The Biological Control of Pests Research Unit (BCPRU) conducts research on developing biological and environmentally-friendly pest management methods. It works on mass production and delivery of beneficial organisms, as well as classical biocontrol of invasive pests. Current research includes rearing economically important insect species, identifying compounds for invasive ant control, and using pathogens to manage invasive plants. The BCPRU is working to improve mass production methods for predatory mites and ladybird beetles to control spider mites and aphids. It is also studying the social immunity of fire ants to identify better biological control agents, and developing methods to microencapsulate the fungus Trichoderma for controlling insect pests.
Introduction, Techniques of release of natural enemies, Recovery evaluation of released natural enemies for colonization, Survivorship analysis/ Prediction of Success of released natural enemies for colonization, Conservation of Natural Enemies, Augmentation of Natural Enemies, Ecological manipulations for colonization of natural enemies and colonized natural enemies, Large scale production of bio-control agents.,
Introduction, Techniques of release of natural enemies, Recovery evaluation of released natural enemies for colonization, Survivorship analysis/ Prediction of Success of released natural enemies for colonization, Conservation of Natural Enemies, Augmentation of Natural Enemies, Ecological manipulations for colonization of natural enemies and colonized natural enemies, Large scale production of bio-control agents.,
Communication in Insects.
Classification of Semiochemicals.
Introduction to Insect Pheromones.
Uses of Insect Pheromones.
Synthesis of Insect Pheromones.
Use of pheromones in insect pest management.
Honey bees are social insects, which means that they live together in large, well-organized family group.
Communication, complex net construction, environmental control, defense and divison of the labor are just some of the behaviour that honey bees have developed to exist successfully in social colonies.
A honey bees colony typically consists of three kinds of the bees 1) Queen. 2) Workers. 3) Drones.
In addition to thousands of workers adults, a colony normally has a single queen & several hundred drones.
Honey bees live in comb or nest.
Mutual cooperation exist.
Developed communication Dance.
routes of enterence of pollutants inaquatic ecosystemimranrohi56
Of the major routes of contamination for the aquatic environment, the most significant are directly from treated and untreated waste waters, run-off and atmospheric deposition (including spray drift) and indirectly from leaching.rinking water is derived from either surface waters or groundwater. The latter is of enormous importance, with more than 65% of Europe's drinking water needs being supplied in this way. However, water from either source is rarely, if ever, pure. Industrialization and urbanization together with intensified agricultural activity have led to increased demands for water on the one hand but to the potential for large scale release of contaminants on the other. The result is that surface water can be contaminated through direct or indirect emissions and groundwater can be contaminated by leaching from the soil. The diversity and number of existing and potential sources of chemical contamination are quite large.
Insecticides with growth regulating properties (IGR) may adversely affect insects by
regulating or inhibiting specific biochemical pathways or processes essential for insect
growth and development. Some insects exposed to such compounds may die due to abnormal
regulation of hormone-mediated cell or organ development. Other insects may die either from
a prolonged exposure at the developmental stage to other mortality factors (susceptibility to
natural enemies, environmental conditions etc) or from an abnormal termination of a
developmental stage itself. Insect growth regulators may come from a blend of synthetic
chemicals or from other natural sources, such as plants. The chemical composition of
hormones indigenous to insects is now being studied and used as a basis for developing
analogues or mimics against insects. The similarities, however, in certain aspects of
biochemistry among vertebrates and invertebrates may result in the limited development of
IGRs.
Communication in Insects.
Classification of Semiochemicals.
Introduction to Insect Pheromones.
Uses of Insect Pheromones.
Synthesis of Insect Pheromones.
Use of pheromones in insect pest management.
Honey bees are social insects, which means that they live together in large, well-organized family group.
Communication, complex net construction, environmental control, defense and divison of the labor are just some of the behaviour that honey bees have developed to exist successfully in social colonies.
A honey bees colony typically consists of three kinds of the bees 1) Queen. 2) Workers. 3) Drones.
In addition to thousands of workers adults, a colony normally has a single queen & several hundred drones.
Honey bees live in comb or nest.
Mutual cooperation exist.
Developed communication Dance.
routes of enterence of pollutants inaquatic ecosystemimranrohi56
Of the major routes of contamination for the aquatic environment, the most significant are directly from treated and untreated waste waters, run-off and atmospheric deposition (including spray drift) and indirectly from leaching.rinking water is derived from either surface waters or groundwater. The latter is of enormous importance, with more than 65% of Europe's drinking water needs being supplied in this way. However, water from either source is rarely, if ever, pure. Industrialization and urbanization together with intensified agricultural activity have led to increased demands for water on the one hand but to the potential for large scale release of contaminants on the other. The result is that surface water can be contaminated through direct or indirect emissions and groundwater can be contaminated by leaching from the soil. The diversity and number of existing and potential sources of chemical contamination are quite large.
Insecticides with growth regulating properties (IGR) may adversely affect insects by
regulating or inhibiting specific biochemical pathways or processes essential for insect
growth and development. Some insects exposed to such compounds may die due to abnormal
regulation of hormone-mediated cell or organ development. Other insects may die either from
a prolonged exposure at the developmental stage to other mortality factors (susceptibility to
natural enemies, environmental conditions etc) or from an abnormal termination of a
developmental stage itself. Insect growth regulators may come from a blend of synthetic
chemicals or from other natural sources, such as plants. The chemical composition of
hormones indigenous to insects is now being studied and used as a basis for developing
analogues or mimics against insects. The similarities, however, in certain aspects of
biochemistry among vertebrates and invertebrates may result in the limited development of
IGRs.
Biological Control to Maintain Natural Densities of Insects and Mites by Fiel...Premier Publishers
In the present study, the biological control of insects and mites to maintain their natural densities by field releases of lady beetles (Coleoptera: Coccinellidae) is analyzed. Female lady beetles may lay from 20 to more than 1000 eggs over a one to three month period, near prey such as aphids in protected sites on leaves and stems. Lady beetles have hefty appetites and one tiny alligator like larva can eat over two dozen aphids a day, and single adult can eat over twice of that much. In other words, one larva will eat about 400 medium-size aphids during its development to pupal stage and an adult lady beetle may eat over 5,000 aphids during its lifetime (about a year). Usually, reddish-orange lady beetles eat aphids, and darker ones more often eat spider mites, whiteflies and scale insects. The best time to release lady beetles into garden is late in afternoon or at sundown, which can encourage them to stay for night and find suitable food and protection. Dampen the ground or plants before releasing of lady beetles, can encourage them to stay and drink water. About 1000 lady beetles can rid an acre of ground from most of soft-bodied pests and release beetles at base of plants at 20 feet apart or more so that they can hunt for food. Ability of collected lady beetles to reproduce is suspended (reproductive diapause), so eggs are not produced for several weeks after release. Pre-fed lady beetles prior to release can allow some eggs maturation, but few researchers or companies also provide such pre-conditioned lady beetles. The trends of prey devouring demonstrate profound effects that lady beetle may have on target and non-target pests, and highlight their importance for initiating of biological control programs.
Wheat-pea intercropping for aphid control: from laboratory tritrophic approac...InternationalNetwork
Intercropping is an interesting practice to promote the sustainable control of insect pests such as aphids. In particular, volatile organic compounds emitted by aphid-infested intercropped plants may deter other aphid species from their host plants, while attracting natural enemies. In this study, olfactometer and net-cage behavioural assays were first conducted to determine the effect of wheat-pea mixtures combined with aphid infestations on odour preferences of the wheat aphid Sitobion avenae and two associated predator species, the ladybird Harmonia axyridis and the hoverfly Episyrphus balteatus. Healthy wheat plants were preferred by S. avenae, while wheat-pea mixtures combined with aphid infestations were significantly less attractive. H. axyridis preferred odours from healthy wheat plants mixed with aphid-infested pea plants. As for E. balteatus, their searching and oviposition behaviours were stimulated by the different wheat/pea combinations associated with aphid infestations. A field trial was also carried to compare the effect of mix and strip cropping wheat with pea on aphids and their natural enemies with both monocultures. Wheat and pea aphid populations were significantly reduced by both types of intercropping when compared to monocultures. Moreover, higher abundances of hoverflies, lacewings and ladybirds were found in wheat mixed with pea field, followed by strip cropping and monocultures. These findings show that wheat-pea intercropping can be efficient to reduce aphid populations, namely by promoting their biological control.
Insecticidal activities of diketopiperazines of Nomuraea rileyi entomopathoge...IJEAB
Entomopathogenic fungi are fungal organisms extensively used in various parts of the world as biopesticides against insect pests that cause important economic damage. Various secondary metabolites produced by these fungi have many potential biological activities. The present study was undertaken to evaluate the insecticidal activity of extracts and pure compounds from Nomuraea rileyi (Farlow) Samson entomopathogenic fungi against Spodoptera frugiperda Smith (Lepidoptera), Ceratitis capitata Wiedemann (Diptera) and Tribolium castaneum Herbst (Coleoptera), three insect pests that generate serious economic losses in the northwest of Argentina. Diketopiperazines were extracted from the culture free supernatant of the media with ethyl acetate. Antifeedant properties were detected in all extracts under dietary choice conditions (300 ug/ g of diet). The maximum antifeedant activity was noted in cycles (Pro-Val) (86.02) and cycle (Pro-Phe) (73.47), while the rest of the extracts and metabolites exhibited varying degrees of moderate or less toxic effects. The maximum oviposition deterrence against C. capitata (55.86%) was recorded with cycle (Pro-Phe) at a 50 µm/cm2 dose. Culture medium extracts supplemented with insect remains and all pure compounds showed repellent action against T. castaneum. The main repellency was observed in phenylacetic acid and cycle (Pro-Val) with RI values of 42 and 41% respectively. The present study would suggest the possible utilization of entomopathogenic fungal metabolites as an effective agent for controlling insect pests that cause important economic losses.
Analyses of Bacterial Community Dynamics Present in Culex quinquefasciatus Co...BRNSS Publication Hub
Culex quinquefasciatus are among the most important vectors of arboviral diseases worldwide. Recent
studies indicate that diverse midgut microbiota of mosquitoes significantly affects development, digestion,
metabolism, and immunity of their hosts. Here, we studied the bacterial diversity found in midgut part
of C. quinquefasciatus to understand the host and microbe interaction. The adult C. quinquefasciatus
mosquitos were collected from Loyola College Campus, Chennai, using ovitraps, and midgut part was
extracted; moreover, the DNA templates were isolated and amplified by polymerase chain reaction. The
DNA amplicons were sequenced by Illumina MiSeq gene sequencer. The total of 279,157 reads was
classified into 85, the bacterial genera of Pseudomonas, Klebsiella, Staphylococcus, and Aeromonas
predominantly found to be high when compared to the other bacterial genera. The present data strongly
encourage further investigations to verify the potential role of the detected bacteria in mosquito for the
transmission of several vectoral diseases.
2 ijreh mar-2018-1-evaluation of some insecticidesAI Publications
The present study was planned to test on certain chemical insecticides from different groups such as organophosphates, pyrethroids and Bioinsecticide. Among these compounds two were chemical insecticides (Propetamphos and Cypermethrin), while the third one is Bioinsecticide (Baciloid 5000: Bacillus thuringiensis) against Culex pipiens, the dominant mosquito species in Abha city. Taking LC50 values (concentration which to kill 50% of mosquito larvae) into consideration, mosquito larvae of CX. Pipes against Propetamphos was effective (LC50 0.0162 ppm) against the 3rd instar of the laboratory strain comparing with a field strain which was 0.0442 ppm. At LC90 level, data indicated that Propetamphos (LC90 0.8109 ppm) was effective insecticide against the 3rd instar larvae of laboratory strain, while against field strain gave (LC90 3.31 ppm). Similarly, the results clearly showed that Cypermethrin was also very effective insecticide (LC50 0.0132 ppm) against the adult females against laboratory strain, while against field strain Cypermethrin gave (LC50 0.1192 ppm). On the other hand, the residual activity of Bacillus thuringiensis var. israelensis reached from 4 to 20 days of concentrations ranged between 0.001 to 100 p.m. in case laboratory strain, while reaching between 6-23 days of concentrations ranged between 0.001 to 100 p.m. in case field strain. Mortality percent was also found between 11.7 to 96.8% of concentrations ranged between 0.001 to 100 p.m. against laboratory strain in the 1st week, whereas ranged between 0.0 to 70.8% in the 2nd week against the same concentrations finally ranged between 0.0 to 12.7% in the 3rd week. Hence, the field collected larvae of Culex pipens were more susceptible and have prolonged residual effect as compared to laboratory reared.
Microbiological Investigations of Selected Flies of Public Health Importance ...iosrjce
Bacteria associated with flies of public health importance in Nigeria are not well known and their
ecology is also not well understood. We aim to determine the bacteria associated with flies of waste dump site.
Three flies of public health significance were collected from a waste dump site of the Rivers State University of
Science and Technology, Port Harcourt. The three dipterous flies were Luciliasericata, Chrysomyasp and
Musca domestica..The three flies were all of medical importance.The microbial load on three species of flies
was investigated using standard plate count methods. The fly samples were collected from the Post Graduate
Entomology Laboratory was cultured to isolate and identify the microbes associated with them. The samples
were analyzed for total heterotrophic bacteria and fungi counts. The study revealed high heterotrophic bacteria
and fungi counts in all three species of the flies used, with Musca domestica having the highest count of 2.9 X
109Cfu/gram and Chrysomyasp with the least count of 3.4 x 10 5Cfu/g and fungi counts ranged from 3.1 X
103Cfu/g to 2.9 X 105Cfu/g. The bacteria isolated from these samples includes: Escherichia coli,
Pseudomonassp,, Bacillussp, Enterobactersp, Staphylococcussp,Salmonellasp, Proteussp, and Klebsiellasp,
while the fungi species isolated includes: Penicilliumsp,
Aspergillussp,Rhizopussp,Cladosporiumsp,Aspergillusflavus, Aspergillusniger, Fusariumsp and Trichoderma
sp.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
1. KHAWAJA TAIMOOR SHAHID
SUPERIOR COLLEGE M.B.DiN
Significance ofbiologicalcontrol in agriculture
Introduction Michael Grodowitz – Research Entomologist The Biological Control of
Pests Research Unit (BCPRU); whose main mission is the development of biological and
biorational (i.e., having a minimal disruptive influence upon the environment and its
inhabitants) components for sustainable and environmentally compatible pest
management; is comprised of 10 scientists and 16 support personnel. The unit is housed
within the USDA-ARS National Biological Control Laboratory (NBCL) located at the
Jamie Whitten Delta States Research Center (JWDSRC) in Stoneville, Mississippi. The
NBCL was officially formed in 2002. This laboratory is the first facility in the world to
have both the infrastructure and the scientific specialisations needed to fully investigate
integrated research on the use of biocontrol technologies. The BCPRU researchers
develop practical methods of mass propagation, storage, delivery of beneficial organisms,
targeted release strategies for integrated pest management, and application of classical
biocontrol for the management of invasive insects and weeds. Current research activities
include mass-rearing of economically important insect species, molecular biology of both
insects and plant pathogens, fermentation, invasive ant management, and biocontrol of
invasive weeds. In 2015, the BCPRU produced 17 publications; 1 patent; developed or
modified artificial diets for three species; identified potential biorational compounds for
invasive ant control; completed host-specificity studies on egg parasitoids of the kudzu
and bagrada bugs; demonstrated cost effective strategies to reduce aflatoxin
contamination; and furthered the use of pathogens for invasive plant management.
Following are some prime examples of current and ongoing research activities at the
BCPRU:
Production of Predatory Mites as Biocontrol Agents
Most predatory mites belong to the family Phytoseiidae and are highly effective predators
used mainly to control the two-spotted spider mite (Tetranychus urticae) in many
different crops. However, phytoseiid mites have been shown to provide effective control
of other mite pests as well as some insects including thrips and white flies (Bolckmans
2007). It is estimated that at least 20 species of phytoseiid mites are produced
commercially and sold around the world for biological control of mite pests in different
cultivars (Zhang 2003). Among the most important predatory mites produced
commercially include Phytoseiulus persimilis (Figure 1), Amblyseius swirskii,
Neoseiulus californicus, N. cucumeris, N. fallacis, Iphiseius degenerans , Galendromus
helveolus, G. occidentalis, and Mesoseiulus longipes (Zhang 2003, Leppla 2014).
2. Production methods range from open systems in greenhouses to fully enclosed using
climate controlled rooms (Bolckmans 2007). Some predatory mites can be reared on
alternative prey eliminating the need to culture plants for spider mite production. Others,
like I. degenerans, can be reared solely on pollen. However some of the most important
phytoseiid predators, like P. persimilis, must be produced on their natural prey (spider
mites). This requires the use of multiple isolated greenhouses to culture bean plants,
infest them with spider mites and then use them to feed the predators. A pure culture of
spider mites (free of predators) must be maintained for inoculating the main production
greenhouse, where predators are later introduced (Gilkeson 1992). A section of the bench
is harvested when it has reached the maximum predator density. Introduction of P.
persimilis into the infested plants requires perfect timing to allow maximum spider mite
reproduction without losing the plants to the mite infestation. Predator harvesting often
exposes the predators to stressful conditions of starvation and many are lost to inefficient
collection methods. Enclosed rearing systems offer the potential of greater control of
environmental conditions and better containment preventing excessive losses. Several
enclosed methods have been proposed to rear P. persimilis by introducing its natural prey
into different types of enclosure (Theaker and Tonks 1977, Fournier 1985, Overmeer
1985, McMurtry et al. 1989, Shih 2001, Morales-Ramos and Rojas 2014). But,
modifications to scale up those systems in order to achieve the required level of predator
production have proven difficult. One promising example of an enclosed and continuous
rearing system for phytoseiid mites has been developed in the National Biological
Control Laboratory. This method relays on bean plants grown using trays and infested by
spider mites. Plants are later cut from the soil base to release the trays, which are
introduced into large cages where predatory mites are later introduced (Morales-Ramos et
al. 2012) (Figure 2). Trays with freshly infested plants are introduced through a door to
the upper part of the cage and after being exposed to the predatory mites for a week, they
are removed from the bottom of the cage using a lower door. Trays are moved down
using a simple patented mechanism. Gravid predatory mite females tend to remain close
to the prey, while young adult predatory mites tend to move and migrate to the upper
parts of the cage. Mites accumulate in a collection cup located at the top of the cage from
where mites are collected daily. A small prototype occupying approximately ½ m2 of
space was capable of a continuous production of up to 14,000 predators per week.
Dimensions of the cage may be increased to achieve higher production levels and using
hydroponic methods may simplify procedures to place the infested bean plants in the
trays. This enclosed system holds promise for the future of predatory mite production.
Importance of Ladybird Beetles as Biocontrol Agents in Greenhouses and High Tunnels
Ladybird beetles (a.k.a., lady beetles, or ladybugs) are well-documented as important
biological control agents (predators) of plant pests in urban and agricultural landscapes
throughout the world (Dixon 2000, Hodek et al. 2012). Ladybird are less well-known for
3. their role as predators of pests in semi-enclosed systems, such as in greenhouses,
plantscapes, or high tunnels (Yang et al. 2014). One of the research projects conducted
involves the assessment of ladybird beetles as predators of aphids in high tunnels in the
southern USA. Aphids are pests with a long history of infesting crop plants in
greenhouses and other protective structures (Blümel 2004). The capacity of ladybirds to
suppress aphid populations in greenhouses and high tunnels is equivocal. Successful
suppression apparently depends on a number of biotic factors including host plant
defenses (trichomes), predator/prey densities, and intraguild interactions of ladybirds
with other biocontrol agents (predators and parasitoids) that could increase or even
decrease suppression by ladybird beetles. At the National Biological Control Laboratory,
scientists are developing techniques to mass-produce ladybird beetles, e.g., the pink
spotted lady beetle, Coleomegilla maculata (Figure 3) for release into high tunnels to
suppress aphid populations on plants, such as strawberry. Some of the research conducted
has centered on the development of cost-effective diets to use as alternative food for C.
maculata. Also, preliminary releases of C. maculata immature and adult stages on
strawberry plants, infested with aphids, suggest that this particular species could serve as
a great ally in biocontrol of aphids in greenhouses and high tunnels in the U.S. However,
more research is necessary to determine predation efficiency. More information is needed
on survival rates of immature and adult stages, post release, and on the interaction of
released ladybirds with predators (from the neighboring landscape), which find their way
into high tunnels each growing season. Of particular concern is preventing aphid-tending
ants from entering high tunnels and interfering with the predation potential of ladybirds.
Biological Control of the Imported Fire Ant
The red imported fire ant, Solenopsis invicta, is one of the most successful invasive ants
in the world, and is regarded as one of world’s worst invasive exotic species. Native to
South America, S. invicta has been introduced into many countries and regions, including
the United States, Australia, China, the Philippines, Thailand, Taiwan, Hong Kong,
Macau, etc. (Ascunce et al., 2011). A tremendous effort has been made over the past few
decades to mitigate fire ant problems using biological control agents. These agents
include parasitoids, such as phorid flies, fungi, bacteria, microsporidia, viruses, and
nematodes. Beauveria bassiana, an EPA-approved insect biological control agent, has
also been investigated for fire ant control. Unfortunately, although it has shown great
promise in the laboratory, it has been less successful under field conditions. Environment
conditions in an ant nest are constantly being regulated by the ant workers for the
survival and development of the colony and this is believed to make them amenable for
the growth of microbial pathogens (Hölldobler and Wilson 1990). Furthermore, high
genetic relatedness among individuals in a colony may also make social insects prone to
diseases (Tarpy 2003). Therefore, for ants to thrive, they must depend on their successful
evolution of effective defense strategies against diseases. A range of defense strategies
4. have been evolved for combating infectious diseases in social insects (Schlüns and
Crozier 2009). Defenses against pathogens at group level in social insects have been
described as “social immunity” (Cremer et al. 2007; Cotter and Kilner 2010).
Antimicrobial agents are a crucial component in social immunity. Volatility of
antimicrobial agents may have tremendous effect on their efficacy against pathogens in
an ant colony. Nonvolatile compounds may work more passively since direct contact by
pathogens is required, whereas volatile compounds can function more actively because
they can effectively reach the targets by fumigating the whole nest. Researchers at the
National Biological Control Laboratory demonstrated the antimicrobial property of nest
volatiles produced by red imported fire ants against B. bassiana. The germination rate of
B. bassiana spores were significantly reduced after they were exposed to nest volatiles
within an artificial ant nest. This was determined by simulating in an artificial fire ant
nest the levels and fluctuations of O2 and CO2 as those detected in fire ant nests. The
germination rate of B. bassiana was not suppressed in the artificial nest due to the
changes of O2 and CO2; but the toxicity of nest volatiles. Nest fumigation may be an
important component of the social immune system in S. invicta. This information is
important not only in understanding social immunity in fire ants, but also in developing
biological control strategies using pathogenic microorganisms, since any successful
biological control agents must be able to overcome the toxicity of fire ant nest volatiles.
Trichoderma as a Biological Control Agent of Insect Pests
Trichoderma spp., a cosmopolitan, filamentous fungi that is commonly isolated from soil,
have been shown to enhance nutrient uptake, stabilise soil nutrients, promote root
development and increase root hair formation (Harman, 2006) in plants. These attributes
identify Trichoderma spp. as a promising biological control agent ideal for further
research and product development for the control of insect pests. The drying of
Trichoderma spp. on a large scale is a major constraint due to the loss of conidia viability
at elevated temperatures, and can hinder the development of new products. Research
conducted at the National Biological Control Laboratory has shown that the
microencapsulation of the aerial conidia of Trichoderma harzianum through spray drying
at elevated temperatures offers several advantages for formulation development and
downstream processing of this organism (Jin, Custis, Biological Control 2011).
Microencapsulation is generally defined as a process that encases one substance within
another on a small scale. This process will normally produce encased materials ranging
from less than one micron to several hundred microns in size. It is preferred that
formulations of Trichoderma exhibit a level of 5 x 109 cfu/g to be useful in a variety of
applications (Harman and Custis, 2006). In order to achieve this density level the finished
dried Trichoderma conidia must be greater than 90% pure conidia and be in the form of a
flowable powder. Utilising different sugars as our microencapsulating agent we were able
to develop a method for spray drying the conidia of Trichoderma harzianum. A two phase
5. solid production system was used to produce the conidia needed for our research,
utilising the liquid phase to produce our initial inoculums for the solid phase. Following
liquid phase production in shake flasks solid media consisting of 50% Rice Chaff and
50% Extra Long Grain Enriched Rice was inoculated and incubated in growth rooms at
280C for 10 days. Resulting conidia were washed from the solid media with DI water and
poured through a 100 mesh screen. This conidial suspension was centrifuged to produce a
paste which was then used for the subsequent microencapsulation and spray drying
experiments. Varying levels of sucrose, molasses and glycerol solutions were analysed
for their efficacy as microencapsulating agents, along with varying spray drying
temperatures. Results indicated that Trichoderma conidia encapsulated with sugar
solutions ranging from 0.5% to 8% resulted in higher survival rates (cfu/g) than the non-
microencapsulated controls. Temperature studies indicated that optimum inlet drying
temperatures are between 500C and 800C respectively. Our results demonstrated a spray
drying process that could produce a flowable (particle size around 10-25µm) technical
powder containing over 99% conidia ideal for use in formulation development.
KHAWAJA TAIMOOR SHAHID
SUPERIOR COLLEGE
M.B.DiN