Control Of Plutella Xylostella Research Articles

KOMPENTENSI PETANI DALAM PENGENDALIAN HAMA ULAT PERUSAK DAUN (Plutella Xylostella) PADA TANAMAN SAWI DI DESA JATI BALI KECAMATAN RANOMEETO BARAT KABUPATEN KONAWE SELATAN

The objective of this study is to evaluate the ability of farmers to control Plutella Xylostella pests on mustard plants in Jati Bali Village, Ranomeeto Barat Sub-district, South Konawe Regency. A qualitative approach was employed, with the research informants being mustard farmers in Jati Bali Village, selected using the Snowball Sampling method. Data was collected through observation, interviews, and documentation using an interview guide. The data analysis followed a qualitative method that involved four stages: data reduction, data presentation, verification, and conclusion drawing. The findings revealed that mustard farmers in Jati Bali Village primarily rely on synthetic pesticides for pest control. Farmers have demonstrated competence in pest control, as evidenced by their knowledge, attitudes, and skills in the farming process. However, their knowledge is limited to the use of chemical pesticides, and they lack sufficient understanding of other pest control methods, such as biological control, mechanical control, and disruption of the pest breeding cycle. Farmers who are involved in pest control should possess a positive attitude towards environmentally friendly pest control and have the necessary skills to apply different control methods effectively. By improving their knowledge, attitudes, and skills, farmers can adopt more diverse and sustainable pest control methods, which can reduce economic losses and negative environmental impacts.

Effect of Biocidal Substances on Population Dynamics of Plutella Xylostella Linnaeus, 1758, Auxiliary Insects, and Cabbage Production in the Suburban Area of Dakar

This study was conducted to determine the effects of biopesticides, used in the control of Plutella xylostella, major bioaggressor of cabbage, on its auxiliaries as well as on cabbage quality. It took place in a field of 65 m2, located in Malika, peri-urban area of Dakar. Treatments, based on Crateva religiosa (200g/l), Calotropis procera (400g/l), a mixture of the two products, and the control, were performed every two weeks on a random block device. Analysis of the results was done with the Rstudio software. Results showed that untreated plots were more infested with Plutella xylostella larvae (p-value = 0.01271). Efficacy of Calotropis procera on P. xylostella larvae has been demonstrated. The effect was all the more interesting since auxiliaries were not affected by treatments, as the regular sampling revealed. A satisfactory agronomic result was obtained at the end of this test, with as indicator, a much larger harvest from the treated plots.

Targeted delivery of emamectin benzoate by functionalized polysuccinimide nanoparticles for the flowering cabbage and controlling Plutella xylostella.

Plutella xylostella, one of the most destructive and cosmopolitan pests of cruciferous crops, is especially harmful to the young tissues of the flowering cabbage (Brassica campestris L.). Although emamectin benzoate (EB) has high insecticidal activity against P.xylostella, one major reason of low utilization for EB is the lack of internal transport in the young plants. In this study, four kinds of functional EB/polysuccinimide (PSI) with glycine methylester nanoparticles (EB@PGA NPs) were prepared. The obtained EB@PGA NPs could effectively protect EB from photolysis, and the degradation rate of EB@PGA NPs was <30% in 24 h. Simulating the intestinal pH=9 of P.xylostella, the highest cumulative release rate of EB@PGA NPs could reach 89.61% in 24 h. Furthermore, EB@PGA NPs could delivery EB into the young tissues of the flowering cabbage through the nanocarrier, and the highest transport efficiency of EB@PGA25 reached 1.437%. The bioactivity of EB@PGA25 against P.xylostella larvae (LC50 =0.34μg mL-1 ) was 1.6-fold higher than that of EB (LC50 =0.53μg mL-1 ). EB@PGA could easily become 'internalized' into the intestinal wall of P.xylostella, thus increasing the penetration of the drug and enhancing the insecticidal activity. The accurate delivery of insecticides by PGA nanocarriers into young tissues of plants could be a promising new method for the efficient management of field pests and diseases. © 2021 Society of Chemical Industry.

Spatio-Temporal Profiling of Metarhizium anisopliae-Responsive microRNAs Involved in Modulation of Plutella xylostella Immunity and Development.

Metarhizium anisopliae, a ubiquitous pathogenic fungus, regulates a wide array of the insect pest population. The fungus has been employed to control Plutella xylostella, an insecticide-resistant destructive lepidopteran pest, which causes substantial economic losses in crops worldwide. Integration of modern gene-silencing technologies in pest control strategies has become more crucial to counter pesticide-resistant insects. MicroRNAs (miRNA) play essential roles in the various biological process via post-transcriptional gene regulation. In the present study, RNA-seq analysis of control (CK36h, CK72h) and fungal-infected (T36h, T72h) midguts was performed to reveal underlying molecular mechanisms occurring in larval midgut at different time courses. We aimed at exploring M. anisopliae-responsive miRNAs and their target genes involved in development and immunity. After data filtration, a combined set of 170 miRNAs were identified from all libraries. Interestingly, miR-281, miR-263, miR-1, miR-6094 and miR-8 were listed among the most abundantly expressed conserved miRNAs. Furthermore, we experimentally studied the role of differentially expressed miR-11912-5p in regulating corresponding target trypsin-like serine proteinase (Px_TLSP). The luciferase assay (in vitro) revealed that miRNA-11912-5p significantly downregulated its target gene, suggesting it might play a crucial role in defense mechanism of P. xylostella against M.+ anisopliae infection. We used synthetic miRNA mimic/inhibitor (in vivo), to overexpress/silence miRNA, which showed harmful effects on larval duration, survival and adult fecundity. Additionally, fungal application in the presence of mimics revealed enhanced sensitivity of P. xylostella to infection. Our finding provides an insight into the relatively obscure molecular mechanisms involved in insect midgut during the fungal infection.

EFIKASI FREKWENSI PEMBERIAN DAN KONSENTRASI BIOSIDA EKSTRAK MIMBA UNTUK ALTERNATIF PENGENDALIAN HAMA Plutella xylostella L. PADA TANAMAN KAILAN (Brassica olearacea kvr. alboglabra)

The reseacrh entitled the effectiveness of application of frequency and concentration of neem extract bioside for alternative pest control Plutella xylostella l. on Kailan (Brassica oleracea kvr. alboglabra) plants. The aims of this study were to determine: 1. the interaction between the frequency of application and the concentration of neem leaf extract biocides against Plutella xylostella attacks on kailan plants, 2. the effect of the frequency of application of neem leaf extract biocides on Plutella xylostella, and 3) the effect of concentration neem leaf extract biocide against Plutella xylostella. This research was conducted using a completely randomized design (CRD) consisting of 2 factors and repeated three times. Factor I is the frequency of application of neem leaf extract biocide (F) consisting of 2 levels, namely: F1: one time application; F2: two times application. Factor II is the biocide concentration of neem leaf extract (K) consisting of 4 levels, namely: K0: Without neem leaf extract; K1: neem leaf extract 100 g/L water; K2: neem leaf extract 200 g/L; K3: neem leaf extract 300 g/L. The results of the research are as follows: 1). There was an interaction between the frequency of application and concentration of neem leaf extract biocides on total larval mortality, pest mortality percentage, and number of imago, 2) The frequency of application of neem extract biocides was significantly different on the level of pest attack at the 3, 4, 5 and 7 days after application, but not significantly different on the number of larval deaths, 3) The concentration of neem extract biocides significantly different on the level of pest attack at the 2, 3, 4, 5, 6 and 7 days after application, and the amount larval mortality at the time of observation 2-10 hours after application, 4) Neem leaf extract biocide was very effective in killing P. xylostella larvae 96-98% on the 7th day after application.

Metal-organic framework nanohybrid carrier for precise pesticide delivery and pest management

Smart core–shell nanocarriers can release pesticides in response to stimuli from the microenvironment associated with pests and the physiological behaviors of protected crops. In this work, a smart nanocarrier (MIL-101(Fe)@silica) with dual functions of site-specific delivery and plant nutrition was fabricated to deliver chlorantraniliprole (CAP) for sustainable pest management. The results showed that the developed CAP@MIL-101(Fe)@silica with a size of approximately 270 nm had a stable core–shell nanostructure with a highly crystallized regular octahedron. The photostability of the drug loaded in the carrier under UV-light irradiation was 16.5 times higher than that of technical CAP. The introduction of the silica shell prevented the premature escape of CAP from the MIL-101(Fe) core in the environment and endowed the developed nanohybrid carrier with base-triggered release properties. In a laboratory bioassay, CAP@MIL-101(Fe)@silica had favorable insecticidal activity (LC50 = 0.389 mg/L) in controlling Plutella xylostella larvae. After fourteen days of spraying in the greenhouse experiment, the mortality of the CAP@MIL-101(Fe)@silica treatment (86%) against P. xylostella larvae was significantly higher than that of the CAP suspension concentration treatment (36.7%). In addition, MIL-101(Fe)@silica was safe for crops and could enhance the crop fresh weight and dry weight by 18.6–19.6% and 4.8–17.7%, respectively. Therefore, MIL-101(Fe)@silica could be used as a biocompatible carrier for site-specific pesticide delivery and simultaneously as a fertilizer for crop growth, which would be a novel route for the development of a precise pesticide delivery nanoplatform.

Opuntia ficus-indica cladode extract is an embryotoxic, larvicidal, and oviposition-deterrent agent for the diamondback moth, Plutella xylostella

The search for new compounds to control Plutella xylostella, the main pest of Brassica crops, has been stimulated by the environmental impact of the insecticides currently used and reports of resistant populations. This work evaluated the effects of a cladode extract from Opuntia ficus-indica (CE) on the survival and development of P. xylostella, as well as on its oviposition behavior. Additionally, the effects on the histological organization of the larval midgut, as well as digestive enzyme activities, were evaluated. CE contained flavonoids, cinnamic derivatives, terpenes, steroids, and reducing sugars. High-performance liquid chromatography analysis confirmed the presence of rutin and compounds containing aliphatic chains and aromatic rings in their structures. CE reduced the viability of eggs with an EC50 (concentration that reduces egg viability by 50%) at 5.37% (w/v) and killed larvae with an LC50 (concentration that kills 50% of larvae) at 7.75% (w/v). Histological analysis revealed several alterations in the midgut of larvae exposed to the extract, including the presence of spherites, cell nuclei expulsion, the disappearance of the peritrophic membrane, and an increase in the number of goblet cells. CE inhibited the in vitro activity of proteases from larvae midgut extracts. The extract also presented oviposition-deterrent activity. In conclusion, cladodes of O. ficus-indica are a source of compounds toxic to eggs and larvae of P. xylostella and are able to interfere with oviposition site choice. The results suggest potential of CE as a botanical insecticide, though field trials are needed to confirm activity.

Effectiveness of vermicompost with additives of various botanical pesticides in controlling Plutella xylostella and their effects on the yield of cabbage (Brassica oleracea L.var. Capitata)

Effectiveness of vermicompost with additives of various botanical pesticides in controlling Plutella xylostella and their effects on the yield of cabbage (Brassica oleracea L.var. Capitata)

Residue behavior and dietary risk assessment of spinetoram (XDE-175-J/L) and its two metabolites in cauliflower using QuEChERS method coupled with UPLC-MS/MS

Spinetoram (XDE-175-J/L), a new spinosyn-based insecticide, is one of the most widely used bio-pesticide worldwide and its registration for direct application on cauliflower to control Plutella xylostella is currently under review in China. In this study, an accredited method for simultaneous determination of spinetoram and its two metabolites in cauliflower was established and validated using QuEChERS (quick, easy, cheap, effective, rugged, and safe) preparation coupled with ultra-liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The average recoveries using this method were ranged from 74 to 99% with relative standard deviations (RSDs) of 2.4–10.5%. The dissipation kinetics and terminal residues of spinetoram and its two metabolites in cauliflower were studied in Tianjin and Guizhou over two years under open field conditions. The dissipation experiments revealed that spinetoram was swiftly degraded in cauliflower, with the half-lives less than or equal to 4.85 days. The terminal residues of total spinetoram (sum of spinetoram and its two metabolites) detected in cauliflower samples were in the range of 0.009 mg/kg-0.337 mg/kg. Dietary risk assessment study was implemented based on the scientific data of field trials, food consumption and acceptable daily intake (ADI). The estimated long-term dietary risk probability (RQ) of total spinetoram from cauliflower was between 5.79% and 5.91%, indicating that spinetoram was associated with acceptable risk for dietary cauliflower consumption. The results would provide scientific guidance for proper usage of spinetoram in cauliflower field ecosystem.

Fabrication of smart stimuli-responsive mesoporous organosilica nano-vehicles for targeted pesticide delivery

It is highly desirable to construct stimuli-responsive nanocarriers for improving pesticides targeting and preventing the pesticides premature release. In this work, a novel redox and α-amylase dual stimuli-responsive pesticide delivery system was established by bonding functionalized starch with biodegradable disulfide-bond-bridged mesoporous silica nanoparticles which loaded with avermectin (avermectin@MSNs-ss-starch nanoparticles). The results demonstrated that the loading capacity of avermectin@MSNs-ss-starch nanoparticles for avermectin was approximately 9.3 %. The starch attached covalently on the mesoporous silica nanoparticles could protect avermectin from photodegradation and prevent premature release of active ingredient. Meanwhile, the coated starch and disulfide-bridged structure of nanoparticles could be decomposed and consequently release of the avermectin on demand when nanoparticles were metabolized by glutathione and α-amylase in insects. The bioactivity survey confirmed that avermectin@MSNs-ss-starch nanoparticles had a longer duration in controlling Plutella xylostella larvae compared to avermectin emulsifiable concentrate. In consideration of the superior insecticidal activity and free of toxic organic solvent, this target-specific pesticide release system has promising potential in pest management.

UJI EFIKASI INSEKTISIDA BAHAN AKTIF PERMETRIN 300 g/l TERHADAP POPULASI HAMA ULAT DAUN (Plutella xylostella L) PADA TANAMAN KUBIS (Brassica oleracea)

Cabbage plants (Brassica oleracea) are one of the vegetables that are widely cultivated by farmers in Indonesia, both in the highlands and lowlands. Cabbage plants are usually cultivated at the beginning of the dry season. Cabbage has high production potential and its marketing is relatively easy. So that it is right if the cabbage is prioritized as one of the leaf vegetable plants that needs to be further developed. Cabbage production in the last six years shows a trend of fluctuations every year. Production in 2012 increased by 0.14% to 7,550,021 tons from 7,539,533 tons, then increased by 1.95% to 7,469,013 tons in 2013, and decreased 3.06% to 7,461,697 tons in 2014, then in 2015 it decreased 2.62% to 7,265,840 tons, then in 2016 the production increased to 7,274,126 tons and subsequently in 2017 it increased 2.64%. Fluctuations in cabbage production are inseparable from the effect of an increase or decrease in the area of harvest and the attack of plant pests. The aim of this study was to determine the most effective concentration of the active ingredient of Permethrin 300 g/l to control Plutella xylostella L caterpillar pest in cabbage plants. This research was conducted in Sudimoro Village, Teras Subdistrict, Boyolali Regency at an altitude of 196 m above sea level with alluvial brown soil types, with soil solum thickness &gt; 90 cm. Based on the Oldeman classification, Sudimoro Village is a D3 zone, with a wet month length of 3-4 months and a dry month length of 3-6 months. The method used in the study was a non factorial Complete Group Randomized Design (RAKL) with 5 (five) different concentrations of insecticide treatments. The concentration treatments used were 1 cc/ liters (C1), 0.75 cc/ liters (C2), 0.5 cc/ liters (C3), 0.25 cc/ liters (C4), and control (C5). The results showed that the treatment of the active ingredient concentration of insecticide Permethrin 300 g/l had a very significant effect on the parameters of the Plutella xylostella L population, the weight of the wet stover, the weight of the crop, and the diameter of the crop. However, it does not significantly affect the parameters of plant height and dry stover weight.The effectiveness of the active ingredient insecticide Permethrin 300 g/l in the parameters of the population of Plutella xylostella L is best in the treatment concentration of 0.75 cc/ liters (C2), with a 100% efficacy rate.

Keberhasilan hidup parasitoid Diadegma semiclausum Hellen dan serangga inangnya Plutella xylostella (L.) terhadap aplikasi ekstrak biji srikaya (Annona squamosa L.)

Pengendalian Plutella xylostella L. dapat dilakukan baik secara hayati maupun kimiawi. Pengendalian secara hayati umumnya banyak dilakukan dengan cara memanfaatkan ekstrak tanaman untuk membunuh serangga hama. Penelitian ini bertujuan mengetahui pengaruh ekstrak biji srikaya terhadap kematian dan perkembangan parasitoid Diadegma semiclausum Hellen serta inangnya, P. xylostella. Pengaruh ekstrak biji srikaya terhadap larva P. xylostella instar III awal diuji dengan metode residu pada daun dan metode residu pada permukaan gelas untuk menguji pengaruh kontak ekstrak biji srikaya terhadap kematian imago D. semiclausum. Pengaruh ekstrak biji srikaya terhadap parasitisasi dan perkembangan D. semiclausum pradewasa dilakukan dengan memaparkan larva P. xylostella yang telah terkontaminasi ekstrak biji srikaya pada konsentrasi subletal (LC5 dan LC10) pada imago D. semiclausum. Hasil penelitian menunjukkan ekstrak biji srikaya pada konsentrasi 0,0632–0,1% pada kontaminasi 24 jam berpengaruh terhadap kematian larva P. xylostella dan imago parasitoid D. semiclausum. Imago parasitoid lebih peka terhadap peningkatan konsentrasi ekstrak biji srikaya dibandingkan dengan larva P. xylostella. Hambatan perkembangan P. xylostella oleh ekstrak biji srikaya pada konsentrasi yang digunakan umumnya tidak nyata. Demikian pula, hambatannya terhadap perkembangan parasitoid D. semiclausum dalam inang yang terkontaminasi konsentrasi subletal (LC5 dan LC10) ekstrak biji srikaya umumnya tidak berbeda nyata. Keberadaan ekstrak biji srikaya dalam inang juga tidak berpengaruh nyata terhadap tingkat parasitisasi, panjang kokon, lebar kokon, dan bobot kokon. Oleh karena itu, terdapat peluang memadukan pengendalian P. xylostella secara kimiawi dan hayati.

BUDIDAYA TANAMAN MAHONI (Sweitenia macrophylla) DAN PEMANFAATANNYA SEBAGAI TANAMAN OBAT

Batukau Mount with its dense forest as the lungs of Tabanan Regency. As a buffer zone, water sources can irrigate existing subak, one of them is Jatiluwih Subak which is a World Cultural Heritage. At the south foothill of Mount Batukau Mount there is Sad Kahyangan Temple, Batukau Temple. Nature preservation around the temple is still maintained, but over time there are areas that need to be greened. Based on this situation, community service around Batukau Temple is carried out with the theme "Mahogany Cultivation (Sweitenia macrophylla) and Its Use as Medicinal Plants". The community service method was carried out with a lecture system to several community members in Batukau Temple. Conclusions obtained in the cultivation of mahogany plants that need to be considered are hatcheries and nurseries, planting and maintenance. As a medicinal plant, mahogany seed extract can be used as an environmentally friendly vegetable pesticide to control Plutella xylostella and Crosidolomia binolalis in cabbage when pests were in the larval stage and seeds of mahogany fruit contain various substances including flavonoids and saponins that function as bacteriocytes.&#x0D; Key Word : cultivation, Mahogany plant, medicinal plants

Chemical Compounds and Bioactivity of Aqueous Extracts of Alibertia spp. in the Control of Plutella xylostella L. (Lepidoptera: Plutellidae).

Successive applications of insecticides to control Plutella xylostella L. (Lepidoptera: Plutellidae) have resulted in the emergence of resistant populations of this insect. A novel control measure for this target insect could be the use of botanical insecticides derived from plant tissues. Hence, we experimentally tested aqueous extracts of Alibertia edulis (Rich.), Alibertia intermedia (Mart.), and Alibertia sessilis (Vell.) K. Schum. found in the Brazilian savannah in order to investigate their potential to disrupt the life cycle of P. xylostella. Aqueous extracts of the leaves of A. intermedia and A. sessilis negatively affected the development of P. xylostella in all stages of the life cycle, prolonging the larval stage and causing mortality in the larval or pupal stages. Treatments with A. intermedia and A. sessilis extracts caused the lowest fecundity and the number of hatched larvae. The harmful effects of these aqueous extracts on the life cycle of P. xylostella may be attributable to the flavonoids and other phenolic compounds present in A. intermedia and A. sessilis. These aqueous botanical extracts are low in toxicity when compared to non-aqueous pesticides, and may emerge as an effective approach for control of populations of P. xylostella.

Expression and inheritance of Bt cry1Ia8 gene in transgenic cabbage to control Plutella xylostella

We previously transformed cabbage plants with a Bacillus thuringiensis cry1Ia8 gene. The resulting transgenic plants were able to control both susceptible and Cry1Ac-resistant Plutella xylostella larvae. For practical applications, transgenes should be inherited in a stable and predictable manner. To evaluate and characterize the stability of transgenic cabbages produced using an Agrobacterium tumefaciens-mediated transformation procedure, transgene expression and inheritance were examined in four single-copy lineages (A14-3, A14-5, A14-7, and A14-8) and their sexually derived progenies. Segregations ratios (insect-resistant:insect-sensitive) of 2.56:1, 2.75:1, 3.24:1, and 1.6:1 were observed in the T1 generation of lineages A14-3, A14-5, A14-7, and A14-8, respectively. Examinations of Cry1Ia8 activities in the T1, T2, and T3 plants indicated transgene inheritance followed the Mendelian segregation pattern in lineages A14-3, A14-5, and A14-7. Southern blot and enzyme-linked immunosorbent assay analyses of the T0, T1, T2, and T3 progenies revealed that the transgene was successfully inserted into the cabbage genome, and had been transmitted to self-pollinated T3 progenies. These results imply that the homozygous transgenic lines exhibiting stable inheritance of the transgene and can be used effectively in breeding programs.

Cry Proteins from Bacillus thuringiensis Active against Diamondback Moth and Fall Armyworm.

Biopesticides based on Bacillus thuringiensis and genetically modified plants with genes from this bacterium have been used to control Plutella xylostella (L.) and Spodoptera frugiperda (J.E. Smith). However, the selection pressure imposed by these technologies may undermine the efficiency of this important alternative to synthetic insecticides. Toxins with different modes of action allow a satisfactory control of these insects. The purpose of this study was to characterize the protein and gene contents of 20 B. thuringiensis isolates from soil and insect samples collected in several areas of Northeast Brazil which are active against P. xylostella and S. frugiperda. Protein profiles were obtained by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Polymerase chain reaction assays were used to determine toxin genes present within bacterial isolates. The protein profile of the majority of the isolates produced bands of approximately 130kDa, suggesting the presence of Cry1, Cry8 and Cry9 proteins. The gene content of the isolates of B. thuringiensis investigated showed different gene profiles. Isolates LIIT-4306 and LIIT-4311 were the most actives against both species, with LC50 of 0.03 and 0.02 × 10(8)sporesmL(-1), respectively, for P. xylostella, and LC50 of 0.001 × 10(8)sporesmL(-1) for S. frugiperda. These isolates carried the cry1, cry1Aa, cry1Ab, cry1Ac, cry1B, cry1C, cry1D, cry1F, cry2, cry2A, cry8, and cry9C genes. The obtained gene profiles showed great potential for the control of P. xylostella and S. frugiperda, primarily because of the presence of several cry1A genes, which are found in isolates of B. thuringiensis active against these insects.

Attractive Effects Efficiency of LED Trap on Controlling Plutella xylostella Adults in Greenhouse

This study was conducted to determine the attractive effects of Plutella xylostella adults to light emitting diode (LED) trap in greenhouse and compared with those of no light trap and black-light which is typically used in commercial luring lamp. The green LED trap captured more P. xylostella when compared with black-light trap, whereas the no light trap was a little attractive to P. xylostella adults. These results indicated that the green LED traps could be used for environmental insect pest control.

Evaluation of the time-concentration-mortality responses of Plutella xylostella larvae to the interaction of Isaria fumosorosea with the insecticides beta-cypermethrin and Bacillus thuringiensis

Entomopathogenic fungi are potential candidates for controlling Plutella xylostella, a cosmopolitan pest of crucifers. In this study, bioassays were conducted to evaluate the interaction between Isaria fumosorosea and sublethal doses of two insecticides, beta-cypermethrin and Bacillus thuringiensis, against P. xylostella. Data of each assay were in good agreement with the time-concentration-mortality model, indicating a strong dependence of the fungus and insecticide interaction on both concentration and post-exposure time. Using beta-cypermethrin 58-116 µg mL(-1) or B. thuringiensis 222.5-890 µg mL(-1) with the fungus significantly enhanced fungal efficacy. The LC50 values of the fungus declined over a 1-7 day period after exposure, and the LT50 values decreased with increasing concentration. Based on LC50 or LC90 estimates, synergism between the fungus and beta-cypermethrin resulted in a 2.7-28.3-fold reduction in LC50 values and a 12.1-19.6-fold reduction in LC90 values, while synergism of the fungus with B. thuringiensis led to a 2.4-385.0-fold reduction in LC50 values and a 4.4-151.7-fold reduction in LC90 values. Results show that sublethal doses of B. thuringiensis and beta-cypermethrin can synergise I. fumosorosea activity on P. xylostella, suggesting that combination of I. fumosorosea with the two insecticides might offer an integrated approach to controlling P. xylostella in practice. © 2014 Society of Chemical Industry.

Development of a New Method To Prepare Nano-/microparticles Loaded with Extracts of Azadirachta indica, Their Characterization and Use in Controlling Plutella xylostella

Biodegradable nanoparticles have been widely explored as carriers for controlled delivery of therapeutic molecules; however, studies describing the development of nanoparticles as carriers for biopesticide products are few. In this work, a new method to prepare nanoparticles loaded with neem (Azadirachta indica) extracts is presented. In this study, nanoparticles were formulated as colloidal suspension and (spray-dried) powder and characterized by evaluating pH, particle size, zeta potential, morphology, absolute recovery, and entrapment efficiency. A high-performance liquid chromatography method was used for nanoparticle characterization. The best formulations presented absolute recovery and entrapment efficiencies of approximately 100% and a release profile based on swelling and relaxation of the polymer or polymer erosion. The biological data of the formulated products against Plutella xylostella showed 100% larval mortality. The nanoparticle information improved the stability of neem products against ultraviolet radiation and increased their dispersion in the aqueous phase.

A Simple Method for Estimating Instantaneous Levels of Endoparasitism ofPlutellaxylostella(Linnaeus) (Lepidoptera: Plutellidae) by Hymenoptera in the Field

Although endoparasitoids are widely used for biological control of Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae) throughout the world, current methods do not allow for easy estimation of parasitism levels. I investigated the potential of using ratios of parasitoid cocoons to infestations to develop a simple and practical method of estimating parasitism levels in the field. Crop infestations by the pest and densities of its endoparasitoids' cocoons were recorded at weekly intervals over six consecutive years on unsprayed cabbage. In order to establish if there was a relationship between parasitism levels and ratios of parasitoid cocoons to infestations, samples of host larvae and pupae were collected every week during scouting for rearing in the laboratory. The majority of parasitoid cocoons belonged to the larval endoparasitoid Cotesia vestalis (Haliday) (Hymenoptera: Braconidae), which was the major mortality factor of P. xylostella. Total parasitism levels were positively related to ratios of parasitoid cocoons to infestations. Crop infestation by P. xylostella was low during periods of high parasitism (≥50 %) than during low parasitism (< 50 %), and 50 % parasitism corresponded with 20 % ratio of parasitoid cocoons to infestations. This study shows that ratios of parasitoid cocoons to infestations can be used to estimate background parasitism levels.