Metarhizium anisopliae and Beauveria bassiana: Pathogenicity, Horizontal Transmission, and Their Effects on Reproductive Potential of Thaumatotibia leucotreta (Lepidoptera: Tortricidae)

2020 ◽  
Vol 113 (2) ◽  
pp. 660-668 ◽  
Author(s):  
Abdullah Mohamed Mkiga ◽  
Samira Abuelgasim Mohamed ◽  
Hannalene du Plessis ◽  
Fathiya Mbarak Khamis ◽  
Komivi Senyo Akutse ◽  
...  

Abstract The polyphagous moth, Thaumatotibia leucotreta (Meyrick) is among the major constraints to the horticultural industry in East Africa. In a search of sustainable control methods, the pathogenicity of the dry conidia of 17 Metarhizium anisopliae (Metschn.) and five Beauveria bassiana (Bals.) (Vuill.) isolates were tested against T. leucotreta moths. The conidial uptake by a single moth, horizontal transmission, and effect of fungal inoculant on egg-laying and hatchability for the pest were also assessed. The findings from this study showed that tested fungi were virulent to the moths, with 12 isolates causing mortality that ranged between 58.8 and 94.2% for M. anisopliae and three isolates between 57.6 and 84.6% for B. bassiana. The entomopathogenic fungi isolates, M. anisopliae ICIPE 69 and B. bassiana ICIPE 279 were highly virulent with low lethal times to 50% mortality (LT50) of 3.81 and 5.13 d, respectively. The isolate, ICIPE 69 conidia acquisition by a single moth were approximately 4.58 × 106 and 3.51 × 106 for males and females, respectively. The lowest survival rate (3.33 %) caused by inoculum transmission was recorded in donor males compared to 16.67% in recipient males. Fecundity was reduced by 33.6 and 25.9% for donor and recipient females, respectively. The pest can acquire conidia from the treated substrate and transmission is then possible between adults. ICIPE 69 is virulent and reduces the reproduction potential of the pest after transmission. The findings are discussed in the prospects of microbial control of this pest using an autodissemination technique.

2019 ◽  
Vol 30 (1) ◽  
pp. 1
Author(s):  
Agus Kardinan ◽  
Tri Eko Wahyono ◽  
Nurbetti Tarigan

<p>Brown plant hopper (Nilaparvata lugens Stal) is the main pest on rice cultivation.  Synthetic insecticides application had negative impact to the human health and environment. The research objective was aimed to examine the effectiveness of botanical (pyrethrum and neem) and bio-insecticides (Beauveria bassiana/Bb and Metarhizium anisopliae/Ma) against brown plant hopper. Research was conducted at Entomology Laboratory of Indonesian Spices and Medicinal Crops Research Institute, Bogor in 2017. Trial consisted of two activities: the effectiveness of botanical and bio-insecticides to brown plant hopper mortality and horizontal transmission of bio-insecticides on brown plant hoppers. Botanical pesticide tested was (1) pyrethrum I (5 ml.l-1 water ), (2) pyrethrum II (5 ml.l-1 water), (3) neem I (20 ml.l-1 water), (4) neem II (20 ml.l-1 water), (5) synthetic insecticide (2 ml.l-1 water) and (6) control.  Bio-insecticide treatments were (1) Bb (spraying, 2.5 ml/plant), (2) Bb (granule, 5 g/pot), (3) Ma (spraying, 2.5 ml/plant), (4) Ma (granule, 5 g/ pot) and (5) control.  Treatments of horizontal transmission was the ratio of infected : healthy brown plant hopper 1 : 10; 2 : 10; 3 : 10 and 4 : 10. Botanical insecticides were prospective to suppressing brown plant hopper population of 85-87 % (pyrethrum) and   60-70 % (neem).   B.  bassiana was able  to   suppress   brown   plant     hopper population (18.2%), better than   M. anisopliae (5.6 %). Biological insecticide application by contact (spraying) was better than applied in granules form.  Botanical insecticide application showed no horizontal transmission from infected to healthy insect. Botanical insecticide (pyrethrum and neem) was more prospective than bio-insecticide (B. bassiana and M. anisopliae) in controlling brown plant hopper. </p>


ENTOMON ◽  
2020 ◽  
Vol 44 (4) ◽  
pp. 249-258
Author(s):  
Umme Habiba ◽  
Wahedul Islam ◽  
Selina Parween

Spinodad of different concentrations were screened against Tribolium castaneum (Herbst) reared on four local wheat varieties to observed the effects on reproductive potentials for two successive generations.The lowest number of eggs laid was 119 (23.80±0.97) observed in Shatabdi- 21 (S-21) in 45 d in F1 and 15 (3.00±0.71) in 15 d in F2 generation when treated at 0.12ìl/g of spinosad. Spinosad at all concentration totally inhibited egg laying oroviposition rate on day 45 in all wheat varieties except P-24 variety in F1 generation.The lowest fertility was found in Shatabdi-21 variety as 12.61percent in F1 and 6.67 percent in F2 generation at 0.12ìl/g.The latent effect of spinosad on number of eggs, larva, pupa and adult obtained in Shatabdi-21 as 2.00±0.32,0.80±0.37, 0.40±0.40 and 0.20±0.20 at 0.12ìl/g of spinosad in F2 generation.There was no significant difference between the number of males and females in F2 generation wheat varieties. Spinosad ultimately reduced the fecundity, fertility and decreased the egg to adult survivability in four wheat varieties compared to control and F1 and F2 generations. Results of the research revealed that comparatively higher concentrations of spinosad that used in this study would potentially control development and reproductive potentiality of T. castaneum in wheat varieties.


Author(s):  
Atef M M Sayed ◽  
Christopher A Dunlap

Abstract Six fungal isolates of Beauveria bassiana (Balsamo) Vuillemin and one isolate of Metarhizium anisopliae (Metschnikoff) Sorokin were isolated and evaluated for their pathogenicity to Icerya seychellarum (Westwood) and Aulacaspis tubercularis Newstead. There is a positive correlation between the concentration of the fungal blastospore concentrations and the percentage of mortality. Bio-efficacy increased significantly after inoculation with increasing concentration of blastospores and elapsed time up to 12 d after inoculation. The mortality of nymphs exposed to fungal isolates at various concentrations varied between 2.5 and 88.8%. Probit analysis of data at 95% confidence limits of LC50 and LT50s showed significant differences in the susceptibility of nymphs of I. seychellarum and A. tubercularis to the tested fungal isolates. The fungal isolates of Egy-6 and Egy-9 were the most effective against I. seychellarum and A. tubercularis, respectively. They had the lowest LC50 (4.20 × 105 and 5.71 × 103 blastospore ml−1) and LT50 (ranged from 4.61 to 9.79 and 4.84 to 8.71 d), respectively. The current study showed that all the fungal isolates yielded moderate mortality rates of nymphs and adult female populations of both the tested insect pests. To our knowledge, this is the first report of bio-efficacy of Beauveria and Metarhizium isolates against members of the Diaspidadae and Monophlebidae family insects. These results establish that the use of these native entomopathogenic fungi isolates of B. bassiana (Egy-3, Egy-4, Egy-6, Egy-7, Egy-9, and Egy-10) and M. anisopliae (Egy-5) could be considered for further development as microbial control agents of the mealybug and scale insects as a potential biological agent for use in an IPM program.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kim Khuy Khun ◽  
Gavin J. Ash ◽  
Mark M. Stevens ◽  
Ruth K. Huwer ◽  
Bree A. L. Wilson

AbstractKuschelorhynchus macadamiae is a major pest of macadamias in Australia, causing yield losses of up to 15%. Our previous studies have shown the weevil is susceptible to Beauveria bassiana and Metarhizium anisopliae. The aim of this study was to investigate horizontal transmission of both fungal species to healthy weevils from both infected adults and weevil cadavers. In a confined environment the mortality of healthy adults caused by the transmission of conidia from live fungus-infected adults was < 50%. Under similar experimental conditions, the mortality of healthy adults reached 100% when exposed to conidiated cadavers. However, when conidiated cadavers were used in more spacious environments (insect cages), the mortality of adults was < 80%. Using scanning electron microscopy, it was observed that all healthy adults had conidia attached to all external parts of the body. This suggests that although the conidia were readily transferred to the adults, the lower mortality in the larger insect cages could be the result of an unfavourable environmental factor such as low humidity. The presence of conidia attached to all the adults indicated that they did not show any discriminatory behaviour such as avoidance of conidiated cadavers infected by these two fungal species. The results from this study show that there is potential for enhanced control of adult K. macadamiae via transmission from either fungus-infected adults or conidiated cadavers and this could strengthen sustainable pest management in macadamias.


2009 ◽  
Vol 5 (9) ◽  
pp. 25-38
Author(s):  
Martha Giselle Rivera Pineda ◽  
Sandra Patricia Garzón Lozano ◽  
Luz Inés Villarreal Salazar

En busca de una alternativa de control del mosquito Culex quinquefasciatus en áreas urbanas se desarrolló el proyecto: “Evaluación de microorganismos biocontroladores sobre el mosquito Culex quinquefasciatus” cuyo objetivo fue evaluar la capacidad biocontroladora de diferentes hongos entomopatógenos sobre larvas del mosquito a nivel de laboratorio. Se evaluaron 16 aislamientos de hongos en diferentes concentraciones. Se constataron diferencias en el porcentaje de mortalidad producido en larvas de Cx. quinquefasciatus dependientes del tipo de aislamiento, de la concentración utilizada y del tiempo de exposición. Los aislamientos que presentaron el nivel de mortalidad más alto pertenecen a la especie Metarhizium anisopliae, seguidos por aislamientos de la especie Beauveria bassiana. El aislamiento que presentó el mayor nivel de mortalidad (100%) en menor tiempo de exposición (24 horas) fue Metarhizium anisopliae 99068 en una concentración de 1x106 e/ml. Por lo tanto este aislamiento es recomendado para su evaluación en campo y desarrollo de un producto comercial.


Author(s):  
Sean D. Moore

Thaumatotibia leucotreta, known as the false codling moth, is a pest of citrus and other crops in sub-Saharan Africa. As it is endemic to this region and as South Africa exports most of its citrus around the world, T. leucotreta has phytosanitary status for most markets. This means that there is zero tolerance for any infestation with live larvae in the market. Consequently, control measures prior to exporting must be exemplary. Certain markets require a standalone postharvest disinfestation treatment for T. leucotreta. However, the European Union accepts a systems approach, consisting of three measures and numerous components within these measures. Although effective preharvest control measures are important under all circumstances, they are most critical where a standalone postharvest disinfestation treatment is not applied, such as within a systems approach. Conventional wisdom may lead a belief that effective chemical control tools are imperative to achieve this end. However, we demonstrate that it is possible to effectively control T. leucotreta to a level acceptable for a phytosanitary market, using only biological control tools. This includes parasitoids, predators, microbial control, semiochemicals, and sterile insects. Simultaneously, on-farm and environmental safety is improved and compliance with the increasing stringency of chemical residue requirements imposed by markets is achieved.


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