联肼·乙螨唑对蔬菜优势叶螨产卵发育的影响及其田间防效

为明确新型复配杀螨剂联肼·乙螨唑对目前蔬菜田常发生的2种优势叶螨二斑叶螨Tetranychus urticae和截形叶螨T. truncatus的杀螨活性,于室内采用离体叶碟法测定其对这2种叶螨产卵及发育的影响,于室外采用活体植株评价该药剂对2种叶螨的田间防效。结果表明,经复配杀螨剂联肼·乙螨唑及其单剂处理2种叶螨雌成螨24 h后,死亡率为20.50%～54.98%,均显著高于清水对照;联肼·乙螨唑处理较清水对照显著降低了2种叶螨卵发育至若螨期的比率,联肼·乙螨唑处理后二斑叶螨和截形叶螨的若螨率分别为4.91%和1.63%。田间试验中联肼·乙螨唑对2种叶螨具有一定的速效性,药后3 d对二斑叶螨和截形叶螨的防效分别达95.74%和89.83%,药后7 d防效分别为98.03%和99.44%,显示了优良的防控效果及持效性。表明复配杀螨剂联肼·乙螨唑可用于田间蔬菜优势叶螨种群的高效防控。     

Effects of azadirachtin on Tetranychus urticae (Acari: Tetranychidae) and its compatibility with predatory mites (Acari: Phytoseiidae) on strawberry

BACKGROUND: The spider mite, Tetranychus urticae, is the major strawberry pest in Brazil. The main strategies for its control comprise synthetic acaricides and predatory mites. The recent register of a commercial formula of azadirachtin (Azamax^® 12 g L^?1) can be viable for control of T. urticae. In this work, the effects of azadirachtin on T. urticae and its compatibility with predatory mites Neoseiulus californicus and Phytoseiulus macropilis in the strawberry crop were evaluated. RESULTS: Azadirachtin was efficient against T. urticae, with a mortality rate similar to that of abamectin. In addition, the azadirachtin showed lower biological persistence (7 days) than abamectin (21 days). Azadirachtin did not cause significant mortality of adult predatory mites (N. californicus and P. macropilis), but it did reduce fecundity by 50%. However, egg viability of the azadirachtin treatments was similar to that of the control (>80% viability). The use of azadirachtin and predatory mites is a valuable tool for controlling T. urticae in strawberry crop. CONCLUSIONS: Azadirachtin provided effective control of T. urticae and is compatible with the predatory mites N. californicus and P. macropilis. It is an excellent tool to be incorporated into integrated pest management for strawberry crop in Brazil. Copyright © 2012 Society of Chemical Industry     

Spiromesifen toxicity to the spider mite <Emphasis Type="Italic">Tetranychus urticae</Emphasis> and selectivity to the predator <Emphasis Type="Italic">Neoseiulus californicus</Emphasis>

Tetranychus urticae Koch (Acari: Tetranychidae) is a major pest of several agricultural crops and Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) is an important natural enemy of this pest mite. The objective of the study was to evaluate the effect of spiromesifen on the development and reproduction of T. urticae, and to assess the influence of spiromesifen and other acaricides on the population growth rates of the spider mite and its predator, N. californicus. Toxicity tests with spiromesifen at different life stages of T. urticae indicated that eggs less than 72 h old were more sensitive than other development stages. The oviposition rate of T. urticae was significantly affected by spiromesifen. Experiments on the effects of spiromesifen on the growth rates of T. urticae and N. californicus indicated that spiromesifen is innocuous to the predaceous mite but highly toxic to the spider mite, leading to population suppression in 10 days. Fenpropathrin, acephate and neem oil were not harmful to N. californicus, but were not so efficient as spiromesifen in controlling T. urticae, and had significantly less influence on the population growth rates of the spider mite. Among these three products, only neem oil caused significant reduction in the growth rate of T. urticae. Chlorfenapyr, abamectin, milbemectin and diafenthiuron significantly affected the population growth rates of T. urticae and N. californicus. Spiromesifen was the most promising acaricide for managing the two-spotted spider mite, when used in combination with N. californicus.     

Host plant preference of aphids, thrips and spider mites on GNA-expressing and control potatoes

The effect of snowdrop lectin (Galanthus nivalis agglutinin: GNA) expression on host-plant preference was examined with a two-choice disc test. Discrimination between a transgenic potato [Solanum tuberosum (Solanaceae)] capable of synthesizing GNA, and an isogenic cultivar, was studied under laboratory conditions using the glasshouse potato aphidAulacorthum solani (Hemiptera: Aphididae), the onion thripThrips tabaci (Thysanoptera: Thripidae), and the two-spotted spider miteTetranychus urticae (Acari: Tetranychidae). Adults of these species were placed individually on leaf discs (one half transgenic and one half control) and observed 1, 24, 48, 72 and 96 h after release, at which times also the distributions ofA. solani nymphs andT. urticae eggs on the discs were recorded. Aphids were found more frequently on control leaves at all observation periods, with the highest bias observed at 72 h (only 35.9% of all aphids were found on the GNA halves). Similarly, more aphid nymphs (57.6% of the total) were found on isogenic half-discs. The percentage of thrips found on GNA halves ranged from 36.8% to 48.4%, with significant control-potato bias at the first three observations. Contrary to this, the proportion ofT. urticae females found on GNA halves was significantly lower than the expected proportion (0.5) at 72 and 96 h, with a minimum of 34.0% on GNA. The distribution of spider mite eggs reflected the observed biased distribution of females (only 34.1% of all eggs were laid on GNA half-discs). These results indicate that potatoes expressing GNA for resistance against aphids are less preferred than an isogenic cultivar by all three tested species under a choice test condition using excised leaves.     

Daily consumption and predation rate of different<Emphasis Type="Italic">Stethorus punctillum</Emphasis> instars feeding on<Emphasis Type="Italic">Tetranychus urticae</Emphasis>

Laboratory experiments were conducted to evaluate the prey stage preference and the daily consumption of each stage of the coccinellid predatorStethorus punctillum Weise (Coleoptera: Coccinellidae) feeding on the two-spotted spider miteTetranychus urticae (Koch) (Acari: Tetranychidae). Groups of different life stages of the prey were offered (eggs, larvae, nymphs and adults). The prey preference varied with the stage ofS. punctillum. First larval instars had no significant preference among theT. urticae stages offered. Second larval instars consumed significantly more spider mite larvae in comparison with nymphs. In contrast, third larval instars indicated a strong preference for mite eggs. Significantly fewerT. urticae larvae were consumed by the fourth larval instars ofS. punctillum, in comparison with the three other mite stages. Finally, adult predators consumed significantly more mite eggs than the other stages offered. This preferential trend was similar for all adults tested, whether during the pre-oviposition or the oviposition period. http://www.phytoparasitica.org posting Feb. 17, 2004.     

东方钝绥螨生物学及食量研究

东方钝绥螨在昌黎地区每年大约发生23代左右。平均卵期1.8天,幼虫期0.7天、第一若虫期1.0天、第二若虫期1.5天、产卵前期4.6天、产卵期15.2天、雌成螨期20.5天、雄成螨期15.6天、生命周期为25.5天。平均日产卵量1.5粒,总卵量16粒。雌成螨日捕食山楂叶螨卵3粒及若螨0.46头,总捕食量为卵91粒,若螨43头及成山楂叶螨14头,对苹果全爪螨捕食量3.4头(雌成螨)。     

Acaricide toxicity and resistance in larvae of different strains of Tetranychus urticae and Panonychus ulmi (Acari: Tetranychidae)

The toxicities of eight structurally different acaricidal compounds to six‐legged larvae (first motile stage) of three laboratory strains of the two‐spotted spider mite, Tetranychus urticae, and the European red mite, Panonychus ulmi, were evaluated following spray application. The larvae of five field‐derived strains of T urticae originating from France, Italy, Brazil, California and Florida were also tested for their susceptibilities to discriminating concentrations of several acaricides resulting in 95% mortality when applied to the organophosphate‐resistant laboratory reference strain WI. The spray bioassay used was robust and gave repeatable results with a wide range of acaricidal compounds, irrespective of their mode of action (ovo‐larvicides or primarily acting on motile life stages). Compounds tested were abamectin, azocyclotin, chlorpyrifos, clofentezine, deltamethrin, fenpyroximate, hexythiazox and pyridaben. Larvae of one of the laboratory strains of T urticae, AK, originally collected in Japan in 1996 and maintained without further selection pressure, exhibited 2000‐ and >4000‐fold resistance to the mitochondrial electron transport inhibitors pyridaben and fenpyroximate, respectively. Another strain of T urticae, AU, obtained from Australia and maintained in the laboratory under selection with hexythiazox and clofentezine since 1987 showed >770‐ and >1000‐fold resistance to clofentezine and hexythiazox, respectively. The same resistance pattern was observed against larvae of a laboratory strain of P ulmi, CE, also selected with hexythiazox. Larvae of one of the field‐derived strains of T urticae, BR, showed a lower susceptibility to a number of compounds, whilst the others were susceptible to all compounds except the organophosphates. © 2001 Society of Chemical Industry     

甜玉米与木薯间套作对二斑叶螨的生态调控效果

为生态调控我国木薯主产区主要外来入侵害虫二斑叶螨Tetranychus urticae,以甜玉米YT29和食用木薯品种SC9 （抗虫）及工业原料木薯品种SC205 （感虫）为供试材料,系统开展甜玉米与这2种木薯间套种对二斑叶螨调控效果的研究。结果表明,二斑叶螨对SC9表现出非适宜性,而对YT29和SC205表现出适宜性。取食SC9的二斑叶螨各虫态发育历期均显著长于取食YT29和SC205的,幼螨-后若螨死亡率显著高于取食YT29和SC205的,雌、雄成螨寿命显著短于取食YT29和SC205的,单雌产卵量、卵孵化率和雌性百分率均显著低于取食YT29和SC205的,但取食YT29和取食SC205的二斑叶螨的发育和繁殖之间无显著差异。4/YT29-2/SC9间套作模式对二斑叶螨的生态调控效果最好,不仅3年螨害指数显著低于SC9单作、 SC205单作及2/YT29-2/SC205间套作模式,而且其3年平均产量达39.1 t/hm²,显著高于SC9单作 （32.1 t/hm²）、 4/YT29-2/SC205间套作模式（20.5 t/hm²）和SC205单作（12.0 t/hm²）的平均产量。表明甜玉米与抗虫木薯品种间套作模式具有调控虫害、增产的作用,可以在我国木薯种植区大面积推广应用。     

Biology and seasonal abundance of the two-spotted spider mite, Tetranychus urticae, on orchids and rose

Biology of the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) was studied on five orchids and one rose species under laboratory conditions. The duration of developmental stages of this mite was the shortest on rose (7.17 ± 0.20 days) followed by Cymbidium (10.49 ± 1.50 days), Oncidium (11.60 ± 1.32 days), Dendrobium (12.67 ± 0.21 days), Phalaenopsis (14.47 ± 1.21 days) and Coelogyne (17.10 ± 1.29 days). The number of eggs/female laid was maximum on rose, whereas the minimum was on Phalaenopsis under the most suitable temperature (26 ± 2°C) and relative humidity (65 ± 5%) conditions. The five orchid farms (three conventionally sprayed and two unsprayed) in the northeastern region of India were surveyed during 2009 and 2010 for mite incidence. Twenty-three species and 11 hybrids of orchids were encountered as the most preferred host, 12 species as moderately preferred, and 28 species and one hybrid were found to be the least preferred orchid host for T. urticae. The mite’s incidence was recorded on orchids all year round, indicative of overlapping generations; however, two distinct population peaks were recorded during April and May. Subsequently its population declined at the start of the rainy season and remained at extremely low levels in the winter. Maximum and minimum temperatures had a significant positive correlation with mite incidence; daylight had a non-significant positive correlation; and rainfall and relative humidity had non-significant negative correlations with mite incidence. The results are discussed in relation to the most susceptible stage on orchids and suitable management practices for the two-spotted spider mite in India.     

Greenhouse and field‐based studies on the distribution of dimethoate in cotton and its effect on Tetranychus urticae by drip irrigation

BACKGROUND

The two‐spotted spider mite, Tetranychus urticae Koch is an important pest of cotton. We investigated the efficacy of dimethoate in controlling T. urticae by drip irrigation. Greenhouse and field experiments were carried out to determine the efficacy of dimethoate to T. urticae and the absorption and distribution of dimethoate in cotton.

RESULTS

Greenhouse results showed that cotton leaves received higher amounts of dimethoate compared with cotton roots and stems, with higher amounts in young leaves compared with old leaves and cotyledon having the lowest amounts among leaves. Field results showed the efficacy of dimethoate to T. urticae by drip irrigation varied by volume of dripping water, soil pH and dimethoate dosage. Dimethoate applied at 3.00 kg ha^–1 with 200 m³ ha^–1 water at weak acidic soil pH (5.70–6.70) through drip irrigation can obtain satisfactory control efficacy (81.49%, 7 days) to T. urticae, without negatively impacting on its natural enemy Neoseiulus cucumeris. The residue of dimethoate in all cotton seed samples were not detectable.

CONCLUSIONS

These results demonstrate the effectiveness of applying dimethoate by drip irrigation for control of T. urticae on cotton. This knowledge could aid in the applicability of dimethoate by drip irrigation for field management of T. urticae populations. © 2017 Society of Chemical Industry     

用杂交方法鉴定我国三种常见叶螨

本文报道通过杂交试验,连代隔离饲养观察和阳具端锤的形状区别将北京花卉上发现的绿色种叶螨、红色种叶螨和菜豆上发现的红色种叶螨作了鉴定。绿色种与两红色种之间均存在着生殖隔离,杂交产生不育后代或不能交配,因此它们是各自独立的种。绿色叶螨应是二斑叶螨(Tetranychus urticae),连代隔离饲养证明雌成螨始终体呈绿色(滞育型除外),其遗传性是稳定的,这可以作为二斑叶螨和其近似种相区别的直观特征。从阳具端锤的形状差别可以区分两种红色螨分别是硃砂叶螨(T.cinnabarinus)(采自花卉)和截形叶螨(T.truncatus)(采自菜豆)。据此,作者对国内目前通行的有关棉叶螨(T.urticae)和红叶螨(T.cinnabarinus)的学名和中文名称的混乱问题,进行了讨论。认为棉叶螨不是T.urticae,红叶螨不一定全是T.cinnabarinus。     

吉林省截形叶螨与二斑叶螨卵的发育起点温度和有效积温

在自动控制温度和光照长度的实验室内 ,采用直线回归法对截形叶螨与二斑叶螨卵的发育起点温度和有效积温进行了研究和分析 ,结果表明:在18～30℃范围内 ,截形叶螨与二斑叶螨的发育起点温度分别是14.86℃和10.78℃ ;有效积温分别是48.84、76.45日度。当温度在发育起点温度至22℃范围内二斑叶螨卵的发育速率大于截形叶螨 ,而当温度高于22℃时截形叶螨卵的发育速率大于二斑叶螨     

Compatibility of spinosad with predaceous mites (Acari) used to control Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)

BACKGROUND: Spinosad is a biopesticide widely used for control of Frankliniella occidentalis (Pergande). It is reported to be non‐toxic to several predatory mite species used for the biological control of thrips. Predatory mites Typhlodromips montdorensis (Schicha), Neoseiulus cucumeris (Oudemans) and Hypoaspis miles (Berlese) have been used for control of F. occidentalis. This study investigated the impact of direct and residual toxicity of spinosad on F. occidentalis and predatory mites. The repellency of spinosad residues to these predatory mites was also investigated. RESULTS: Direct contact to spinosad effectively reduced the number of F. occidentalis adults and larvae, causing > 96% mortality. Spinosad residues aged 2–96 h were also toxic to F. occidentalis. Direct exposure to spinosad resulted in > 90% mortality of all three mite species. Thresholds for the residual toxicity (contact) of spinosad (LT₂₅) were estimated as 4.2, 3.2 and 5.8 days for T. montdorensis, N. cucumeris and H. miles respectively. When mites were simultaneously exposed to spinosad residues and fed spinosad‐intoxicated thrips larvae, toxicity increased. Residual thresholds were re‐estimated as 5.4, 3.9 and 6.1 days for T. montdorensis, N. cucumeris and H. miles respectively. Residues aged 2–48 h repelled T. montdorensis and H. miles, and residues aged 2–24 h repelled N. cucumeris. CONCLUSION: Predatory mites can be safely released 6 days after spinosad is applied for the management of F. occidentalis. Copyright © 2011 Society of Chemical Industry     

Chlorfenapyr resistance in the spider mite Tetranychus urticae: stability, cross-resistance and monitoring of resistance

The two-spotted spider mite, Tetranychus urticae Koch, is a key pest of many agricultural crops. Studies of stability of resistance, cross-resistance relationships and monitoring of chlorfenapyr resistance were carried out with T. urticae to provide basic information necessary to define effective acaricide resistance management strategies for this pest. Chlorfenapyr resistance was shown to be stable in the absence of selection pressure under laboratory conditions. The activities of seven different acaricides against chlorfenapyr-resistant and -susceptible strains of T. urticae were evaluated. The results indicated possible positive cross-resistance between chlorfenapyr and the acaricides abamectin, propargite and etoxazole. No cross-resistance was detected for the acaricides milbemectin, fenpyroximate and diafenthiuron. A possible negatively correlated cross-resistance was observed between chlorfenapyr and spiromesifen. The evaluation of 21 T. urticae populations from several crops in the States of São Paulo, Mato Grosso, Goiás, and Bahia, in Brazil, indicated that the susceptibility of mites to chlorfenapyr was variable, with percentages of resistant mites ranging from 0.0 to 86.5%. The highest resistance frequencies were observed in ornamental plants in the State of São Paulo. Some populations from cotton and papaya also presented high frequencies of chlorfenapyr resistance. This is the first report on chlorfenapyr resistance in T. urticae on cotton and papaya in Brazil. Strategies for the management of acaricide resistance are discussed.     

Effects of pesticides on mite predators (Acari: Phytoseiidae) and colonization of apple trees byTetranychus urticae

A 2-year survey of mite populations and pesticide use was carried out in Nova Scotia, Canada, in apple orchards where the two-spotted spider mite (Tetranychus urticae Koch) was the dominant phytophagous mite. Fungicides were the only class of pesticides that affected cumulative number ofT. urticae-days per leaf in tree canopies and colonization success — the ratio ofT. urticae-days to number of immigratingT. urticae caught in sticky bands on tree trunks. In 2000, increased numbers ofT. urticae-days in the tree canopy were associated with more frequent applications of ethylene bis-dithiocarbamate (EBDC) fungicides and with higher fungicide toxicity scores, which indicate cumulative level of suppression of the phytoseiid predatorTyphlodromus pyri Scheuten by all fungicide applications. Higher rates of colonization success were also associated with higher toxicity scores. EBDC’s applied in 2000 promotedT. urticae immigration as indicated by their counts on sticky bands. In 2000 and 2001, number ofT. pyri-days in the tree canopies was decreased by more frequent EBDC applications and by higher fungicide toxicity scores. Promotion ofT. urticae in tree canopies by EBDC’s was attributed to their toxicity toT. pyri. BothT. pyri and another phytoseiid,Amblyseius fallacis (Garman), were found in ground cover vegetation. Hence, increased immigration from the ground cover attributed to the toxicity of EBDC’s toT. pyri and, especially, toA. fallacis, which is a specialist predator of spider mites and an effective natural enemy ofT. urticae. http//www.phytoparasitica.org posting Sept. 13, 2006. Formerly, Atlantic Food and Horticulture Research Centre, now retired.     

Effects of far-red light on tritrophic interactions between the two-spotted spider mite (Tetranychus urticae) and the predatory mite Phytoseiulus persimilis on tomato

BACKGROUND

The use of light-emitting diode (LED) lights in horticulture allows growers to adjust the light spectrum to optimize crop production and quality. However, changes in light quality can also influence plant–arthropod interactions, with possible consequences for pest management. The addition of far-red light has been shown to interfere with plant immunity, thereby increasing plant susceptibility to biotic stress and increasing pest performance. Far-red light also influences plant emission of volatile organic compounds (VOCs) and might thus influence tritrophic interactions with biological control agents. We investigated how far-red light influences the VOC-mediated attraction of the predatory mite Phytoseiulus persimilis to tomato plants infested with Tetranychus urticae, and its ability to control T. urticae populations.

RESULTS

Far-red light significantly influences herbivore-induced VOC emissions of tomato plants, characterized by a change in relative abundance of terpenoids, but this did not influence the attraction of P. persimilis to herbivore-induced plants. Supplemental far-red light led to an increased population growth of T. urticae and increased numbers of P. persimilis. This resulted in a stronger suppression of T. urticae populations under supplemental far-red light, to similar T. urticae numbers as in control conditions without supplemental far-red light.

CONCLUSION

We conclude that supplemental far-red light can change herbivore-induced VOC emissions but does not interfere with the attraction of the predator P. persimilis. Moreover, far-red light stimulates biological control of spider mites in glasshouse tomatoes due to increased population build-up of the biocontrol agent. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

三种杀螨剂对山楂叶螨的毒力评价

为筛选出高效防治山楂叶螨Amphitetranychus viennensis Zacher的杀螨剂,利用玻片浸渍法和叶片残毒法测定了3种杀螨剂对其3种螨态的室内毒力,并对不同浓度杀螨剂的田间防效进行了测定。结果表明:240 g/L螺螨酯、110 g/L乙螨唑和43%联苯肼酯中仅联苯肼酯对山楂叶螨雌成螨有毒力,其LC50为37.65 mg/L;3种杀螨剂均能毒杀卵及幼螨,毒力大小依次为乙螨唑联苯肼酯螺螨酯;同一杀螨剂对幼螨的毒力均高于对卵的毒力。240 g/L螺螨酯和110 g/L乙螨唑对山楂叶螨的总体防效较好,除螺螨酯4 000倍液处理的防效在药后30 d达到最大97.11%外,其余各处理均在药后15 d达到最大,防效为88.76%~96.14%;但二者速效性较差,药后1~7 d防效均低于对照;而螺螨酯4 000、5 000倍液处理及乙螨唑5 000倍液处理的持效性较好,药后30 d防效仍有97.11%、90.90%和93.06%,均显著高于对照。43%联苯肼酯对山楂叶螨的总体防效在3种杀螨剂中最高,其1 800、2 500倍液处理分别在药后7 d和3 d时防效达到最大99.79%和98.64%;1~7 d防效为97.45%~99.79%,显著高于其余杀螨剂和对照;30 d时防效分别达98.14%和96.19%,速效性和持效性均较好。表明螺螨酯和乙螨唑对山楂叶螨的持效性较好,联苯肼酯则有良好的速效性和持效性,可以按照其不同特点推广应用。     

大环内酯类新化合物天维菌素杀螨活性及田间防治效果

为明确新化合物天维菌素的杀螨活性,采用叶碟喷雾法测定了在室内天维菌素对朱砂叶螨Tetranychus cinnabarinus、柑橘红蜘蛛Panonychus citri及二斑叶螨Tetranychus urticae的毒力,并研究了其制剂对螨类害虫的田间防治效果。结果表明,天维菌素对朱砂叶螨若螨和雌成螨均具有较高的毒力,其LC50分别为0.011、0.11 mg(a.i.)/L,杀螨活性优于弥拜霉素、阿维菌素,但杀卵活性较差。田间试验中2%天维菌素微乳剂具有良好的速效性且具有一定的持效期,在有效成分8~40 mg/kg剂量下,对朱砂叶螨和二斑叶螨药剂处理14 d的防治效果分别为83.22%~92.77%和85.49%~92.64%,有效控制期在14 d以上;在有效成分75 mg/kg剂量下,对柑橘红蜘蛛防治效果最好,处理1、3、7、14 d的防治效果分别达96.53%、97.72%、98.05%和91.42%。表明天维菌素具有作为杀螨剂的潜力。     

Note: Transovarial activity of the chitin synthesis inhibitor novaluron on egg hatch and subsequent development of larvae ofTribolium castaneum

The effects of the chitin synthesis inhibitor (CSI) novaluron on egg hatch and on larval development ofTribolium castaneum (Herbst) concentrations of 1.0, 0.3, 0.2 or 0.1 ppm were tested. The effect of novaluron at low concentrations depended strongly on the exposure period. At 0.3 ppm, egg hatch ofT. castaneum was totally inhibited after 28 days; at 0.2 ppm the effect was much less but inhibition increased progressively to 66% in the 35-day experiment; at 0.1 ppm novaluron was ineffective. The viability of the larvae that hatched from the laid eggs and developed on untreated flour was also dependent on concentration of novaluron and exposure time: exposure ofT. castaneum adults to novaluron-treated flour at 0.3 ppm for 8 days, or at 0.2 ppm for 36 days, caused 100% or 97.5% mortality, respectively. At both 0.3 and 0.2 ppm, larval deaths were mainly in the first instar. Exposure ofT. castaneum adults to treated flour may serve as a good model for evaluating the effect of CSIs on internal feeders, especiallySitophilus oryzae (L.). The present study contributes to our understanding of CSI transovarial activity against internal stored product coleopterans whose larval stage develops inside the grain without contact with the toxicants. http://www.phytoparasitica.org posting Dec. 11, 2007.     

Effects of two different neem products on different stages of Nezara viridula (L.) (Heteroptera, Pentatomidae)

In this study, the effects of two different commercial neem insecticides (NeemAzal T/S and Neem Oil) were determined on different stages of Nezara viridula (L.) (Heteroptera: Pentatomidae) under laboratory conditions. Neem Azal and Neem Oil were applied at concentrations of 0.5 % and 2 %, respectively. Mortality was recorded after 3, 7 and 14 days for nymphs and adults; 7 and 14 days for old (4-day-old) eggs; and 14 days for newly laid (one-day-old) eggs. Both products have no significant effect on adults and newly laid eggs. However Neem Oil was found to be more effective than NeemAzal T/S on nymphs and on old laid eggs after 7 and 14 days. It can be concluded that both neem products have potential for insecticidal efficacy (approximately 60 %) against nymphs of N. viridula. at concentrations recommended by manufacturers for registered pests.