Insecticidal effect of the combined application of spinosad,Beauveria bassiana and diatomaceous earth for the control of Tribolium confusum

Laboratory bioassays were carried out to evaluate the insecticidal effect of Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) germinated conidia, a commercial formulation of diatomaceous earth and a liquid formulation of spinosad, applied alone or in all possible combinations on wheat, against adults of the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae). Diatomaceous earth was applied at one (200 ppm), the fungus at two (100 and 300 ppm) and spinosad at three (0.01, 0.1 and 0.5 ppm) dose rates, whereas all combinations of two or three of the insecticide concentrations were also tested. Insect mortality was determined after 2, 7 and 14 d of exposure. The simultaneous use of B. bassiana germinated conidia with diatomaceous earth notably increased mortality of T. confusum adults by sixfold 7 d after exposure, as compared with either B. bassiana or diatomaceous earth alone. When diatomaceous earth and spinosad were combined, diatomaceous earth did not increase the efficacy of spinosad. In general, the combination of all three agents did not differ from either the application of the agents tested alone, or their binary combinations, in most treatments examined.     

Mixing of Isaria fumosorosea with enhanced diatomaceous earth and bitterbarkomycin for control of Rhyzopertha dominica

The virulence of Isaria fumosorosea alone and integrated with an enhanced formulation of diatomaceous earth (diatomaceous earth + bitterbarkomycin, DEBBM) was tested against the lesser grain borer Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) under laboratory conditions on stored wheat. The fungus was applied to wheat grains at various concentrations of 3.60 × 10⁶, 3.60 × 10⁸, and 3.60 × 10¹⁰ conidia/kg alone, or in combination with 15 and 30 ppm of DEBBM. R. dominica was held at 20, 25 and 30°C and two RH regimes (56 and 75%) and mortality was registered after 5, 10 and 15 d. Generally, I. fumosorosea was most effective at 25°C caused the highest mortality of R. dominica at 56% RH. The increase of temperature, concentration and exposure interval increased the insecticidal effect of DEBBM at low RH level. The DE alone suppressed the progeny emergence at higher dose rate as compared I. fumosorosea alone, but their simultaneous use further reduced the progeny production of R. dominica. The integrated use of both tested bio control agents synergized the effect of each other and caused the highest mortality at 25°C and 56% RH. The results clearly demonstrated that I. fumosorosea and new enhanced DEBBM can be integrated to be an effective control measure for R. dominica in stored wheat.     

Beauveria bassiana infection of eggs of stored-product beetles

Beauveria bassiana (Balsamo) Vuillemin was tested under maximum challenge conditions with an estimated dose of 1.1 × 10⁵ conidia/mm² for its effects on eggs of four of the major beetle pests of stored grain and grain products. When ambient relative humidity (RH) was 92%, hatch of fungus-treated Rhyzopertha dominica (Fabricius) eggs was 13% versus 58% for control eggs, and hatch of treated Tribolium castaneum (Herbst) was 17% versus 51% for controls. There was no fungus effect at RH of 48 and 73%. Fungus treatment of Cryptolestes ferrugineus (Stephens) and Oryzaephilus surinamensis (Linnaeus) eggs had no effect. Sectioned T. castaneum eggs demonstrated that the fungus penetrates and infects them.     

Efficacy of Beauveria bassiana for control of Tribolium castaneum with reduced oxygen and increased carbon dioxide

This study investigated the effect of atmosphere modification, a widely adopted means of insect control in stored products, on the efficacy of Beauveria bassiana for one of the most difficult to control pests, Tribolium castaneum. Oxygen reduction to 5% (±1%) as opposed to CO₂ elevation to 40% (±2%) for the first 72 h of fungus exposure resulted in significantly greater larval mortality than fungus exposure under ambient atmospheres. Both treatments reduced pupation of older larvae suggesting that slowed development may be a beneficial factor for fungal efficacy. CO₂ elevation but not O₂ reduction significantly affected the mortality of adult beetles that were exposed to the fungus. Carbon dioxide elevation significantly reduced B. bassiana’s germination and growth rates, but oxygen reduction did not.     

A study of host specificity in the entomopathogenic fungus Beauveria bassiana (Hypocreales,Clavicipitaceae)

Beauveria bassiana (Balsamo – Crivelli) Vuillemin based mycoinsecticides are used against agricultural, veterinary and medical insect pests. The fungus has a very diverse and extensive host range. Variation in virulence among isolates of B. bassiana to different insect species has been abundantly documented. Given the effect of multiple factors on virulence, it is not certain whether the observed difference in virulence can be labelled as host specificity. Environmental conditions and susceptibility of the insect population are two main factors that affect successful fungal infection. Keeping the environmental factors constant, if virulence of an isolate to different insect species and different populations within an insect species is compared, the scale of difference between the two responses can be estimated. If differences in virulence of an isolate to different insect species are greater than the difference in virulence to different insect populations within an insect species, then, the isolate can be considered as exhibiting specific preference to those insect species towards which it exhibits high virulence. To examine this feature, a worldwide sample of B. bassiana was bioassayed on nine insect species and two different populations within two insect species. Laboratory bioassays were done on: Bombyx mori (Lepidoptera), Spodoptera litura (Lepidoptera), Chilo partellus (Lepidoptera), Helicoverpa armigera (Lepidoptera), Epilachna vigintioctopunctata (Coleoptera), Mylabris pustulata (Coleoptera), Aphis craccivora (Homoptera), Maconellicoccus hirsutus (Hemiptera) and Oecophylla smaragdina (Hymenoptera). The range of variation in virulence of a B. bassiana isolate to different insect species was not more than that observed with different populations within a single insect species. B. bassiana is thus a generalist with no strict host preference. B. bassiana based biopesticide can be used as a broad spectrum insecticide against a myriad of insect pests.     

Efficacy of Beauveria bassiana applications on coffee berry borer across an elevation gradient in Hawaii

ABSTRACT

The effect of three rates of a commercial formulation of Beauveria bassiana Strain GHA was evaluated against the coffee berry borer (CBB) Hypothenemus hampei Ferrari (Coleoptera: Curculionidae: Scolytinae), at three commercial coffee farms located at different altitudes on the island of Hawaii. H. hampei infestation and natural prevalence of B. bassiana increased with the elevation. At 145 metres above sea level (Farm 1), beetle infestation was 3.9%; at 538?m (Farm 2), beetle infestation was 12.2%; and at 768?m (Farm 3) infestation was 22.3%. The prevalence of natural B. bassiana killing CBB was 5.5% on Farm 1, 3.3% on Farm 2 and 23.1% on Farm 3. Monthly applications of B. bassiana resulted in no significant differences in levels of CBB infestation among treatments. Similarly, rates of infested berries with visually detectable signs of B. bassiana were similar among the B. bassiana treatments, ranging from 0.44% to 4.24%, and those percentages were larger than the treatments without B. bassiana. The percentage of females killed by Beauveria ranged from 69% to 95%. Effect of dose of BotaniGard^® ES was reduced when beetles were in C position compared to A and B positions. B. bassiana can be an important component of an integrated pest management program for CBB.     

Evaluation of Beauveria bassiana (Hyphomycetes) isolates as potential agents for control of Dendroctonus valens

Abstract The red turpentine beetle (RTB), Dendroctonus valens LeConte, as a destructive invasive pest, has become one of the most economically important forest pest in China. Effective control measures are desperately needed. Entomopathogenic fungi, such as Beauveria bassiana, have shown great potential for the management of some bark beetle species. In this study, 12 isolates of B. bassiana from bark beetle were examined for biological characteristics and virulence, to assess their potential as biocontrol agents for RTB. There were significant differences (at P= 0.05) in colony growth rate, conidial yield, conidial germination, tolerance to UV light and extracellular proteases activity among the tested B. bassiana isolates. Isolates, including Bb1801, Bb1906, Bb789 and Bb773, exhibited the best characteristics, because they have faster hyphal growth rate, higher spore production and faster spore germination, higher UV tolerance and protease (Pr1) production. The results of a pathogenicity test of B. bassiana on RTB larvae showed that most isolates of B. bassiana have demonstrated high efficacy and the highest virulent isolate was Bb1801, which killed 100% of the treated insects and had a median lethal time (LT₅₀) of 4.60 days at a concentration of 1×10⁷ conidia/mL. Therefore, isolate Bb1801 has a great potential for sustainable control of RTB in the forest. The correlation between biological characteristics and virulence of the fungal isolates is discussed and the possibility of combination of entomopathogenic fungi with semiochemicals, as one of the promising strategy for RTB control, is considered.     

Field evaluation of Beauveria bassiana efficacy for the control of Tetranychus urticae Koch (Acari: Tetranychidae)

Trials with eggplants were conducted to evaluate field efficacy of Beauveria bassiana (Bb) applications against Tetranychus urticae, during spring of 2006 and 2007. In the 2006‐Trial, a rate of ca. 0.7 × 10¹² conidia/ha was sprayed onto plants at intervals. In the 2007‐Trial, the rates of ca. 0.8 × 10¹² and 1.6 × 10¹² conidia/ha were sprayed at 1‐ or 2‐week intervals. Based on population densities of mites and leaf damage assessed throughout the trial, the Bb sprays with 1‐ or 2‐week interval showed better control than those of 3 or 4 weeks. In both trials there was no statistical difference between 1‐week and 2‐week spray interval for all parameters measured. Furthermore, the higher rate performed significantly better than the lower rate, regardless of the intervals. No interaction was found between the spraying interval and the applied rate. Ultimately, to suppress the population density of T. urticae and prevent the eggplant damage in spring, the higher rate applied at 2‐week interval was effective.     

球孢白僵菌对黄瓜代谢产物及西花蓟马取食行为的影响

球孢白僵菌Beauveria bassiana灌根处理黄瓜后,发现西花蓟马Frankliniella occidentalis对叶片危害面积显著低于对照组;为探究产生这一现象的原因,测定黄瓜叶片中防御酶系和次生代谢产物等含量变化,采用直流刺吸电位仪(direct current electrical penetration graph,DC-EPG)分析西花蓟马成虫取食黄瓜叶片的行为.球孢白僵菌对黄瓜灌根后叶片中过氧化氢酶(CAT)、过氧化物酶(POD)和超氧化物歧化酶(SOD)含量均呈上升趋势,其中CAT活性增加最高,增加率为37.26％;丙二醛MDA的含量呈下降趋势;可溶性蛋白、类黄酮的含量增加.DC-EPG显示西花蓟马在经球孢白僵菌处理的黄瓜上,取食时间和次数均低于对照组.结果表明,黄瓜植株经球孢白僵菌处理后防御酶物质增加,进而导致西花蓟马对叶片危害下降,利于对西花蓟马的防治.     

Population development of Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) on different stored products

The lesser grain borer, Rhyzopertha dominica, is an important pest of various stored products around the world. In this study, the development, survival, reproduction, and life table parameters of R. dominica were investigated on six stored products (angelica, jujube, maize, rice, soybean, and wheat). The developmental time of the immature stage of R. dominica was shortest on wheat (40.20 days) and longest on angelica (67.04 days). The survival rate of the immature stage was highest on wheat (76.33%) and lowest on angelica (41.00%). The fecundity level of R. dominica was highest on wheat (246.05 eggs/female) and lowest on angelica (69.38 eggs/female). The net reproductive rate (R₀) and intrinsic rate of increase (r_m) of R. dominica differed significantly among the six stored products. The highest R₀ of R. dominica was on wheat (68.50), followed by rice (41.28), maize (32.32), soybean (27.17), jujube (23.16), and angelica (20.18); the r_m values showed a similar trend, with values of 0.059, 0.046, 0.042, 0.039, 0.036, and 0.033, respectively. Our results indicate that wheat was the most suitable stored product, whereas angelica was the least suitable, for the feeding, development, and population increase of R. dominica. These findings provide basic information about the occurrence trends and characteristics of R. dominica that will be useful for the control of this pest on different stored products. The physicochemical properties of angelica should be further explored for potential application in the control or integrated management of R. dominica.     

Beauveria bassiana affects immature stage development of Prostephanus truncatus (Coleoptera: bostrichidae) in stored maize

Recent research in Ghana has demonstrated the effectiveness of an isolate of B. bassiana, sensu lato (IMI 389521) from the U.K. against the larger grain borer Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), a major pest of stored maize. To determine whether this isolate is effective on immature stages of P. truncatus, a laboratory study of the response of immature stages (egg, larvae and pupae) of P. truncatus in maize grains to two concentrations (1?×?10⁹ and 3.16?×?10⁹?cfu/kg maize) of B. bassiana, IMI 389521 formulated with Entostat? and kaolinite was undertaken. Adult emergence, per cent survival of adults that emerged and the number of larvae in each immature stage were assessed after 45 days. Apart from the egg experiment, higher numbers of adults emerged in grains containing larvae and pupae treated with B. bassiana product compared to the untreated maize control. This notwithstanding, survival of emerged adults of P. truncatus was greatly reduced in B. bassiana treatments (<10%) compared with 75–95% in the controls. Surface treatment with B. bassiana on pre-infested maize showed a significant effect on the developmental biology of P. truncatus in Ghana.     

白僵菌防治菜青虫的研究

通过应用6株白僵菌不同菌株对菜青虫幼虫进行室内和田间防治试验比较,结果表明,不同菌株间的毒力存在显著差异,以筛选自菜青虫僵虫尸上的Bpr3菌株毒力最强,用浓度为1×108 mL-1的孢子液对菜青虫幼虫进行室内和田间感染,室内幼虫校正死亡率达100%,LT50为2.9806 d,田间防治效果达96.6%,经大面积示范应用,取得了显著的防治效果.     

美国白蛾高毒力球孢白僵菌菌株筛选

【目的】美国白蛾Hyphantria cunea(Drury)是世界性检疫害虫,目前已经入侵到我国长江下游地区(从辽宁丹东至安徽芜湖)。作者在前期研究中,在芜湖地区成功获得了被球孢白僵菌Beauveria bassiana侵染的美国白蛾僵虫。本研究拟在前期已获取菌株的基础上,筛选生物学性状良好且对美国白蛾幼虫具有高致病力的球孢白僵菌菌株,以期为我国长江下游地区利用昆虫病原真菌防治美国白蛾奠定基础。【方法】对采集自美国白蛾僵虫的7株球孢白僵菌菌株(Bb01-1,Bb08-5,Bb08-6,Bb08-11,Bb22-2,Bb22-3和Bb22-5)进行生物学特性研究,以候选菌株菌落形态、生长速率、产孢量、萌发率和抗紫外能力等参数确定优良菌株;并将生物学性状良好的球孢白僵菌菌株配制成5个浓度(5×10~6,1×10~7,5×10~7,1×10~8和5×10~8孢子/m L)的孢悬液,采用浸渍法处理美国白蛾4龄幼虫,以幼虫死亡率、侵染率等指标评价菌株的致病力。【结果】供试菌株Bb22-2,Bb22-3和Bb22-5为粉状菌落,其菌落直径大,产孢早且孢子层厚;同时,这3个菌株在菌落生长速率和产孢量以及孢子萌发率、紫外照射处理后的萌发率也均显著优于其他4个菌株。毒力测定结果表明,这3个菌株对美国白蛾4龄幼虫表现出很强的致病力,各菌株处理11 d后美国白蛾幼虫校正死亡率为80%~90%。这3个菌株对美国白蛾幼虫的侵染率均高(侵染率53%~87%),并且呈现随浓度升高侵染率上升的趋势。其中,菌株Bb22-2侵染率均要高于其他2个菌株。【结论】本研究成功筛选获得了生物学性状良好且对美国白蛾高毒力的球孢白僵菌菌株。鉴于中国长江下游地区气候特点与美国白蛾生物学习性,可以预期采用昆虫病原真菌防治美国白蛾在该地区将具有很好的应用前景,但其实际应用价值尚需进一步的田间试验进行确认。     

对蜱致病性球孢白僵菌培养条件的优化

对前期筛选得到的具有生防潜力的杀蜱真菌Beauveria bassiana AT17菌株进行相关生物学性状的研究,建立一套规范的实验室培养的技术和方法,同时对其液固双相发酵技术进行优化,在于提供优质高效的生防材料,为其真菌制剂的规模化生产提供实践和理论基础。通过采用单因素筛选方案对其最适基础培养基、温度、pH值、碳源、氮源、微量元素及液固双相发酵配方进行研究,发现该菌株在PDA、PPDA、PDAY、SDAY、SMAY 5种培养基上均能较好生长,在PDA上生长最快,在PDAY上产孢量最大。温度对菌丝的生长和产孢影响显著,25°C菌丝生长最快,且产孢量最大。B.bassiana AT17菌株在pH 4-10范围内均可生长,在偏碱性环境内生长最快,在pH 5-6的偏酸性环境内产孢量最大。综合评价真菌各项指标后,葡萄糖和酵母粉为菌丝生长和产孢的最佳碳源和氮源,固体物料麦麸+玉米粉+米粉与基础培养液3/4 SDAY按2:1均匀混合后,添加0.05%K+可作为菌株固体发酵的最佳物料配方组合。     

应用白僵菌与溴氰菊酯混合防治马尾松毛虫研究

通过应用白僵菌粉与4种浓度溴氰菊酯粉混合后不同时间孢子萌发情况测定,以及用纯菌粉、药粉和菌药不同比例混合粉,对马尾松毛虫室内毒力测定和林间防治试验比较,筛选出菌粉与0．05％溴氰菊酯粉按4：1比例混合,防治效果最好,并经大面积推广防治示范,平均防治效果达95％以上,分别较纯菌粉和药粉效果提高14．9％和29．5％,具有明显的增效作用,马尾松毛虫死亡高峰期提前5－7天,减少松针损失量,能及时控制住高虫口林分害虫的严重危害、经济、社会和生态效益显著。     

Introduction of Beauveria bassiana as a biological control agent for Tribolium castaneum in Kerman province

Barley, Hordeum vulgare, one of the important crops in the word, is used in malting, feed and food industries. The red flour beetle, Tribolium castaneum, was found wherever grains or other dried foods are stored. Disinfestations of barley using chemical methods to kill insects, in this research, for the first time we isolated the pathogenic KB512 of entomopathogenic fungi Beauveria bassiana from soil and insects, which produced aerial and submerged conidia and blastospores in laboratory conditions. We investigated the best conditions for the production and utilisation of spore suspension to spray the larvae of T. castaneum, which is one of the important pests in Kerman province (Iran). One hundred and eighty isolates that naturally infected by T. castaneum were reared during spring and summer seasons 2010–2011. The pathogenicity test was carried out with direct spray. To bioassay the isolates, three concentrations of the spore suspension were prepared as follows: 1?×?10⁶ and 1?×?10⁸ conidia/ml. The pests were sprayed by aerial conidial suspension, which was prepared by 0.01% Tween 80 in distilled water, and the controls were sprayed by 0.01% Tween 80 in distilled water. After spraying the pests, the plates were incubated at 25?±?1?°C and 80% of relative humidity. Then, the treated pests were monitored every day for the fungal growth and mortality.     

Entomopathogenic fungus as a biological control agent against Rhyzopertha dominica F. (Coleoptera: Bostrychidae) on stored wheat

To evaluate the pathogenicity of Metarhizium anisopliae (Metschinkoff) Sorokin (Deuteromycotina: Hyphomycetes) a bioassay was designed under laboratory conditions against Rhyzopertha dominica F. (Coleoptera: Bostrychidae) on stored wheat. The fungus was applied at the dose rates of 8 × 10³, 8 × 10⁵, 8 × 10⁷ and 8 × 10⁹ conidia/kg of wheat and the bioassay was conducted at 25°C with 60% relative humidity. The data regarding the mortality was recorded after 7 and 14 days exposure intervals. All the treatments gave the significant mortality of R. dominica and M. anisopliae of 8 × 10⁹ conidia/kg was found to be the most effective after a 14-day exposure interval. There was greater production of progeny when the low rate of M. anisopliae was applied to wheat. Overall, our study showed that M. anisopliae is vigorous when applied at a high dose rate which revealed an effective control of R. dominica and also played a pivotal role in the integrated pest management program (IPM) of stored wheat insect pests.     

Horizontal transmission of Beauveria bassiana (Bals.) Vuill

1 Factors influencing horizontal transmission of the entomopathogen Beauveria bassiana in the Colorado potato beetle (CPB) were examined through a series of laboratory studies. 2 Cadaver density, cadaver life stage, ambient temperature and conidial density were the factors manipulated. 3 Mortality and sporulation of burrowing CPB prepupae both increased significantly with increased sporulating second‐instar cadaver density on the soil surface. 4 Mortality rates were significantly higher when prepupae were released into laboratory arenas containing third‐instar cadavers compared to second‐instar cadavers. 5 Mortality and sporulation decreased significantly as temperature increased from 15 °C to 30 °C, however, no temperature‐dependent behavioural response by prepupae could be identified as a potential cause. 6 An 86.1% decrease in conidial density per cadaver had no significant effect on mortality or sporulation of prepupae, indicating that this level of environmental degradation of cadavers may not significantly reduce the probability of horizontal transmission.     

Reduction of grasshopper populations following field application of the fungus Beauveria bassiana

Conidia of the Hyphomycete fungus Beauveria bassiana (Bals.) were applied in an attempt to reduce field populations of grasshoppers, primarily the migratory grasshopper Melanoplus sanguinipes (Fabricius). Dry spores were applied with wheat bran carrier to three fallow fields at a rate of 2.0 × 10¹³ spores ha^?1 in 10 kg bait ha^?1. Examination of culture plates that had been placed in the field to capture spores and of bran carrier with scanning electron microscopy indicated that a substantial portion of the B. bassiana colony—forming units (spores and clumps of spores) did not adhere to the bran and were applied in the field as free particles. Grasshoppers collected from the treated plots at intervals after application were assayed for infection by B. bassiana. The observed rate of mycosis in the treated populations was 70% of those collected after 2 days, declining to 41% by 13 days and 5% by 19 days after application. Analysis of reductions in population density gave results in agreement with the infection data. Treated populations declined 60% and 33% by 9 and 15 days after application respectively. The reductions were significant on both post—treatment sampling dates (p < 0.05) and the three replicated fields gave comparable results. This is the first field demonstration of effectiveness of this fungus as a microbial control agent of grasshoppers.     

Potential of oil-based formulations of Beauveria bassiana to control Triatoma infestans

The in vitro development of Beauveria bassiana conidia was monitored when immersed in six concentrations of seven non-ionic (MP 6400, MP 600, Renex 60, Renex 95, Span 80, Tween 20 and Tween 80) and three anionic (DOS 75, Hostapaval BVQ 9 and Surfax 220) surfactants and 11 vegetable oils (linseed, soybean, groundnut, rapeseed, thistle, sunflower, olive, sesame, corn, castor, and babassu). The influence of the oils on the settling behavior of Triatoma infestans nymphs and the activity of an oil–water formulation of the fungus against this vector under laboratory and simulated field conditions were also determined. With exception of DOS 75 and Surfax 220 germination of conidia on complete medium was >98% at 24 h after exposure to surfactants up to 10%. Elevated rates of germination (>25%) were observed in 10% corn, thistle and linseed oil 8 days after incubation. Pure oils had a significant repellent effect to T. infestans. Repellency decreased generally at 10% of the oil and some oils showed some attractiveness for nymphs when tested at 1%. Nymphs were highly susceptible to oil–water formulated conidia, even at unfavorable moisture for extra-tegumental development of the fungus on the insect cuticle.