苹果蠹蛾性信息素对梨小食心虫的诱集和迷向作用

【背景】在中国,苹果蠹蛾和梨小食心虫经常混合发生,但有关苹果蠹蛾迷向设置对梨小食心虫影响的研究却较少。【方法】在苹果蠹蛾和梨小食心虫同时发生的果园中设置2种迷向发散器,使用三角胶粘式信息素诱捕器监测2种昆虫的发生动态,以观察苹果蠹蛾性信息素是否会对梨小食心虫产生诱捕效果或类似的迷向作用。【结果】无论是否设置性信息素迷向发散器,苹果蠹蛾性信息素诱捕器均能诱集到梨小食心虫的雄性成虫。在2009~2011年的田间试验中,苹果蠹蛾性信息素诱捕器对梨小食心虫雄性成虫的诱集量最多能达梨小食心虫性信息素诱捕器的1.1倍,占2种诱捕器诱集总量的51.7%。在设置性信息素迷向发散器的果园中,梨小食心虫雄性成虫的诱集量受苹果蠹蛾性信息素迷向发散器的影响而下降:相比无迷向设置的对照果园,同时设置2种昆虫迷向发散器的果园中,苹果蠹蛾性信息素诱捕器内的梨小食心虫雄性成虫诱集总量最高下降了90.9%,梨小食心虫自身性信息素诱捕器内的梨小食心虫雄性成虫诱集总量最高下降了92.4%;在仅设置苹果蠹蛾性信息素迷向发散器的果园中,苹果蠹蛾性信息素诱捕器内的梨小食心虫雄性成虫诱集总量最高下降了87.5%,梨小食心虫性信息素诱捕器内的梨小食心虫雄性成虫诱集总量最高下降了60.6%。【结论与意义】苹果蠹蛾迷向发散器对于梨小食心虫雄性成虫存在"迷向"作用。在2种害虫同时发生的情况下使用2种迷向发散器,对于2种害虫能够达到比较好的防治效果。     

苹果蠹蛾性信息素诱捕器田间诱捕效应影响因子

苹果蠹蛾是我国重要的果树害虫和检疫对象.本文比较研究了性信息素诱捕器颜色、类型、放置位置、诱芯颜色及诱芯数量等对苹果蠹蛾雄性成虫诱捕效果的影响.结果表明：白色和绿色诱捕器的诱捕量是蓝色的2倍以上,诱捕效果显著优于后者;三角形诱捕器与水瓶式诱捕器的诱捕效果间不存在显著差异;放置在树冠中部的诱捕器诱蛾量是树冠上部的2倍左右,诱捕效果显著优于后者;诱芯颜色及诱芯数量对诱蛾量无显著影响.本研究结果可为苹果蠹蛾的性信息素监测技术提供指导.     

球孢白僵菌两种施用方式对侵染桔小实蝇的影响及田间的防治效果

室内研究了球孢白僵菌Beauveria bassiana不同施用方式对侵染桔小实蝇Bactrocera dorsalis的影响,以及田间喷施球孢白僵菌防治桔小实蝇的效果。结果表明,两种诱集感染方式桔小实蝇成虫存活率分别为40%、41.7%,差异不显著;添加性引诱剂在白僵菌侵染桔小实蝇的过程中没有起到明显地促进感病的作用,只是缩短了病程,IIPC为0.41-0.44,说明两种诱集感染方式对桔实蝇成虫有一定的控制作用。三种施菌方式的桔小实蝇羽化率、成虫死亡率与对照差异均显著;以IIPC为评价指标,施菌方式对桔小实蝇各因子的影响大小顺序为：成虫存活率 >羽化率>化蛹率,其中以对成虫存活率的影响最大。应用化学防治和球孢白僵菌田间防治桔小实蝇的效果表明,施用2500倍40%毒死蜱效果最好,控制作用达到71.9%,其次是喷施2.0×108孢子/mL球孢白僵菌孢子悬浮液,防效达46.9%,施用2500倍4.5%高效氯氰菊酯防治效果达最差, 防效仅37.5%。     

苹果蠹蛾诱芯性信息素含量变化及其有效时间

载有反口橡皮塞诱芯的三角式诱捕器是我国目前进行苹果蠹蛾Cydia pomonella（L.）监测的主要工具。在室内理论条件下悬挂自制的橡皮塞信息素诱芯,苹果蠹蛾性信息素释放持续时间为20周,最后1周的信息素剩余含量仍在500μg左右。在室外自然条件下,2个处理能够检测到信息素剩余含量的最后时间分别为第9周和第5周,剩余含量分别为33.3μg和37.7μg;装有该信息素诱芯的诱捕器能够诱集到苹果蠹蛾成虫的时间可达15周。综合室内和室外结果,得到该自制苹果蠹蛾诱芯的最长有效时间为15周,高效时间为4周。     

斜纹夜蛾性信息素诱捕器田间应用技术

考查斜纹夜蛾Spodoptera litura(Fabricius)性信息素诱捕器放置高度、间隔距离以及气象因子对性信息素诱集效果的影响。结果表明,放置高度为1m时,性信息素诱捕器易引起斜纹夜蛾的反应,明显优于0.5m和1.5m的诱集效果。诱捕器放置的间隔距离,以25m为诱集效果最佳,与10,15,20及30m的具有显著差异。夜间风向对诱捕器的诱蛾效果具有明显影响,在3个成一列放置的诱捕器中,诱集量最大的是放在上风口位置的诱捕器;同时,与夜间风向平行设置的诱捕器,其诱集量显著高于与夜间风向垂直设置诱捕器的诱集量。     

库尔勒香梨上苹果蠹蛾发生规律及其性信息素迷向防控效果

【目的】苹果蠹蛾是我国进境检疫性有害生物。库尔勒香梨是苹果蠹蛾在新疆果树种植区的主要寄主。研究苹果蠹蛾性信息素迷向防控技术在新疆库尔勒香梨产区的应用效果,可为该害虫的绿色防控提供参考。【方法】通过持续监测与调查,掌握苹果蠹蛾在库尔勒香梨上的发生规律和危害特点,并通过定期调查诱蛾量和蛀果率,比较微胶囊迷向剂、迷向丝、常规化学农药对苹果蠹蛾的防治效果。【结果】库尔勒香梨产区苹果蠹蛾一年发生2~3代,以老熟幼虫越冬,且死亡率较低。4月中旬越冬代羽化出土,5月开始为害;第1代成虫高峰期为7月上中旬,第2代成虫高峰期为8月下旬至9月中旬。微胶囊迷向剂、迷向丝、常规化学农药处理区每周的平均诱蛾量分别为2.85、2.98、4.95头·台~(-1),平均蛀果率分别为2.25%、0.8%、0.99%,与空白对照区的差异均达极显著水平。【结论】使用性信息迷向剂能够降低苹果蠹蛾第1代、第2代幼虫及成虫的数量。     

苹果蠹蛾迷向防治技术效果初报

2009至2011年,分别在新疆、甘肃和宁夏的3个实验点进行了苹果蠹蛾Cydia pomonella(L.)国产迷向剂的释放效果研究。结果发现,在进行了迷向处理之后,果园中雄虫平均净诱捕量下降28.6%至100%,平均下降程度为74.1%;迷向处理区中成虫平均诱捕量明显减少,对照区域则存在诱集高峰。蛀果率及树干结茧量的调查发现,2010年和2011年,与对照区相比较,迷向处理区域的蛀果率下降程度分别为32.7%和91.0%;2009年,迷向处理区的树干结茧(蛹)数量比对照区平均降低60.5%。本研究初步证实了国产迷向制剂对苹果蠹蛾具有防治效果。     

不同类型性诱剂诱芯及诱捕器组合对草地贪夜蛾诱集效果评价

本研究通过评价诱芯、诱捕器和诱芯组合的诱集效果,筛选出对草地贪夜蛾雄蛾诱捕效果最佳的诱芯和诱捕器组合,为草地贪夜蛾综合防控提供技术支持。诱芯优化筛选试验中,9种诱芯中编号为3-4、4-2、4-3的3种诱芯对草地贪夜蛾雄蛾诱捕效果最好,专一性强。诱捕器筛选试验中,5种市面上常见诱捕器里,桶型诱捕器是其他型诱捕器的诱捕效果2倍以上,效果最佳。诱芯筛选试验中,在使用桶型诱捕器及小夜蛾诱捕器的条件下,翔林3-3诱芯对草地贪夜蛾雄蛾的诱虫效果都为最佳。此研究为我国草地贪夜蛾的综合防治提供新途径。     

苹果蠹蛾幼虫爬行特性

本文通过收集苹果和梨树上的蛀果模拟自然落果,研究了苹果蠹蛾Cydia pomonella(L.)脱果幼虫的爬行特性。结果发现,58.91%的幼虫钻出蛀果进行了爬行,而41.09%滞留于果堆内部;在进行爬行的幼虫中,50%的幼虫爬行距离在0～1m之间,95%的幼虫爬行距离在0～7m之间,这意味着在实际防治过程中,落果周围0到7m的范围都需要做防治处理,而0～1m的范围需要重点防治;幼虫在果堆放置后的0～25d持续脱果,表明当果园内有落果时需要马上及时清理;幼虫结茧的高度大部分在50cm以下,在实际防治过程中,树干缚带诱杀幼虫时应将诱集带设置在距地面0～0.5m的主干上,以保证落果幼虫也可以被诱集带捕获。     

两种性信息素诱捕器对棉铃虫雄蛾的诱捕效果比较

1995年在山东和安徽棉区4个地点比较研究了性信息素笼罩诱捕器和水盆诱捕器对棉铃虫雄蛾的诱捕效果。试验结果表明,4地点笼罩诱蛾量分别是水盆诱蛾量的2.8、3.5、2.5和2.0倍,平均2.7倍。两种诱捕器诱蛾量倍数的变异系数分别为22.9%、31.5%、50.7%和51.2%。可见笼罩诱捕器比水盆诱捕器对棉铃虫雄虫具有更高的诱捕效率。考虑到笼罩诱捕器高效、稳定及简便,建议在我国尽快用其取代水盆进行棉铃虫成虫的标准化监测。     

Life stage toxicity and residual activity of insecticides to codling moth and oriental fruit moth (Lepidoptera: Tortricidae)

The codling moth, Cydia pomonella (L.), and oriental fruit moth, Grapholita molesta (Busck), are two key pests of apple (Malus domestica Borkh.) in North Carolina. Growers extensively relied on organophosphate insecticides, primarily azinphosmethyl, for > 40 yr to manage these pests. Because of organophosphate resistance development and regulatory actions, growers are transitioning to management programs that use new, reduced-risk, and OP-replacement insecticides. This study evaluated the toxicity of a diversity of replacement insecticides to eggs, larvae, and adults, as well as an assessment of their residual activity, to codling moth and oriental fruit moth. Laboratory-susceptible strains of both species were used for all bioassays. Fresh field-harvested apples were used as a media for assessing the ovicidal activity of insecticides. For larval studies, insecticides were topically applied to the surface of lima bean-based diet, onto which neonates were placed. Toxicity was based on two measures of mortality; 5-d mortality and development to adult stage. Ovicidal bioassays showed that oriental fruit moth eggs were generally more tolerant than codling moth eggs to insecticides, with novaluron, acetamiprid, and azinphoshmethyl having the highest levels of toxicity to eggs of both species. In contrast, codling moth larvae generally were more tolerant than oriental fruit moth to most insecticides. Methoxyfenozide and pyriproxyfen were the only insecticides with lower LC50 values against codling moth than oriental fruit moth neonates. Moreover, a number of insecticides, particularly the IGRs methoxyfenozide and novaluron, the anthranilic diamide chlorantriliprole, and the spinosyn spinetoram, provided equal or longer residual activity against codling moth compared with azinphosmethyl in field studies. Results are discussed in relation to their use in devising field use patterns of insecticides and for insecticide resistance monitoring programs.     

Mortality factors affecting immature stages of codling moth,Cydia pomonella (Lepidoptera: Tortricidae), and the impact of parasitoid complex

Codling moth, Cydia pomonella Linnaeus (Lepidoptera: Tortricidae), is a serious pest of apples worldwide. This study aimed to evaluate the mortality rate of codling moth eggs, larvae and pupae in the field in commercial and neglected apple and walnut orchards over two years, and to investigate the biodiversity and intensity of parasitoids associated with codling moth in the orchards. Five patches of wax paper containing 1-day-old codling moth eggs were placed in a neglected orchard in order to evaluate parasitism rates. Corrugated cardboard bands were placed around the trunk of 15 trees during late spring and the beginning of summer through to fruiting season to capture and measure parasitism of codling moth larvae. 5285 larvae in total were collected during this study. Mortality rate (egg?+?larvae?+?pupae) varied between the commercial and neglected orchards, reaching a maximum of (42.89% and 66.67%) in neglected apple orchards and (61.03% and 74.76%) in the neglected walnut orchard in 2003 and 2004, respectively. Trichogramma cacoeciae (Hymenoptera: Tichogrammatidae) was the only egg parasitoid recorded. Eight hymenopteran larval and pupal parasitoids belonging to several subfamilies were recorded: Cheloninae, Agathidinae, Cremastinae, Haltichellinae, Chalcidinae, Anomalinae, and Pteromalinae and one dipteran belonging to Tachininae. In conclusion, mortality factors, mainly by parasitoids, are contributing to a general reduction in codling moth larvae populations particularly in neglected orchards. The hymenopteran Ascogaster quadridentata and the dipteran Neoplectops pomonellae can contribute to biological control programmes against codling moth in the coastal region and other regions.     

Control of Codling Moth,Cydia pomonella (Lepidoptera: Tortricidae), with Steinernema carpocapsae: Effects of Supplemental Wetting and Pupation Site on Infection Rate

Infection of cocooned codling moth (cydia pomonella) larvae by the entomopathogenic nematode Steinernema carpocapsae was studied in three field experiments. Factors that varied within or between experiments included method of application, type of substrate containing cocooned larvae, time when nematodes were applied, seasonal effects, and supplemental wetting before or after nematode application. Conventional air-blast sprayer applications of 0.5–5.0 million infective juveniles (IJs)/tree in fall resulted in ca. 30% mortality of larvae in cardboard trap bands, whereas hand-gun application (2 million IJs/tree) produced mortality of ca. 70%. Application in the evening caused higher larval mortality than application in the morning when no supplemental wetting was used after treatments. Morning and evening applications caused equivalent larval mortality when a postwetting treatment was included. In a trial conducted in midsummer, supplemental wetting, either before or after hand-gun application of 1 million IJs/tree, enhanced nematode-produced mortality. Mortality approached 100% if both pre- and postwetting was used. Larvae in exposed cocoons on apple wood were infected at a higher rate (86%) than those on wood in less exposed positions (73%) or in nonperforated cardboard (72%). Mortality rates for larvae in perforated cardboard were intermediate (77%). Application volumes used to deliver nematodes slightly enhanced infection rate of larvae in some substrates but not others. In one trial, parasitism of codling moth by the wasp Mastrus ridibundus (Ichneumonidae) was negatively correlated with nematode infection of codling moth larvae. Dissections showed that ca. 10% of larvae infected by nematodes had been attacked by the wasp.     

Starvation induced stress and the susceptibility of the Colorado potato beetle,Leptinotarsa decemlineata,to infection by Beauveria bassiana

Starvation of second instar Colorado potato beetle larvae for 24h immediately after treatment with Beauveria bassiana conidia increased susceptibility to the pathogen and subsequent sporulation of cadavers but decreased time to larval death. In feeding studies, B. bassiana-treatment had no effect on subsequent larval development, and mortality occurred 5-6 days after treatment. Twenty-four hours of starvation alone retarded subsequent larval development but did not affect mortality. Mortality of B. bassiana-treated starvation stressed larvae occurred 4-5 days after treatment. Both B. bassiana treatment and 24h starvation significantly reduced total foliage consumption and daily weight gains. On the day of treatment, B. bassiana had no effect on the efficiency with which food was converted to biomass (ECI). ECI was not affected by B. bassiana or starvation alone on the day following treatment but was significantly affected by a combination of both. When larvae were exposed to a range of limited food quantities, ECI decreased with decreasing food availability but only extreme stress (starvation for 24h) increased susceptibility to B. bassiana. Topical application of Dacryodes excelsa resin (an antifeedant) to potato leaves caused a concentration dependent reduction in foliage consumption and weight gain by second instar larvae but did not affect larval mortality. When larvae were exposed to a fixed concentration of B. bassiana and a range of antifeedant concentrations there were significant linear relationships between 24h larval weight gain and mortality and 24h larval weight gain and sporulation. The interaction between starvation stress and the susceptibility to B. bassiana infection is discussed and its possible implications in pest management considered.     

Effect of entomopathogenic fungus, Beauveria bassiana on larvae of three species of mosquitoes

Beauveria bassiana, an entomopathogenic fungus, was evaluated for its potential against second and third instar larvae of Culex quinquefasciatus, Anopheles stephensi and Aedes aegypti. Conidiospores of this fungus were effective in causing infection leading to mortality of different larval instars. Larvae of Cx. quinquefasciatus were more susceptible to infection than An. stephensi and the second instar larvae of these two species were more susceptible than third instar larvae. Larvae of Ae. aegypti were resistant to infection by B. bassiana.     

Field evaluation of commercial formulations of the codling moth granulovirus: persistence of activity and success of seasonal applications against natural infestations of codling moth in Pacific Northwest apple orchards

Inundative applications of the codling moth (CM), Cydia pomonella L., granulovirus (CpGV), which target neonate larvae before or during initial entry into fruit, offer potential for selective control of this key pest. In field tests on apple we compared the persistence and efficacy of single applications of three CpGV products approved for organic orchards in North America. In addition, the success of repeated (2–14) applications of one product (Cyd-X) as a principal control measure for CM in apple orchards was monitored following operational use by cooperating growers at four separate locations. In the first study, an early season application of all products at label rates remained highly effective for the first 24 h (averaging 94% larval mortality relative to controls) and moderately effective after 72 h (averaging 71% mortality) during dry sunny conditions. Significant activity remained up to 14 days, suggesting prolonged survival of the virus in UV-protected locations, such as the calyx of fruit. A second application later in the season was slightly less effective. Data obtained from commercial sites provide circumstantial evidence for the effectiveness of well-timed CpGV applications against CM outbreaks. In all cases where first generation larvae were targeted beginning at egg hatch (≈250 degree days) and treated areas monitored (0.3–1.6 ha plots), fruit damage during the second larval generation was reduced or eliminated. Based on the number of live larvae recovered throughout the season, mortality rates remained high (80.3–100% across sites). The cumulative number of moths caught in pheromone-baited traps was reduced (66–94%) in the second flight. Data from tree bands placed to catch diapause-destined larvae indicated overwintering generations remained low in treated sites (0.18 larvae/band).     

A new bioassay method reveals pathogenicity of Metarhizium anisopliae and Beauveria bassiana against early stages of Capnodis tenebrionis (Coleoptera; Buprestidae)

We used a newly developed bioassay method to demonstrate for the first time the potential of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae to be used for the control of neonate larvae of Capnodis tenebrionis, a major threat to stone-fruit orchards in several countries. Four B. bassiana and four M. anisopliae isolates were all pathogenic for neonate larvae of C. tenebrionis; mortality rates 10 days after inoculation by dipping in a suspension with 10(8)conidia/ml varied from 23.5% to 100%. Three of the four M. anisopliae isolates caused 100% mortality. In most cases, postmortem hyphal growth and sporulation of M. anisopliae or B. bassiana was observed covering the larvae in their galleries. The eight isolates were also evaluated for pathogenicity to C. tenebrionis eggs at the same dosage. Only two B. bassiana isolates caused significant egg hatching reduction of 84.5% and 94.5%. Our results indicate that M. anisopliae and B. bassiana may be considered as promising for a new approach to prevent larval infestations by C. tenebrionis.     

Synergistic effect of entomogenous fungi on some insecticides against Bihar hairy caterpillar Spilarctia obliqua (Lepidoptera: Arctiidae)

A number of fungal parasites infect a wide range of insects and cause epizootics from time to time. Beauveria bassiana (Balsamo) Vuillemin and Metarhizium anisopliae (Metschnikoff) Sorokin are two of the major disease-causing fungi in insects. Investigations were carried out to study the effect of these fungi on the toxicity of endosulfan, imidacloprid, lufenuron, diflubenzuron, dimethoate and oxydemeton methyl against 10-11 days old larvae of Spilarctia obliqua (Walker). For some products the combination treatments showed higher dose mortality response than the sole treatment of fungal conidia or the insecticide. The combination of insecticides with B. bassiana showed 1.26-35.8 fold increase in toxicity of insecticides over sole treatment, while the increase was 1.05-72.0 fold in case of M. anisopliae. Imidacloprid 17.8 SL and oxydemeton methyl 25EC may be used in combination with these fungi for management of S. obliqua.     

苹果蠹蛾的蛀果与脱果特性

苹果蠹蛾Cydia pomonella(L.)是我国重大植物检疫性有害生物,对苹果属以及梨属的水果生产造成严重的危害。该虫以初孵化的1龄幼虫蛀入果肉,在果实内部取食为害并完成发育,老熟幼虫在黑暗中离开果实并寻找场所结茧化蛹。为掌握苹果蠹蛾幼虫进入及脱出果实时的行为特性,从而为实施有效的防治措施提供基础信息,本文在内蒙古格棱布楞滩对苹果蠹蛾幼虫的蛀果与脱果特性开展了详细研究。取得的主要研究结果如下:1)在苹果蠹蛾种群密度较高的情况下,单个果实平均蛀孔数可达5.25个,初期蛀入果实的幼虫在2～8头之间;2)苹果及梨蛀果中的幼虫数量与蛀孔数无关,虽然果实上的最高蛀孔数可达14个,但一般情况下受害果实中的幼虫数不超过3个;3)当果实表面蛀孔数较多时(苹果超过5个,梨超过2个),苹果蠹蛾幼虫向种室钻蛀的行为发生偏移,通常转入在果肉中为害;4)落果后5d内,落果内的幼虫近半数脱果(43.1%),落果后15d内,落果内的幼虫几乎全部脱果(99.9%);5)在脱果幼虫中,94%选择在夜间脱果,6%在日间脱果;6)至试验结束,蛀果中还有64%的幼虫滞留。以上研究结果表明,在种群密度较高的情况下,苹果蠹蛾幼虫存在激烈的种内竞争;及时清除苹果蠹蛾幼虫蛀果后造成的落果对未脱果幼虫有很好的防治效果。     

Diatomaceous earth increases the efficacy of Beauveria bassiana against Tribolium castaneum larvae and increases conidia attachment

This research tested the suppressive ability of Beauveria bassiana (Balsamo) Vuillemin alone and in combination with diatomaceous earth against the red flour beetle, Tribolium castaneum (Herbst). Adults did not show a dose response to B. bassiana, and the addition of diatomaceous earth (DE) did not result in a significant increase in mortality. Against larvae, however, DE at 190 mg/kg grain enhanced the efficacy of B. bassiana at all concentrations ranging from 33 to 2,700 mg of conidia per kilogram of grain. The presence of DE resulted in 17- and 16-fold decreases in the median lethal concentration of B. bassiana at 56 and 75% RH, respectively. No significant differences in larval mortality in response to B. bassiana and diatomaceous earth alone or in combination were found between 56 and 75% RH. Conidial attachment to larvae was significantly greater with 190 mg/kg DE than without it. The partial analysis of lipids taken up by DE from the larvae revealed the removal of phospholipids and long-chain fatty acids. These results support the hypothesis that diatomaceous earth enhances the efficacy of B. bassiana against larval T. castaneum, at least in part by damaging the insect cuticle, thus increasing conidial attachment and making nutrients more available to conidia for their germination.