Competition for light between velvetleaf (Abutilon theophrasti) and soybean (Glycine max)

We examined factors affecting conversion of light into dry matter of velvetleaf (Abutilon theophrasti) and soybean (Glycine max) grown in a replacement series near Ames, Iowa, U.S.A. in 1986 and 1987. Velvetleaf was taller than soybean over most of the growing season and had more branches, especially at the top of the canopy. Velvetleaf had greater light interception than soybean in the upper part of the canopy, particularly early and late in the day, although total light interception by canopies of the two species was similar on most sample dates. Velvetleaf had higher light utilization efficiency, or conversion of intercepted light into dry matter, in the middle and later part of the growing season. This combination of traits appears to give velvetleaf an advantage over soybean in competition for light.     

南亚实蝇成虫空间分布型及抽样技术

南亚实蝇Zeugodacus tau(Walker)是瓜果蔬菜上重要的检疫性害虫,常导致严重的经济损失。本文旨在明确其在主要寄主作物(丝瓜、“苦瓜-桂花”系统)上的空间格局,并根据最适理论抽样数制定了采样方案,以便为该虫管理决策提供科学依据。于2020年7月和9月分别在立架栽培的丝瓜地和“苦瓜-桂花”系统采用黄板诱捕实蝇类害虫,用非参数两独立样本t测验分析不同生境南亚实蝇雌、雄成虫种群密度的差异显著性,用2个常用的聚集度指标(C和k)和2个回归模型(Taylor幂回归模型和Iwao的m~*-m回归模型)分别分析雌虫、雄虫和“雌虫+雄虫”的空间格局。共诱集实蝇成虫3 542头,“苦瓜-桂花”系统只诱集到南亚实蝇,丝瓜地诱集到4种果实蝇,其中南亚实蝇占97.2%,为优势种。桂花树上的南亚实蝇雌虫种群密度显著高于苦瓜地(Z=-2.932,P=0.003),为后者的1.87倍;丝瓜地样地Ⅱ中的雌虫种群密度显著大于样地Ⅰ(Z=-7.160,P<0.001),为后者的3.13倍。回归分析表明,对雌虫,Taylor的b和Iwao的β与1无显著差异(t_c...     

Biology and integrated pest management for the banana weevil Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae)

The banana weevil Cosmopolites sordidus (Germar) is the most important insect pest of bananas and plantains (Musa spp.). The larvae bore in the corm, reducing nutrient uptake and weakening the stability of the plant. Attack in newly planted banana stands can lead to crop failure. In established fields, weevil damage can result in reduced bunch weights, mat die-out and shortened stand life. Damage and yield losses tend to increase with time. This paper reviews the research on the taxonomy, distribution, biology, pest status, sampling methods, and integrated pest management (IPM) of banana weevil. Salient features of the weevil's biology include nocturnal activity, long life span, limited mobility, low fecundity, and slow population growth. The adults are free living and most often associated with banana mats and cut residues. They are attracted to their hosts by volatiles, especially following damage to the plant corm. Males produce an aggregation pheromone that is attractive to both sexes. Eggs are laid in the corm or lower pseudostem. The immature stages are all passed within the host plant, mostly in the corm. The weevil's biology creates sampling problems and makes its control difficult. Most commonly, weevils are monitored by trapping adults, mark and recapture methods and damage assessment to harvested or dead plants. Weevil pest status and control options reflect the type of banana being grown and the production system. Plantains and highland bananas are more susceptible to the weevil than dessert or brewing bananas. Banana production systems range from kitchen gardens and small, low-input stands to large-scale export plantations. IPM options for banana weevils include habitat management (cultural controls), biological control, host plant resistance, botanicals, and (in some cases) chemical control. Cultural controls have been widely recommended but data demonstrating their efficacy are limited. The most important are clean planting material in new stands, crop sanitation (especially destruction of residues), agronomic methods to improve plant vigour and tolerance to weevil attack and, possibly, trapping. Tissue culture plantlets, where available, assure the farmer with weevil-free material. Suckers may be cleaned by paring, hot water treatment and/or the applications of entomopathogens, neem, or pesticides. None of these methods assure elimination of weevils. Adult weevils may also invade from nearby plantations. As a result, the benefits of clean planting material may be limited to a few crop cycles. Field surveys suggest that reduced weevil populations may be associated with high levels of crop sanitation, yet definitive studies on residue management and weevil pest status are wanting. Trapping of adult weevils with pseudostem or corm traps can reduce weevil populations, but material and labour requirements may be beyond the resources of many farmers. The use of enhanced trapping with pheromones and kairomones is currently under study. A combination of clean planting material, sanitation, and trapping is likely to provide at least partial control of banana weevil.Classical biological control of banana weevil, using natural enemies from Asia, has so far been unsuccessful. Most known arthropod natural enemies are opportunistic, generalist predators with limited efficacy. Myrmicine ants have been reported to help control the weevil in Cuba, but their effects elsewhere are unknown. Microbial control, using entomopathogenic fungi and nematodes tend to be more promising. Effective strains of microbial agents are known but economic mass production and delivery systems need further development.     

大豆蚜阶段特异性经济阈值的制定

为制定大豆蚜Aphis glycines阶段特异性经济阈值,于2015—2018年连续4年开展田间试验,通过定点、定株调查和产量测定,运用回归分析法研究大豆4个特定生长阶段下不同密度大豆蚜侵染对其产量损失的影响。结果表明,在大豆4叶期—初花期阶段,大豆蚜侵染的累计蚜日及其种群增长率均最大,分别达到40 900头·日和0.184,大豆产量损失率也最高,达到了60.96%。大豆蚜的侵染密度与产量损失率在大豆出苗期—4叶期和4叶期—初花期阶段使用线性模型拟合的优度最高,在初花期—初荚期和初荚期—鼓粒期阶段使用对数曲线模型拟合的优度最高,并构建了各阶段的回归方程。基于反映市场价值和潜在产量变化的动态经济允许损害水平,得到大豆出苗期—4叶期、4叶期—初花期、初花期—初荚期和初荚期—鼓粒期阶段的平均蚜量阈值分别为79、227、323和460头/株;依据线性相关性转换得到更利于实际应用的阈值指标——有蚜株率和卷叶株率,如果提前3 d进行防治,则出苗期—4叶期阶段的有蚜株率阈值为17.88%,4叶期—初花期、初花期—初荚期和初荚期—鼓粒期阶段的卷叶株率阈值分别为4.78%、7.88%和12.59%。表明大豆蚜阶梯式的阶段特异性经济阈值随大豆生育期的推进而放宽;且提前3 d的准备时间便于种植者进行早期决策,从而有针对性地选择防治大豆蚜的作物生育期。     

Immunofluorescence Colony-staining (IFC) for Detection and Quantification of Ralstonia (Pseudomonas) solanacearum Biovar 2 (Race 3) in Soil and Verification of Positive Results by PCR and Dilution Plating

A procedure was developed for specific and sensitive quantitative detection of Ralstonia (Pseudomonas) solanacearum biovar 2 (race 3) in soil. It is based on immunofluorescence colony-staining (IFC) followed by confirmation of the identity of fluorescent colonies by PCR-amplification or dilution plating on a semi-selective medium, SMSA. Addition of sucrose and the antibiotics cycloheximide and crystal violet to the non-selective trypticase soy broth agar resulted in increased colony size and staining intensity of R. solanacearum in IFC. Verification of IFC-results by picking cells from IFC-positive colonies followed by dilution plating of the suspended cells on SMSA was highly efficient. The success rate was 92% and 96% with spiked and naturally contaminated soils respectively. Several other bacterial species which cross-reacted with polyclonal antibodies in IFC also grew on SMSA and were difficult to distinguish from R. solanacearum, thereby necessitating confirmation of the results. Rapid verification of IFC-positive results directly by PCR-amplification with primers D2/B specific to division 2 of R. solanacearum had a success rate of 86% and 96% with spiked and naturally contaminated soil samples, respectively. Primers D2/B reacted with all R. solanacearum division 2 strains, and strains of R. syzygii and the banana blood disease bacterium, but not with saprophytic bacteria cross-reacting in IFC with R. solanacearum antibodies. In comparative tests, IFC was able to detect consistently ca. 100 cfu g^–1 of soil, a detection level similar to that found with direct plating on SMSA, but less laboriously, whereas detection level with a bioassay on tomato plants was only 10⁴–10⁵ cfu g^–1 of soil.     

Base-catalysed hydrolysis of (E)- and (Z)-mevinphos

The rates at which (E)- and (Z)-mevinphos are hydrolysed in aqueous solutions in the pH range 8.7–11.5, and in the temperature range 30–50°C, have been measured. The overall activation parameters have been calculated, and equations to allow calculation of the rates in any basic conditions are given. The complicated routes by which (E)- and (Z)-mevinphos are hydrolysed to simple molecules have been deduced. The rates for the individual steps in each route have been either measured experimentally, or have been calculated through analogue simulation of all the reactions, by matching the calculated to the observed ultraviolet spectral changes during hydrolysis. It is proposed that (Z)-2-carboxyl-1-methylvinyl dimethyl phosphate is not observed as a hydrolysis product of (Z)-mevinphos because it decomposes by an extremely fast intramolecular reaction. The reasons for the greater lability of (E)-mevinphos are also discussed.     

A greenhouse test for screening sugar-beet (Beta vulgaris) for resistance to beet necrotic yellow vein virus (BNYVV)

Small differences in activity between batches of purified beet necrotic yellow vein virus (BNYVV) were observed in ELISA. A four-parameter modelled dose-response curve of purified BNYVV was used for the conversion of ELISA values to virus concentrations. Seedlings of the susceptible cultivar Regina and the partially resistant cultivars Nymphe and Rima were tested for resistance to BNYVV in a mixture of sand and infested soil. Plants were grown in a green-house with low nutrient supply and at temperatures below the optimum of both the vectorPolymyxa betae and BNYVV. Root systems were small and consisted mainly of lateral roots. Significant differences in average virus concentrations were found between cultivars, both when using the complete root systems and when using either the top or the bottom part of the root systems. Average virus concentrations in Regina were always significantly higher than in Rima and higher than in Nymphe on all occasions except one (P<0.05). Differences between Nymphe and Rima were less evident. Variation between plants was greatest within Rima. The test described in this paper can be used for the discrimination of different cultivars and for the identification of individual plants with resistance to BNYVV.     

Comparative biology of Mallada desjardinsi (navas) and Chrysoperla congrua (walker) (Neuroptera: Chrysopidae), predators of Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) and aphis gossypii (glover) (Homoptera: Aphididae) on cotton in eastern Tanzania

The developmental biology of Mallada desjardinsi (Navas) and Chrysoperla congrua (Walker) on the American bollworm, Helicoverpa armigera and the cotton aphid, Aphis gossypii was studied in the laboratory at 28–32°C. Total larva! periods of M. desjardinsi and C. congrua on H. armigera eggs were 14.4 and 14.8 days respectively. However, when reared on A. gossypii larval periods of M. desjardinsi and C. congrua were 14.9 and 13.5 days respectively. When reared on H. armigera 52.9% and 25% respectively of third instars of M. desjardinsis and C. congrua sp. died before pupation. However, when reared on A. gossypii 82.6% and 46.9% respectively of third instars of M. desjardinsi and C. congrua died before pupation. Thus, H. armigera eggs and A. gossypii nymphs were both adequate but not optimal diets for chrysopid larval development. The number of prey consumed by M. desjardinsi and C. congrua increased with instar. Total larval consumption of H. armigera by M. desjardinsi and C. congrua was determined to be 135.5 and 169.8 eggs respectively. However, total larval consumption of A. gossypii by M. desjardinsi and C. congrua was found to be 189.0 and 171.8 nymphs respectively. Because of its longer larval period, and higher consumption of A. gossypii, M. desjardinsi would be better suited for use against A. gossypii than C. congrua. In contrast, C. congrua whose consumption of H. armigera was higher than that of M. desjardinsi although their larval periods were similar, would appear promising for control of H. armigera.     

检疫性害虫南亚果实蝇生物学及控制技术

南亚果实蝇[Bactrocera(Zeugodacus)tau(Walker)]是黄瓜、南瓜、丝瓜、冬瓜和苦瓜等多种果蔬作物上的一种重要检疫性害虫。近年来在我国多个省市发生危害,发生程度呈加重和扩大蔓延的趋势,对瓜果作物造成了严重的经济损失。本文概述了南亚果实蝇的发生危害规律、生物学特性,提出了加强植物检疫、农业防治、诱集灭虫、雄性不育技术和保护天敌等防治措施。     

20%氰戊菊酯水乳剂防治菜青虫田间药效试验

为验证20%氰戊菊酯水乳剂对甘蓝菜青虫的防治效果,进行了田间药效试验。试验结果表明,20%氰戊菊酯水乳剂对菜青虫有较好的防治效果,适宜剂量为6～8ga·i/667m2,持效期为7d以上。     

谷斑皮蠹与黑斑皮蠹的分子鉴定

本文首次报道了可用于谷斑皮蠹(Trogoderma granarium)和黑斑皮蠹(Trogoderma glabrum)种间鉴定的线粒体CO Ⅰ基因部分标记序列(883bp),两条序列在GenBank数据库的登录号分别为FJ589736和FJ589737.     

南瓜实蝇的发育起点温度和有效积温

在18、22、26、30和34℃5种恒温条件下,测定了南瓜实蝇[Bactraera tau(Walker)]各虫态发育起点温度及有效积温。结果表明,南瓜实蝇卵、幼虫、蛹、产卵前期和全世代的发育起点温度分别为(13.10±2.35)、(9.86±1.47)、(12.87±1.36)、(9.66±0.91)和(9.54±0.89)℃,有效积温分别为(26.30±4.57)、(134.04±11.38)、(149.92±36.92)、(157.56±43.64)和(542.25±24.79)日·度。     

Field performance of Lynfield and McPhail traps for monitoring male and female sterile Bactrocera tryoni (Froggatt) and wild Dacus newmani (Perkins)

BACKGROUND: McPhail traps, baited with protein food lure, are used worldwide for surveillance of many species of fruit flies. Queensland fruit fly (Qfly) Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) is a native Australian fruit fly and normally monitored using Lynfield traps baited with cuelure. On some occasions, McPhail traps with wet food lures are deployed to detect female flies or to find the incursion epicentre. This paper reviews field results on the merits of Lynfield and McPhail traps for detection of male and female Qfly. RESULTS: Following release of equal numbers of sterile males and females, Lynfield traps baited with cuelure captured more Qfly males than protein autolysate or orange concentrate in McPhail traps. Significantly more male than female Qfly were captured in McPhail traps baited with protein autolysate or orange. There was no significant difference between orange concentrate lure and protein autolysate lure in attracting either males or females. Another Australian native fruit fly, Dacus newmani (Perkins), was attracted to cuelure in Lynfield traps but not to either lure in McPhail traps. CONCLUSIONS: The data obtained run counter to the reputation of McPhail traps baited with protein autolysate or orange concentrate as a specialist lure/trap combination for female Qfly. Copyright © 2010 Society of Chemical Industry     

Evaluation of medium treatments for management of Frankliniella occidentalis (Thripidae: Thysanoptera) and Bradysia coprophila (Diptera: Sciaridae)

Two greenhouse experiments, each comprising two trials, were conducted to evaluate medium drenches of insect growth regulators and conventional insecticides to reduce emergence of adult western flower thrips, Frankliniella occidentalis (Pergande), and fungus gnats, Bradysia coprophila (Lintner) from the medium. In the insect growth regulator trials, diflubenzuron and pyriproxyfen provided the greatest reduction in thrips emergence, and fenoxycarb, pyriproxyfen and azadirachtin resulted in the most significant reduction of fungus gnat emergence. Treatments with the contact insecticides, methiocarb and chlorpyrifos, resulted in the greatest reduction of thrips and fungus gnat populations. These data suggest that fungus gnats are susceptible to many compounds used in commercial greenhouse production. Even though medium drenches are not currently used for thrips management, drenches with diflubenzuron, pyriproxyfen, methiocarb and chlorpyrifos could aid in reducing thrips populations in greenhouse management programs. © 2001 Society of Chemical Industry     

菊方翅网蝽雌雄成虫图像识别技术的初步研究

菊方翅网蝽主要为害菊科植物,是特种经济作物菊芋的潜在性害虫,对此害虫的形态识别和种群动态预测非常重要。昆虫几何形态特征的提取和分析是进行其自动识别、远程鉴定、种群监测和预测预报的基础。本文利用图像采集与处理技术,通过BugShape软件对其外部几何形态特征进行了自动和手动获取与分析。结果表明,菊方翅网蝽周长和紧凑度两个参数在不同分辨率下差异显著,雌虫球状性在不同分辨率下也差异显著。雌雄之间周长、长轴长度和短轴长度差异不显著,而偏心率、紧凑度、球状性、叶状性和圆形度差异均达到显著水平。雌雄个体的原始判别正确率为92%~93%,交叉判别正确率为91%~93%。使用所有10个参数进行判别分析时,判别的正确率与分辨率呈正相关关系。手动测量结果表明,菊方翅网蝽雌雄成虫体长分别为(1.86±0.07)mm和(1.80±0.07)mm,中胸宽度分别为(0.73±0.02)mm和(0.69±0.03)mm,腹部宽度分别为(1.04±0.05)mm和(0.84±0.07)mm。利用手动测量数据进行雌雄个体判别分析的正确率达到98%~99%。     

红彩瑞猎蝽微胶囊人工饲料饲养效果评价

为开展红彩瑞猎蝽的人工规模化繁育, 研制了一种以自然猎物血淋巴为主, 烟草汁液为辅的微胶囊人工饲料, 并对其性状和饲养效果进行了评价, 以面包虫饲养的猎蝽作对照。结果表明, 人工饲料微胶囊成品率73.17%, 含水率92.35%, 综合感官评定86.8分。取食微胶囊的红彩瑞猎蝽若虫发育历期均显著长于对照, 若虫的存活率、体重均显著低于对照, 随龄期的增长与对照差异的显著性逐渐减小;处理组成虫获得率16.7%, 对照68.9%;成虫产卵前期显著长于对照, 但产卵量和卵孵化率无显著差异。猎物斜纹夜蛾幼虫密度为8头/皿时, 微胶囊饲养的红彩瑞猎蝽的捕食量显著低于对照, 但在较低猎物密度时无显著差异。此种人工饲料能基本满足红彩瑞猎蝽的生长发育, 可在一定程度上替代面包虫。