult). Both insecticides showed their best efficacy on the primary stages; though, with increasing the age, the susceptibility of all stages to chemicals was decreased. It was shown that sensitivity of eggs and first nymphal stage to abamectin in each host was different. But in imidacloprid treatment, only the eggs showed different sensitivity on both host plants. It seems that application of abamectin in primary stages induce higher mortality rates than of imidacloprid.     

Phototactic behavior of Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae) under visible wavelengths

The greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), is one of the most important pests of greenhouse crops. The intensive use of chemical insecticides has resulted in insecticide resistance in T. vaporariorum and the critical level of pesticides residue in crops. It is therefore necessary to develop new control methods based on ecological pest management. The present study was designed to control greenhouse whitefly by finding and using insect repellent wavelengths. The repellent wavelength experiment was conducted by a two-way phototactic apparatus given a choice between darkness and visible wavelength spectrum from violet (380–450 nm) to red (620–750 nm). The phototactic responses of the greenhouse whitefly were then investigated in a four-way phototactic apparatus given a choice between two light regimes, light-emitting diode (LED) and sunlight. The results indicated that the lowest (69.2%) and highest (97.8%) number of whiteflies were attracted to violet and orange (590–625 nm) spectra, respectively. In addition, the present study indicated a significant attraction of T. vaporariorum adults to sunlight compared with LED. Furthermore, the eggplants grown under growth LEDs showed a significantly higher growth rate than the plants grown under sunlight. These findings suggest that this type of LED not only has positive effects on plant growth but it also has a repellent activity on T. vaporariorum adults, leading us to develop an effective behavioral control of the greenhouse whitefly.     

Insecticidal effects of Artemisia dracunculus L. (Asteraceae) essential oil on adult of Aphis gossypii Glover (Hemiptera: Aphididae) under laboratory conditions

Aphis gossypii Glover (Homoptera: Aleyrodidae) is one of the most important pests of agriculture worldwide. To control the pest population, research on the use of the environmental and plant-based compounds has increased in recent decades. So, in this study, effect of fumigant toxicity of Artemisia dracunculus L. essential oil on adults of the mentioned pest was studied. The essential oil of this plant was subjected to hydro-distillation using a Clevenger apparatus. All bioassay examinations were conducted at 27?±?2 and 65?±?5?°C relative humidity and a photoperiod of 16:8?h (light:dark). This research was performed in a completely random design with six treatments in different concentrations and times to evaluate the level of LC₅₀ and LT₅₀. Each treatment was evaluated in three replicates for different concentrations and times with each replicate consisting of 20 same-age adult pests. The results showed that the use of the essential oil of A. dracunculus L. shows significant mortality of pest 24?h after treatment. LC₅₀ value of this essential oil on adults of A. gossypii was 18.63?μL/L of air and LT₅₀ value of the essential oil on the mentioned pest resulted to be 10.74?h with a concentration of 18.63?μL/L of air. The results showed that by increasing the concentration and duration of essence treatment, the mortality rate also increased. Experiment results showed that A. dracunculus L. oil has strong effect on the above-mentioned pest and it will be suggested for using in the mentioned integrated pest management programmes in greenhouses for its high potential in fumigant toxicity.     

Laboratory and field evaluation of biological active substances of plant origin against greenhouse whitefly,Trialeurodes vaporariorum Westw. (Homoptera: Aleyrodidae)

Abstract

The behavioural responses of greenhouse whitefly to substances of plant origin were investigated in laboratory and greenhouse conditions. The following species of plants were found to provide the most active chemicals to monitor and control greenhouse whitefly – laurel Laurus nobilis L., mullein Verbascum thapsus L., tansy Tanacetum vulgare L., wormwood Artemisia vulgare L.     

Impacts of two conventional insecticides on different stages of Encarsia inaron Walker parasitizing the whitefly,Trialeurodes vaporariorum Westwood under greenhouse condition

In this research, for the first time, compatibility of imidacloprid and pyriproxyfen was assayed with both pupa and adult stages of Encarsia inaron Walker parasitizing Trialeurodes vaporariorum Westwood. First, the insecticides were sprayed on bean plants containing the parasitoid pupae, thenceforth, survival of the adult parasitoid was evaluated 24 h post-exposure to fresh, 1-, 4-, 7-, 14-, and 21-day-old residues of them on bean leaflets in Petri dishes. Both insecticides significantly reduce E. inaron adult emergence. Mortality of the parasitoid pupa in treatment with imidacloprid (69.7%) was significantly higher than mortality with pyriproxyfen (28.6%). Pyriproxyfen was non-toxic to the adult parasitoid when residues were dried in fresh and aged through the experiment, while in the same condition, imidacloprid significantly killed the adult parasitoids up to 7 days after application. Results have been discussed on the potential compatibility of the insecticides with E. inaron in an integrated pest management (IPM) approach.     

B型烟粉虱和温室白粉虱在温度逆境下的生存特性比较

为了明确B型烟粉虱和温室白粉虱在温度逆境下的生存特性对其种群发展的影响,通过进行高温和低温暴露试验,研究了B型烟粉虱和温室白粉虱卵、伪蛹、成虫在37℃,39℃,41℃,43℃,45℃下暴露1～2 h后的存活率,以及这两种粉虱卵、2～3龄若虫、伪蛹和成虫在2℃下暴露1～12 d后的存活率。结果表明：两种粉虱的卵、伪蛹和成虫在37℃～45℃下暴露1～2 h,其存活率均随着温度的上升而降低;但在相同处理条件下B型烟粉虱3种供试虫态的存活率要高于温室白粉虱。B型烟粉虱在2℃下暴露2～12 d,各供试虫态的存活率迅速下降,卵、2～3龄若虫、伪蛹在2℃下暴露12 d后均不能存活,成虫在2℃下暴露4 d后也全部死亡;而温室白粉虱卵、伪蛹在2℃下暴露12 d后其存活率还能超过45%,成虫在2℃下暴露7 d后仍有80.9%能够存活。结果说明,B型烟粉虱和温室白粉虱对温度逆境的适应性存在差异,B型烟粉虱对高温的适应性要高于温室白粉虱;温室白粉虱对高温敏感,但对低温的适应性要显著高于B型烟粉虱。据此推测,两种粉虱对温度逆境适应性的差异是导致其种群发生存在差异的一个重要原因。     

两种杀虫真菌制剂与低用量吡虫啉对温室粉虱的协同防效评价

在昆明市郊蔬菜基地4间大棚(5m×100m·间^-1)栽培的生菜上,用球孢白僵菌(Beauveriabassiana)和玫烟色拟青霉(Paecilomyces fumasonoseus)的纯孢子乳悬剂(有效含孢量10^10·ml^-1)及其与1％和3％(w／v)的吡虫啉10％WP的混配剂对温室粉虱(Trialeurodes vaporariorum)进行了协同药效试验,吡虫啉添加量仅相当于推荐用量的6．4％～9．5％和19．1％～28．6％,试验含6个菌剂处理、2个低用量吡虫啉处理和1个清水对照,各有3个小区(7m×5m·小区^-1)重复,随机区组排列,稀释1000倍的菌液(含孢量10^7·ml^-1)和吡虫啉液于生菜移栽后第11d首次喷雾,15d后喷第二次,首次用菌前调查初始粉虱密度,用菌后每隔5d调查活虫数和死虫数,从8月20日起历时30d,结果表明,连续2次用菌有效地控制了粉虱对当季大棚生菜的危害,各菌剂处理的最终相对防效和虫口减退率均达到95％以上,极显著地高于低用量吡虫啉处理,其中,玫烟色拟青霉制剂对粉虱的控制效果一般优于球孢白僵菌制剂,且与吡虫啉的添加量呈正相关,但是,各菌剂处理间控虫效果的差异主要发生在首次用菌后第5d和10d,此后差异逐渐缩小,至第二次用菌后第10d各菌剂处理间无显著差异,本试验结果表明,两种真菌的孢子乳悬剂均可用于温室粉虱的防治,添加微量吡虫啉可增强菌剂的防效。     

Fumigant toxicity of essential oil from Tanacetum balsamita L. (Compositae) against adults and eggs of Callosobruchus maculatus F. (Coleoptera: Bruchidae)

The essential oil of Tanacetum balsamita L. was tested against Callosobruchus maculatus F. at the rates of 5.12, 7.23, 10.19, 14.36 and 20.24?μl/l?air for adults and 5.3, 8.5, 10.8, 13.7 and 17.4?μl/l?air for eggs. All experiments were conducted at 27?±?1?°C and 65?±?5% relative humidity. Mortality was counted after 24, 48 and 72?h of exposure and all adults (dead and alive) were taken out of the vials and the vials were left at the same conditions for further 35?days to assess progeny production. For mortality of eggs, unhatched eggs were counted after 7?days. The adults treated with oil were more susceptible than eggs. At highest dose (20.24?μl/l?air) mortality of adults after 72?h, received 75.2%, but this amount for egg at 17.4?μl/l?air after 72?h was 49.06%. The lowest LC₅₀ value on 72?h was observed in adults (1.96?μl/l?air). Also, the lowest LC₉₅ value on 72?h was observed in adults (42.86?μl/l?air). The percentage of reduced progeny on 72?h was 50.92% at 20.24?μl/l?air. Our results suggest that T. balsamita can be used as an alternative to synthetic insecticides but higher dose may be needed.     

B型烟粉虱与温室白粉虱不同虫态的碱性磷酸酶性质比较

为了探明B型烟粉虱Bemisia tabaci B-biotype 和温室白粉虱Trialeurodes vaporariorum体内的碱性磷酸酶(alkaline phosphatase,ALP)在两者竞争替代中所起的作用,以对硝基苯磷酸二钠 (pNPP)为底物,采用个体测定和群体测定的方法,研究比较了2种粉虱不同虫态中该酶的性质。结果表明：2种粉虱的碱性磷酸酶比活力在整个发育历期均逐渐增加,成虫期达到最大。温室白粉虱2至4龄若虫（伪蛹）期的碱性磷酸酶比活力分别是B型烟粉虱对应龄期酶比活力的2.58、2.68和3.14倍; B型烟粉虱雌雄成虫的碱性磷酸酶比活力分别是温室白粉虱雌雄成虫酶比活力的1.24和1.26倍,且2种粉虱雌虫的酶比活力显著大于其雄虫。2种粉虱2龄若虫到成虫的碱性磷酸酶最适pH均为7.8,最适温度均为47℃;在1龄若虫中均未能检测到该酶活性。测定并比较2种粉虱不同虫态碱性磷酸酶动力学特征参数的结果显示,温室白粉虱碱性磷酸酶在3、4龄若虫的亲和力以及在2, 3, 4龄若虫的酶蛋白浓度均显著大于B型烟粉虱的对应值,而在成虫期2种粉虱的亲和力、酶蛋白浓度无差异,B型烟粉虱的活化能显著小于温室白粉虱。据此推测,B型烟粉虱利用碱性磷酸酶在若虫期进行组织骨化和生长发育不如温室白粉虱,但羽化为成虫后利用其进行解毒代谢则可能强于温室白粉虱。     

Trials of Beauveria bassiana, Paecilomyces fumosoroseus and imidacloprid for management of Trialeurodes vaporariorum (Homoptera: Aleyrodidae) on greenhouse grown lettuce

Mineral oil-based emulsifiable preparations of Beauveria bassiana (Bb) and Paecilomyces fumosoroseus (Pfr) conidia were separately applied alone or together with low rates of imidacloprid 10% WP at 4.7% (Im 1), 14.0% (Im 2), and 23.3% (Im 3) of its recommended application rate, respectively, against the greenhouse whitefly, Trialeurodes vaporariorum, on lettuce grown in the greenhouse. Besides eight fungal treatments, the three low application rates of imidacloprid in the oil-based carrier and a blank control (CK) were also included as treatments of the trials conducted in 2002 and 2003. For the 12 treatments of each trial with three replicates, 1,000-fold aqueous dilutions were sprayed twice on transplanted lettuce at a 15-day interval at a rate of ∼1.43×10¹³ conidia ha^-1 for each fungal treatment or at one of the low rates of imidacloprid using a backpack hand-operated hydraulic sprayer. Based on whitefly densities, mortalities, relative efficacies and percent density declines estimated from whitefly counts made at 5-day intervals, all B. bassiana and P. fumosoroseus sprays were highly effective against T. vaporariorum compared to CK and Im 1-3 in both trials. In trial 1, the estimates of whitefly density decline and relative efficacy ranged from 44 and 72% (Bb) to 79 and 90% (Pfr+Im 2-3) on day 10 after the first spray and exceeded 94% for all fungal treatments 10 days after the second spray. Similar trends in whitefly control were also achieved in the corresponding treatments of trial 2. A more desirable and faster control resulted from fungal sprays containing more imidacloprid, but none of the three low imidacoprid rates alone suppressed the whitefly population more effectively than any fungal treatment despite a varying degree of efficacy. Moreover, P. fumosoroseus tended to be more effective against T. vaporariorum than B. bassiana when applied alone or together with the same low rate of imidacloprid but the difference in whitefly control eventually achieved was not significant between the two fungal agents. Thus, the emulsifiable preparations of both fungal agents can be considered as alternatives for whitefly management and for a slightly faster control can be applied together with imidacloprid at around 15% of its common application rate. An economic balance between the efficacy of whitefly control and the ease and cost of conidial production is needed when both fungi are incorporated into whitefly management.     

Diapause induction under greenhouse conditions in two populations of Dicyphus hesperus (Hemiptera: Miridae)

The effects of daylength on induction of reproductive diapause were investigated in two populations of Dicyphus hesperus to determine which was more suitable as a biological control in greenhouses without supplemental light. A population from British Columbia Canada (49°36' N Lat.) had a critical daylength of about 15.5 h, whereas that of a population from California, USA (35°43' N Lat.) was between 14.0 and 13.5 h. Under natural daylengths in greenhouses at 49°N Lat., females of both populations exhibited reproductive diapause at a daylength that was consistent with their respective critical daylengths. In spring, a lower proportion of both populations diapaused when exposed to diapause-inducing conditions than in autumn. Reproductive diapause of the females of the BC population was 100% in autumn, but half of those females laid eggs when held in the greenhouse for 6 weeks. A maximum of 63% of females of the California population diapaused in autumn, and most began to lay eggs after 2 weeks. The differences in response to daylength presumably reflect differences between the two localities in the reliability of the critical daylength as a predictor of conditions unsuitable for growth and reproduction. Under greenhouse conditions the California population is essentially non-diapausing, and would be the more suitable of the two populations for use as a biological control agent.     

Bioassay evaluation of the entomopathogenic fungus,Lecanicillium longisporum (Petch) Zare & Gams against egg and nymphs of Trialeurodes vaporariorum Westwood in laboratory conditions

Abstract

This study was carried out to determine the lethality of the entomopathogenic fungus, Lecanicillium longisporum on eggs, young and old nymphs of the greenhouse whitefly, Trialeurodes vaporariorum. Mortality percentage was significantly differed based on stage of T. vaporariorum and conidial concentrations of L. longisporum. Average of the infection level to insect was very low particularly in egg with only 9.81%, even with higher conidial concentrations (1×10⁷ conidia mL^-1). Whereas, it was higher in 1^st and 2^nd instar (46.56%) and 3^rd and 4^th instars (37.21%). Three parameters were assessed with T. vaporariorum eggs, namely; egg infection, egg hatchability and crawlers emergence. Egg mortality percentages averaged 3.56, 7.14, 9.64, 16.42 and 20.35% with fungal concentrations of 1×10³, 1×10⁴, 1×10⁵, 1×10⁶ and 1×10⁷ conidia mL^-1, respectively. Daily infection percentages were varied depend upon the conidia concentration where the highest infection rate of eggs was occurred with 1×10⁷. Egg hatch was very high and the mortality among the emerged crawlers was neglectable compared with the control. Efficiency of L. longisporum on whitefly nymphs also was varied based on the insect instar and fungal concentration. Mortality percentages were obviously higher in young nymphs (1^st and 2^nd instars) than in older ones (3^rd and 4^th instars). The results indicated that nymphs were highly susceptible to fungal treatment compared with eggs.     

Effect of environmental factors on the flight activity of Trialeurodes vaporariorum (Westwood) under greenhouse conditions

The flight activity of the greenhouse whitefly Trialeurodes vaporariorum (Westwood) was monitored over a 3‐year period in greenhouses containing tomato and zucchini crops. The environmental factors affecting its flight activity and dispersal were analyzed. Among the climatic variables, temperature had a positive impact on T. vaporariorum flight, whereas relative humidity had only a weak effect. More flights were made during the morning and afternoon, with fewer flights occurring when the temperature was above 25°C in greenhouses containing zucchini or above 30°C in those containing tomato; no flights were recorded when the temperature was 12.30°C in either setting. Flight typology, classified as short, long or dispersal, and covering a few centimeters to more than 2–3 m, was influenced by the vegetative condition of the plants. As the plants aged and declined in condition, the number of short flights decreased, whereas the number of long and dispersal flights increased. Based on these results, we can conclude that the dispersal of T. vaporariorum in greenhouses containing either tomato or zucchini crops is generally influenced by environmental factors, which also affect the type of flight, with a trade‐off between short and long dispersal flights. However, adult dispersal is driven not only by temperature, but also by other factors, such as conspecific density and time of the day. Therefore, producers must consider such factors when aiming to reduce the dispersal of pest insects within greenhouses and, thus, to maintain the productivity of their crops.     

甘蓝与黄瓜寄主上B型烟粉虱和温室白粉虱蜜露糖分、氨基酸和挥发物组分的比较分析

粉虱蜜露是粉虱寄生性天敌搜索寄主的主要利它素源。应用离子色谱分别对甘蓝与黄瓜上B型烟粉虱(Bemisia tabaci B-biotype)蜜露以及黄瓜上温室白粉虱Trialeurodes vaporariorum蜜露的接触性利它素糖和氨基酸组分和含量进行了比较研究。结果表明：2种粉虱在不同寄主植物上的蜜露均富含糖和氨基酸,其中糖含量占绝对优势,甘蓝上B型烟粉虱蜜露、黄瓜上B型烟粉虱蜜露和黄瓜上温室白粉虱蜜露中的糖含量分别是相应氨基酸含量的42.5、2.6和5.4倍,其中糖类物质中又以寡糖含量占绝对优势,分别占89.3%、81.7%和88.2%。不同寄主植物和粉虱种类显著影响蜜露中糖和氨基酸的组成和含量。其中,甘蓝上B型烟粉虱蜜露中的寡糖以二糖占优势,占97.3%;二糖中又以蔗糖异构糖和松二糖占优势,分别占52.7%和35.4%。黄瓜上B型烟粉虱蜜露和温室白粉虱蜜露寡糖中以三糖和四糖占优势,分别占73.1%和85.4%;优势糖水苏（四）糖和松三糖分别占40.3%和 26.2%及49.9%和27.0%。甘蓝上B型烟粉虱蜜露中氨基酸以丙氨酸占优势,含量为66.5%;而黄瓜上B型烟粉虱及温室白粉虱蜜露中氨基酸以甘氨酸含量最高,分别占氨基酸总量的38.2%和51.7%。应用GC-MS对甘蓝上B型烟粉虱蜜露和黄瓜上温室白粉虱蜜露挥发物组分的鉴定结果显示,两种粉虱蜜露中共同含有的主要挥发物为邻苯二甲酸二（2-乙基）己酯。