Pest Mortality Research Articles

Biodiversity and pathogenicity of entomopathogenic fungi associated with the lesser spruce sawfly, Pristiphora abietina

AbstractOutbreaks of lesser spruce sawfly, Pristiphora abietina (Christ) (Hymenoptera: Tenthredinidae), on conifers regularly occur in Turkey and other European countries. Chemical pesticides have been used to contain outbreaks, but those may damage the forest and disturb natural enemies. To minimize the use of chemical pesticides in the management of this forest pest, we identified the entomopathogenic fungi (EPF) that naturally occur on P. abietina and tested their efficacy against the pest under laboratory and semi‐field conditions. Using morphological and molecular techniques, 13 EPF isolates were obtained from the pest and identified as Beauveria bassiana (Bals.‐Criv.) Vuill., Beauveria pseudobassiana S.A. Rehner & Humber, and Lecanicillium muscarium (Petch.) Zare & W. Gams. A laboratory screening test at 106 conidia ml−1 showed that all isolates caused 59‐100% mortality after 14 days. Further experiments were performed with the three most effective isolates, all belonging to B. bassiana. For these isolates, an increase in conidia dose increased pest mortality. Also, the ability of horizontal transmission in the pest population was shown. All three isolates were effective in killing P. abietina on spruce under semi‐field conditions. These data will contribute to the development of an integrated pest management program for P. abietina based on microbial biological control.

KHẢO SÁT HIỆU LỰC PHÒNG TRỪ SÂU TƠ (Plutella xylostella L.) CỦA DỊCH CHIẾT THÔ MỘT SỐ LOẠI THỰC VẬ

This study aimed to evaluate the effect of three types of plant extracts on pest mortality, pest chasing away effects, and antifeedant index. The results released that the rate of chasing diamondback moth reached 53.10% when spraying ginger-garlic-chili extract. This ratio when using the extracts from shallot and tomato leaves was respectively 31.48% and 27.80%. Similarly, with two other research criteria, the use of ginger-garlic-chili extract also brought the strongest efficiency when the pest mortality and antifeedant index were created 86.63% and 94.60%. Spraying the extracts of shallot and tomato leaves showed the low effects on the diamondback moth mortality at the rates of 50.25% and 40.65%. Besides, the antifeedant index of the pest was only 64.23% and 44.45% respectively when using the extracts from the shallot and tomato leaf. These results initially indicated that the ginger-garlic-chili extract had a positive effect on the prevention of diamondback moth.

Modeling of the toxicity of Eucalyptus globulus Labill essential oil against red flour beetle, Tribolium castaneum Herbst

Although the application of synthetic chemicals is the main method in the management of insect pests, their overuse has led to public concerns about environmental pollution, threats to human health, and acute and chronic toxicity on non-target organisms. Plant essential oils have introduced as healthy, available, and effective alternatives to detrimental chemicals in recent years. Further, it is necessary to predict the exact amount of required pesticide to save costs and determine the optimal conditions for achievement to the best outcomes. Accordingly, the toxicity of Eucalyptus globulus Labill essential oil against the adults of a cosmopolitan pest Tribolium castaneum Herbst (red flour beetle) along with its modeling and optimization was assessed using Response Surface Methodology (RSM). The coefficients of the essential oil concentration and time as independent variables are positive, showing their increase results in the augmentation of insect pest mortality. E. globulus essential oil showed prospective concentration-time dependent fumigant toxicity against T. castaneum. A quadratic polynomial equation was achieved for the toxicity of E. globulus essential oil using multiple regression analysis: 7.33413 + 0.20191A + 0.47313B + 4.64054E-003AB + 0.016349B2, in which A and B are the exposure time and essential oil concentration. The accuracy of the introduced model was approved through the analysis of variance. Results of the optimization indicated that 45.50 μl/l of essential oil and 72.00 h-exposure time would be adequate to achieve 92.45% mortality of T. castaneum. According to the results of current study, E. globulus essential oil has high potential in the management of T. castaneum and the Response Surface Methodology (RSM) is a suitable method to the optimization and modelling of this bio-effect.

High Potential of Liquid Smoke from Coconut Shell (Cocos nucifera) for Biological Control of Rice Bug (Leptocorisa oratorius Fabricius)

Rice bug (Leptocorisa oracorius F) is one of the most dangerous pests for paddy commodities (Oryza sativa) in the world. The use of liquid smoke was popular among local farmers to control rice bug. A coconut shell is the main source for making liquid smoke. This research aims to analyse rice bugs' mortality and antifeedant activity when dipped with coconut shell liquid smoke. The liquid smoke's effectiveness was measured by dipping paddy (5 grams in weight) that is previously soaked with coconut shell liquid for 20 seconds. The liquid smoke was prepared in various concentrations, ranging from 0% as a control; 0.50%; 0.75%; 1%; 1.25% and 1,50%. Observations were made at 24, 48, 72, 96, 120, 144 and 168 hours. Data analysis was performed by one-way ANOVA test, using SPSS program followed by a 0.05 Tukey test to determine the significance of the rice bug pest mortality. The study resulted that the mortality values from low concentrations to high concentrations were 40%, 46.67%, 60%, 70%, and 80% over seven days. The antifeedant percentage of liquid smoke increased from low concentrations to high concentrations respectively were 10.14%, 15.15%, 31.03%, 46.15%, and 68.88% during seven days. The concentration of liquid smoke that has the highest mortality was 1.50%. In conclusion, 1.50% of liquid smoke showed the highest percentage of mortality and antifeedant activity with 80% and 68.88%, respectively. In the future, it is hoped to develop this model for commercial consumption and reduce reliance on chemicals to control rice bugs. The use of pesticides can do more harm than good, especially to the environmental system

Sulfuryl fluoride as a methyl bromide alternative for fumigation of Necrobia rufipes (Coleoptera: Cleridae) and Tyrophagus putrescentiae (Sarcoptiformes: Acaridae), major pests of animal-based stored products

Sulfuryl fluoride (SF) has been registered in many countries for stored product applications as an alternative to other fumigants, especially methyl bromide (MB). Research was conducted to establish SF fumigation protocols for the mortality of pests infesting post-harvest durable commodities. The efficacy of SF against two major arthropod pests of southern dry-cured hams, the red-legged ham beetle, Necrobia rufipes, and the ham mite, Tyrophagus putrescentiae, was investigated. SF caused significant mortality in ham beetles but not for ham mites when treated for 48 h at 23 °C. Eggs of N. rufipes were more tolerant to SF than other stages fumigated. In addition, early aged (1–2 d old) eggs of N. rufipes were more susceptible to SF than late-aged (4–5 d old) eggs. Furthermore, SF fumigation led to 100% control of larvae, pupae and adults of N. rufipes by 8 g/m3 while the eggs required 20.88–24.72 g/m3 to prevent 100% hatch. However, T. putrescentiae showed high tolerance to SF as it survived concentration-time products in excess of the standard label limit 1500 g h/m3. SF studies also revealed that the eggs of T. putrescentiae were several fold more tolerant than that of the mobile stage, the nymphs and adults. SF trials under pilot-scale commercial conditions were also carried out that further supported the efficacy of SF for red-legged ham beetles but not for the ham mite. SF may not be suitable for managing ham mites based on work to date, but future work could investigate longer exposure times at higher temperatures.

Bacillus thuringiensis Effect on the Vegetative Development of Cotton Plants and the Biocontrol of Spodoptera frugiperda

Bacillus thuringiensis (Bt) is used worldwide as a tool for controlling lepidopteran pests. Recent studies have demonstrated the possibility of its use as an endophytic organism, controlling insects and promoting plant growth. In this aspect, strains of Bt toxic to lepidopteran pests were inoculated both onto seeds and into cotton plants and were assessed for effectiveness in controlling Spodoptera frugiperda and its effect on promoting plant growth. It was observed that the results obtained from the interaction between the Bt strains (S1450 HD-1, S1905, S2122, S2124) and the cotton genotypes (BRS 8H, BRS Aroeira and BRS 286) showed different growth responses. The results also showed that all the strains may not be suitable to explore the biological control mechanism without undermining plant health. Therefore, the strain S2122, the BRS 8H genotype and seed inoculation were selected to continue the tests by using two concentrations of the bacterium. The results of Bt strain inoculation in seeds and into cotton plants showed that, although plant height, number of leaves, and development stage were influenced by Bt inoculation, overall, there was no significant improvement in the plant growth. The plants that were inoculated with Bt also interfered in the weight of Spodoptera frugiperda, however, did not cause the pest mortality. The collected results suggest that there is a close relationship between the Bt strain and the cotton crop and that colonizing mechanism of the bacterium can be useful in situations that there is an inefficiency of the control measures, since the endophytic Bt makes the pest more susceptible to be controlled by other practices, improving management effectiveness.

Organic control of Bemisia tabaci Genn. on Capsicum annuum with entomopathogenic fungi raw secondary metabolites

Abstract. Soesanto L, Fatihah B, Manan A, Mugiastuti E, Prihaningsih N. 2020. Organic control of Bemisia tabaci Genn. on Capsicum annuum with entomopathogenic fungi raw secondary metabolites. Biodiversitas 21: xxxx. Control of whitefly with entomopathogenic fungi raw secondary metabolites and their correlation was investigated under control condition. The in vitro test used randomize completely design consisted of five treatments (raw secondary metabolites of Beauveria bassiana B16 and B10, Metarhizium anisopliae M16, Lecanicillium lecanii L16, and no treatments) and repeated five times. The in planta one used Latin square design consisted of five treatments and repeated five times. Variables observed were the mortality of whitefly imago, chitinolytic index, incubation period, viral disease intensity, plant height and total leaves per plant. The results showed that all treatment of raw secondary metabolites of entomopathogenic fungi caused mortality in the B. tabaci imago by 77.8% (B. bassiana B16); 71.5% (B. bassiana B10); 66.7% (M. anisopliae M16); and 59.5% (L. lecanii L16). All raw secondary metabolites of entomopathogenic fungi reduce the intensity of viral diseases by 79.98% (B. bassiana B16); 74.00% (B. bassiana B10); 72.23% (L. lecanii L16); and 55.41% (M. anisopliae M16). The correlation between B. tabaci mortality due to raw secondary metabolites of entomopathogenic fungi with the viral disease intensity is very close and opposite. Every 1% increase in pest mortality causes decrease in viral intensity by 1.346%.

DELPHINIUM LEPTOCARPUM NEVSKI AND DELPHINIUM PARADOXSUN BGE AS POTENTIAL SOURCES FOR PEST CONTROL IN CEREALS AND LEGUMES

In the present study, the insecticidal activity of plant extracts from the aerial parts of Delphinium leptocarpum Nevski and Delphinium paradoxsun Bge against two major important legume insect pests, cowpea weevils (Callosobruchus maculates) and the rice weevil (Sitophilus oryzae), was studied. According to the screening results, the insecticidal toxicity of the chloroform extract of plant D. leptocarpum N. showed LC50 value of 0,70 mg / mL for adult C. maculates, 0,81 mg / mL for S. oryzae, respectively. The toxicity of the alcoholic extract of D. paradoxsun B. is LC50 0,35 mg / mL for adult C. maculates, 0,39 mg/ mL for S. oryzae, respectively. Exposure to the chloroform extract of D. leptocarpum N. at concentration of 5-10 mg / mL for 24 hours resulted in 83.0100% mortality. After 48 h exposure, the pest mortality was 100%. Under the influence of an alcoholic extract of D. paradoxsun B. at dose of 5-10 mg /mL, the mortality of pests reached 99-100%. The probable use of extracts of D. leptocarpum N. and D. paradoxsun B.as bioinsecticides is discussed here.

Biological Agent’s Effectiveness For Control Of Diamondback Moth Larvae (Plutella xylostella Linn) With Different Population Levels On Lettuce

Tritip caterpillars (Plutella xylostella) are pests that cause damage and reduce lettuce production. Control of P. xylostella pests can be done using biological agents or synthetic insecticides. Synthetic chemical pesticides in the long term can be used for resistance and resurgence of pests. Biological agents of B. bassiana, Metarhizium sp., and Trichoderma sp. can be used as an alternative solution to controlling P. xylostella. Research to examine the use of biological agents using B. bassiana, Metarhizium sp. and Trichoderma sp. to control P. xylostella attacks at different levels of pest participation. The study was conducted from 19 September to 9 November 2018 in Sidomukti, Bandungan, Semarang. The study used a completely randomized 5x3 split-plot pattern design with 3 replications. The main plot is the type of biological agents: A1: B. bassiana, A2: Metarhizium sp., A3: Trichoderma sp., A4: Insecticide and A5: control. The subplot is the pest population level: B1 = 1 larvae/plant, B2 = 2 larvae/plant, and B3 = 3 larvae/plant. Data were analyzed using ANOVA and continued with Duncan's Multiple Range Test. The results showed that biological agents and insecticides increased pest mortality, the percentage of healthy leaves, decreased the percentage of damaged leaves, the level of pest defense, and reduced the yield of lettuce.

Metarhizium Anisopliae Challenges Immunity and Demography of Plutella xylostella.

Entomopathogenic fungi are naturally existing microbes, that can serve as a key regulator of insect pests in integrated pest management strategies. Besides having no hazardous effects on the environment, these entomopathogens are alternatives to synthetic insecticides that can control notorious insect-like Plutella xylostella, a destructive pest of cruciferous crops. Three different species of entomopathogenic fungi were evaluated before the selection (high larval mortality and least LC50) of Metarhizum anisopliae. The study was designed to investigate the mortality, development, and immune responses of P. xylostella when challenged with M. anisopliae, a naturally existing soil-borne entomopathogenic fungus. M. anisopliae resulted in high pest mortality by killing 93% of larvae. However, no statistically significant effect on hemocyte concentration was observed. The activity of enzymes (Phenoloxidase and Superoxide dismutase) and immune genes (Defensin, Spaetzle, Cecropin, Lysozyme, and Hemolin) did vary at different time points (24, 48, 72 and 96 h) after exposure to M. anisopliae. Disturbance in the biological cycles of P. xylostella was also detected, significantly shorter adult life span (8.11:6.87, M:F) and reduced fecundity (101 eggs/female) were observed along with disturbed larval and pupal duration. Results suggest that M. anisopliae can efficiently hinder the P. xylostella defense and developmental system, resulting in mortality and disturbed demography.

INFECTIVITY OF BEAUVERIA BASSIANA (BALSAMO) AGAINST TRIBOLIUM CASTANEUM (COLEOPTERA: TENEBRIONIDAE)

Tribolium castaneum is a major pest in wheat flour but can attack other processed foodstuffs. Control of these pests can be done in various ways, one of them by biological control using entomopathogenic fungus Beauveria bassiana. This study aims to determine the infectivity of B. bassiana entomopathogenic fungus against T. castaneum populations in the laboratory. The experiment was completed with random preparations, each preparation was repeated three times. Imago T. castaneum was sprayed with a conidia suspension of B. bassiana at a density of 106 and 107 conidia/mL on three different storage media namely PDA, rice, and corn media. Mortality was calculated based on the percentage of imago that died of B. bassiana fungi. One week observation showed the mortality of T. castaneum after the application of B. bassiana fungus was 55.33% with 107 conidia/mL in corn media. The highest spore density was found in rice media with an average of 10.53 x 106 conidia/mL. Meanwhile, the value of the results showed LC50 of 2.11 x 107 conidia/mL and the fastest LT50 in corn media was 5.31 days

BIOEFFICACY OF NEW SPECIES OF ENTOMOPATHOGENIC NEMATODE, STEINERNEMA DHARANAII (NEMATODA: RHABDITIDA: STEINERNEMATIDAE) AGAINST WHITEGRUB, HOLOTRICHIA RUSTICA (COLEOPTERA: SCARABAEIDAE)

The bioefficacy study of new native species of entomopathogenic nematode, Steinernema dharanaii (TFRIEPN-15) against root grubs Holotrichia rustica infecting Tectona grandis crop of forest nurseries of central India was taken up under controlled laboratory conditions. The grub of H. rustica when exposed to range of Infective Juveniles (IJs) numbers dose dependant relationship by 10-15- and 25-30-days old grubs. The younger grubs were more susceptible as compared to older ones. Minimum number of IJs, i.e. 300 Grub-1 causes 13.33% mortality in younger 6 days after the exposure, followed by 46.66% at the IJs population of 600 IJs Grub-1 mortality in older grubs at population of 600 IJs Grub-1 causes 26.66% mortality. IJs population of 900 to 3000 caused mortality ranging from 73.33 to 93.33% in younger grubs at par with each other (P>0.05). IJ population of above 6000 IJs caused 100.0% mortality in younger grub which was significantly superior (P<0.05). The older grub also exhibited similar trends, however maximum of 93.33% mortality at the highest IJ population. These experiments have proved that indigenous species of entomopathogenic nematodes can be used successfully control white grubs and other soil insect pests with eco-friendly and effective management techniques achieving cent-percent mortality of the target insect pests.

UJI EFEKTIVITAS BEBERAPA JENIS TANAMAN SEBAGAI PESTISIDA NABATI TERHADAP HAMA GUDANG Callosobrunchus sp

This research aimed to determine the effectiveness of pesticide plant leaves to the growth of warehouse pest (Callosobrunchus sp)and plant extracts that causes the highest mortality of warehouse pests (CallosobrunchusSp). The design used in this study was a Complete Randomized Block Design (CRBD) with the treatments used are PN0 (aquades), PN1 (Leeksextract), PN2 (extracts of Tagetes), PN3 (leaves Lemongrass Extract). Variable observations in this study are the toxins, contact poisons, nerve poison, repellent and antioviposit. The results showed that the extract of leaves of Tagetes, Lemongrass and Scallion effect on the growth of pest warehouse (Callosobrunchus sp) on observations of Toxins, contact poisons, a nerve poison, repellent and antioviposit. Leaves Tagetes extract is the right plant and effective towards mortality of warehouse pest (Callosobruschus Sp) at 80.89% of poisons contact, the nerve at 84,02%, and 85,05% of repellent activity, antioviposit at 97,6%.

Detrimental sublethal effects hamper the effective use of natural and chemical pesticides in combination with a key natural enemy of Bemisia tabaci on tomato

Bemisia tabaci (Hemiptera: Aleyrodidae) represents one of the greatest threats to agricultural crops. Chemical control is the primary tool used in integrated pest management (IPM) programs. However, release of the predator Nesidiocoris tenuis (Hemiptera: Miridae) on tomato plants is a highly recommended control tactic. The objective of this study was to evaluate the efficacy of a commercial borax plus citrus oil (BCO) product against B. tabaci in the presence and absence of N. tenuis. The synthetic insecticide lambda-cyhalothrin was used as a positive control. We also evaluated the sublethal effects of BCO on the behavior and predation rate of N. tenuis. Our results demonstrated that BCO, alone and at its maximum recommended field rate for B. tabaci, was not effective in controlling the pest under laboratory conditions. Application of BCO simultaneous with N. tenuis release did not reduce the increase in the B. tabaci population. Effective control of B. tabaci was achieved using only N. tenuis. However, synthetic lambda-cyhalothrin pyrethroid, used here as a control, caused high pest mortality and led to on-site extinction of N. tenuis, which did not occur for insects exposed to BCO. Lambda-cyhalothrin and BCO significantly affected the foraging behavior of N. tenuis, reducing the predation rate, especially following exposure to lambda-cyhalothrin. The insecticide lambda-cyhalothrin achieved satisfactory results in suppressing B. tabaci, but was harmful to N. tenuis. Additionally, lambda-cyhalothrin and BCO affected predator behavior. © 2020 Society of Chemical Industry.

Dynamics of populations of pine processionary moth (Thaumetopoea pityocampa) in the Republic of North Macedonia during the period 2007-2017

This study presents results for the dynamic of the populations of the pine processionary moth (Thaumetopoea pityocampa) during the period 2007-2017 and the impact of reducing factors in the Repub-lic of North Macedonia. The population density was determined by the number of larval nests both per tree and per hectare that varied during the research period. The number of individuals went up between 2007 and 2010, while during the following years it rapidly decreased. Since 2011, an overall prograding trend has been recorded in the several subsequent years. This could be explained by the huge number of individuals from the previous years that were in a diapause. The abundance of pest populations continued to grow in 2016 as no measures were taken. During the winter of 2016/2017, the impact of the extremely low temperatures on pest mortality was monitored in 2016-2017 generation. The density of the populations came to latency due to the very large number of dead larvae of second and third larval stages. We recorded a 100% mortality of larvae in plantations of Pinus nigra in the regions near Prilep, Sveti Nikole, Shtip, Kochani and Negotino Villages. &amp;nbsp;

PEMANFAATAN DAUN Theprosia vogelii DALAM PENGENDALIAN HAMA Sitophilus zeamays (Coleoptera : Curculionidae)

Sitophilus zeamays (Coleoptera: Curculionidae) is one of the pests that damage the corn kernels in storage so that it is damaged into corn powder. Control efforts that can be done is to use plant-based insecticides from Theprosia vogelii plants that contain rotenoid compounds so that they can cause pest mortality. The purpose of this study was to determine the effectiveness of Theprosia vogelli leaves in controlling Sitophilus zeamays in storage. The study was conducted at the Laboratory of the Faculty of Agriculture, University of Flores. The design used was a Completely Randomized Design (CRD) consisting of 5 treatments namely T0 = 0 gram (control), T1 (4 gram T. vogelii leaf powder), T2 (8 gram T. vogelii leaf powder), T3 (12 grams T. vogelii leaf powder) and T4 (16 grams of T. vogelii leaf powder). The observation variable was the mortality of the Sitophilus zeamays pest.&#x0D; The results showed that a dose of 16 grams of T. vogelii leaf powder caused a mortality of S. zeamays of 96.67%.&#x0D;

Nanobiopesticides: Silica nanoparticles with spiky surfaces enable dual adhesion and enhanced performance

AbstractBiopesticides, such as spinosad, are a new‐generation of ecofriendly pesticides in livestock industry. However, spinosad suffers from short duration of effectiveness and low potency in field conditions. Herein we report the development of a new nanospinosad design with dual adhesion and protection functions. Silica nanoparticles with spiky nanotopography loaded with spinosad possess rough surfaces. When applied topically, this nanospinosad formulation exhibited enhanced adhesion to both cattle hair and pest surface. The dual adhesion property led to significantly higher pest mortality toward tick (Rhipicephalus microplus, an ectoparasite) than a nanospinosad formulation using nanoparticles with smooth surface and a benchmark commercial product. The adhesion performance was further quantitatively measured using rainfastness test. Moreover, solar radiation test revealed that the nanospinosad exhibited &gt;10 times higher photostability over the commercial product. This work paves the way toward the development of high performance nanobiopesticides for sustainable agricultural applications.image

Synergy of Lepidopteran Nucleopolyhedroviruses AcMNPV and SpliNPV with Insecticides.

The joint use of baculoviruses and synthetic insecticides for integrated pest management requires the study of the additive, synergistic or antagonistic effects among them on pest mortality. Droplet bioassays were conducted with Autographa californica multiple nucleopolyhedrovirus (AcMNPV), Spodoptera littoralis nucleopolyhedrovirus (SpliNPV) and seven insecticides (azadirachtin, Bacillus thuringiensis, cyantraniliprole, emamectin, metaflumizone, methoxyfenozide and spinetoram) on Spodoptera exigua and Spodoptera littoralis. The lethal concentrations LC50 and LC95 were calculated through probit regressions. Then, the sequential feeding of insecticides and nucleopolyhedroviruses was studied. Larvae were provided with the LC50 of one insecticide, followed by the LC50 of one nucleopolyhedrovirus 24 h later. The inverse order was also conducted. The insecticide LC50 and LC95 were higher for S. littoralis than for S. exigua. AcMNPV showed greater toxicity on S. exigua than SpliNPV on S. littoralis. Emamectin showed synergy with AcMNPV when the chemical was applied first, and metaflumizone and AcMNPV were synergistic regardless of the order of application, both from the first day of evaluation. SpliNPV was synergistic with azadirachtin and emamectin when it was applied first, but synergy was reached after 12–13 days. Excellent control is possible with the LC50 of azadirachtin, emamectin and metaflumizone in combination with nucleopolyhedroviruses, and merits further study as a means of controlling lepidopteran pests.

Inaccessibility to double-stranded RNAs in plastids restricts RNA interference in Bemisia tabaci (whitefly).

RNA interference (RNAi) has emerged as a promising technology for insect pest control. Because of the accumulation of high levels of long double-stranded RNAs (dsRNAs) in plastids, it was previously shown that expression of dsRNAs from plastid genome led to higher mortality of some insect pests with chewing mouthparts than dsRNAs expression from nuclear genome. However, whether plastid-expressed dsRNAs have effects on phloem sap-sucking pests is unknown. In this study, we compared the RNAi effects of nuclear transgenic and transplastomic plants on the whitefly Bemisia tabaci, a serious sap-sucking pest. Nuclear transgenic and transplastomic tobacco plants were developed for the expression of dsRNA against BtACTB gene of Bemisia tabaci, respectively. Feeding nuclear transgenic plants to Bemisia tabaci resulted in reduced gene expression of BtACTB and survival rate, and impaired fecundity of Bemisia tabaci. We did not observe any effects of transplastomic plants on Bemisia tabaci fitness. Furthermore, we found that the inability of B. tabaci to obtain dsRNAs from plastids might restrict its RNAi responses. Our study indicated that the expression of dsRNAs in nuclear transgenic plants was more effective than that in transplastomic plants for the control of Bemisia tabaci. The inaccessibility of Bemisia tabaci to plastids contributes to the inefficiency of plastid-mediated RNAi. Our findings are of great significance to future optimization of transgenically delivered RNAi approaches for efficient controlling of sap-sucking pests. © 2020 Society of Chemical Industry.

Potentials of Grinting Grass (Cynodon dactylon l.) For Biopesticides On Sitophylus Zeamais Motsch Mortality

Corn is one of the cereals that has strategic and economic value and has the opportunity to be developed. The attack of the Sitophilus Zeamais Motsch species becomes one of the obstacles in the process of storing corn. This study aims to develop the potential of plant biopesticides from grinting grass to control the warehouse pests of Sitophilus Zeamais Motsch. This research is a laboratory based experimental study. The independent variables in this study were the gram weight of grinting grass extract and the number of Sitophilus Zeamais Motsch pests. The dependent variable in this study was the mortality of Sitophilus Zeamais Motsch. Grinting grass extract is obtained using maceration method. Qualitative and quantitative tests were carried out to test the active compound content of grinting grass. Vegetable biopesticide toxicity tests were carried out using a completely randomized design. The results showed that variations in the weight of grinting grass affect the content of chemical compounds present in the grass. Based on UV-Vis and FTIR spectra, the content of polyphenols, alkaloids, flavonoids, terpenoids, steroids, and saponins contains 20 gr / 100 mL, there are flavonoids as much, 2.38 mg / mL, saponins as 2.04 mg / mL, alkaloids as much as 1.79 mg / mL, polyphenols 3.15 mg / mL, steroids as much as 2.24 mg / mL and terpenoids as much as 3.15 mg / mL. Based on qualitative tests the active compound is evidenced by changes in color and deposition. While based on pest mortality tests, it was found that almost 50 percent of grinting grass extract can kill corn pests within a period of 7 days of observation with an extract concentration of 800 ppm.&#x0D; Key words: Biopesticides, Grinting Grass, Uv-Vis