Contents
Identification of major parasitoids and predators commonly being used in biological control
Insect Orders Bearing Predators and Parasitoids Used in Pest Control
Mass Multiplication Techniques for Predators and Parasitoids in Biological Control
Identification of major parasitoids and predators commonly being used in biological control
Major Parasitoids:
Biological control involves the use of natural enemies, such as parasitoids, predators, and pathogens, to manage pest populations in agricultural and ecological systems. Parasitoids are insects that lay their eggs on or in other insects, eventually killing the host. Here's an overview of some major parasitoids commonly used in biological control, along with their identification characteristics:
- Trichogramma spp.:
- Identification: Trichogramma is a group of tiny wasps with a size range of 0.2-1.5 mm. They are often metallic-colored and have delicate wings.
- Characteristics: Female Trichogramma lay their eggs inside the eggs of pest insects, such as moth eggs. The emerging Trichogramma larvae feed on the host eggs.
- Use in Biological Control: Trichogramma is widely used to control lepidopteran pests like moth species that lay eggs on crop plants.
- Aphidius spp.:
- Identification: Aphidius are small parasitoid wasps with a size of around 2-3 mm. They have a slender body and antennae.
- Characteristics: Female Aphidius lay their eggs inside aphids, and the developing larvae consume the host from the inside.
- Use in Biological Control: Aphidius is used to control aphid populations in various crops.
- Encarsia formosa:
- Identification: Encarsia formosa is a tiny parasitoid wasp, around 1 mm in size. They have a distinctive black body and transparent wings.
- Characteristics: Female Encarsia formosa parasitize whitefly nymphs by laying their eggs inside them.
- Use in Biological Control: Encarsia formosa is used to control whitefly populations, which are notorious for damaging crops.
- Trichoderma spp.:
- Identification: Trichoderma is a group of fungi with white to greenish growth on the substrate. They produce conidia in conidiophores.
- Characteristics: Trichoderma species are used as mycoparasites to control fungal diseases by attacking the pathogenic fungi.
- Use in Biological Control: Trichoderma is used as a biological control agent against various soil-borne plant pathogens.
- Parasitic Nematodes (Steinernema spp. and Heterorhabditis spp.):
- Identification: Parasitic nematodes are microscopic roundworms that attack insects and other pests in the soil.
- Characteristics: The parasitic nematodes enter the pest's body and release bacteria that kill the host. The nematodes then feed on the bacteria and host tissue.
- Use in Biological Control: These nematodes are used against soil-dwelling pests, such as grubs, caterpillars, and beetles.
- Dacnusa sibirica:
- Identification: Dacnusa sibirica is a parasitoid wasp with a size of about 3-4 mm. It has a black body with white stripes.
- Characteristics: Female Dacnusa sibirica lay their eggs on leaf-mining pest larvae, and the emerging larvae consume the host.
- Use in Biological Control: Dacnusa sibirica is used to control leaf-mining pest populations.
- Chrysoperla spp. (Green Lacewings):
- Identification: Chrysoperla adults have a delicate appearance with large, transparent wings and golden eyes.
- Characteristics: Green lacewing larvae are voracious predators, feeding on various soft-bodied insects, including aphids and mites.
- Use in Biological Control: Green lacewings are employed for controlling aphids, thrips, and other small insects.
- Cotesia spp.:
- Identification: Cotesia are small parasitoid wasps with a size of around 3-5 mm. They often have distinctive markings on their abdomen.
- Characteristics: Female Cotesia lay eggs in caterpillar hosts. The developing larvae feed on the host's body and eventually kill it.
- Use in Biological Control: Cotesia is used against caterpillar pests, such as cabbage worms and armyworms.
- Bracoviruses:
- Identification: Bracoviruses are not visually identifiable. They are endoparasitic viruses carried by some parasitoid wasps.
- Characteristics: Some parasitoid wasps inject bracovirus particles into their host along with their eggs. The virus affects the host's immune system, allowing the parasitoid to develop.
- Use in Biological Control: Bracoviruses are used indirectly by parasitoid wasps as part of their biological control strategy against host insects.
Major Predators:
Predators play a crucial role in biological control by consuming pest insects and helping to regulate their populations. Here are some major predators commonly used in biological control, along with their identification characteristics:
- Ladybird Beetles (Coccinellidae):
- Identification: Ladybirds are small beetles with round or oval bodies. They are often brightly colored with spots.
- Characteristics: Ladybirds are voracious predators of aphids, mealybugs, and other soft-bodied insects.
- Use in Biological Control: Ladybirds are released to control aphid and other pest populations in various crops.
- Predatory Mites (Phytoseiidae):
- Identification: Predatory mites are tiny arachnids with elongated bodies. They move quickly on plant surfaces.
- Characteristics: Predatory mites feed on small pests like spider mites and thrips.
- Use in Biological Control: Predatory mites are used in greenhouses and fields to manage spider mite and thrips populations.
- Hoverflies (Syrphidae):
- Identification: Hoverflies resemble small bees or wasps but have larger eyes and different wing venation.
- Characteristics: Hoverfly larvae are aphid predators, consuming large numbers of aphids.
- Use in Biological Control: Hoverflies are employed to control aphid infestations in crops.
- Predatory Bugs (Anthocoridae and Miridae):
- Identification: Predatory bugs have a distinct elongated body shape and strong piercing-sucking mouthparts.
- Characteristics: Predatory bugs feed on various soft-bodied insects, including aphids, thrips, and mites.
- Use in Biological Control: Predatory bugs are used to manage aphid and other pest populations.
- Parasitic Wasps (Parasitica):
- Identification: Parasitic wasps come in various sizes, shapes, and colors. They are often smaller than pest species.
- Characteristics: Parasitic wasps lay eggs inside pest insects. The developing larvae consume the host from the inside.
- Use in Biological Control: Different species of parasitic wasps target a wide range of pests, including caterpillars, aphids, and more.
- Predatory Beetles (Carabidae and Staphylinidae):
- Identification: Predatory beetles have elongated bodies and strong mandibles.
- Characteristics: Many ground beetles and rove beetles are predators of soil-dwelling pests, insect eggs, and larvae.
- Use in Biological Control: These beetles contribute to pest control in agricultural fields.
- Spiders (Arachnida):
- Identification: Spiders have two body parts, eight legs, and produce silk.
- Characteristics: Many spiders are generalist predators, feeding on a variety of insects and pests.
- Use in Biological Control: Spiders contribute to natural pest control in various ecosystems.
- Assassin Bugs (Reduviidae):
- Identification: Assassin bugs have a distinct "neck" and elongated body. Some have a camouflage appearance.
- Characteristics: Assassin bugs are predators of various insects, using their piercing-sucking mouthparts to feed on prey.
- Use in Biological Control: Assassin bugs help manage pest populations, including caterpillars and other insects.
- Praying Mantids (Mantidae):
- Identification: Praying mantids have a distinctive elongated body and forelegs adapted for grasping prey.
- Characteristics: Mantids are ambush predators, waiting for insects to approach before capturing them.
- Use in Biological Control: Mantids consume a variety of insects and contribute to natural pest control.
- Lacewings (Chrysopidae):
- Identification: Adult lacewings have large, transparent wings and golden eyes.
- Characteristics: Lacewing larvae are voracious predators, feeding on aphids, mites, and other small insects.
- Use in Biological Control: Lacewings are released in fields and greenhouses to manage aphid and other pest populations.
Utilizing these beneficial predators in biological control programs helps reduce the reliance on chemical pesticides and promotes sustainable pest management practices.
Insect Orders Bearing Predators and Parasitoids Used in Pest Control
Predators and parasitoids are important natural enemies of pest insects, and they are widely used in biological pest control programs to manage pest populations. These beneficial insects belong to various insect orders. Here are some of the key insect orders bearing predators and parasitoids commonly used in pest control:
- Coleoptera (Beetles):
- Many beetle species are predators of pest insects. Ground beetles (Carabidae) and rove beetles (Staphylinidae) are examples of beneficial beetles used in pest control.
- Ground beetles are generalist predators, consuming a wide range of insect pests in agricultural fields.
- Rove beetles are predators of soil-dwelling pests, insect eggs, and larvae.
- Hymenoptera (Wasps, Bees, and Ants):
- Hymenopteran insects include parasitoid wasps that lay eggs inside or on pest insects. These eggs hatch into larvae that consume the host from within.
- Parasitoid wasps belong to the families Braconidae, Ichneumonidae, and Chalcididae. They target a variety of pests, including caterpillars, aphids, and more.
- Some ants are also predators and contribute to natural pest control by consuming pest insects.
- Diptera (Flies):
- Certain fly species are predators of pest insects. For example, predatory syrphid flies (Syrphidae) are often used to control aphid populations.
- Tachinid flies (Tachinidae) are parasitoids that lay eggs on or in pest insects. The larvae consume the host from within.
- Neuroptera (Lacewings and Antlions):
- Lacewings (Chrysopidae) are known for their voracious larvae that feed on aphids, mites, and other small insects.
- Antlions (Myrmeleontidae) are larvae that create pit traps in sandy soil to capture and consume small insects.
- Odonata (Dragonflies and Damselflies):
- Adult dragonflies and damselflies are predators of flying insects. They are not commonly used in pest control but contribute to overall insect population regulation.
- Orthoptera (Crickets, Grasshoppers, and Katydids):
- Some predatory crickets and katydids are used to control pest insects. However, their use in pest control is limited compared to other orders.
- Arachnida (Spiders):
- Spiders are not insects but belong to the arachnid class. They are important predators of insects and play a role in natural pest control.
- Hemiptera (Assassin Bugs):
- Certain assassin bugs (Reduviidae) are predators that use their piercing-sucking mouthparts to feed on a variety of insect pests.
- Dermaptera (Earwigs):
- Some earwigs are predators of small insects and help control pest populations in gardens and agricultural fields.
- Mantodea (Praying Mantids):
- Praying mantids are predators that use their forelegs to capture and consume a variety of insects.
Utilizing these insect orders in biological pest control programs helps maintain ecological balance and reduce the reliance on chemical pesticides. By releasing and conserving these natural enemies, farmers can achieve sustainable and environmentally friendly pest management.
Their Mass Multiplication Techniques
To effectively use predators and parasitoids in biological pest control programs, it's crucial to mass multiply these beneficial insects. Mass multiplication ensures a sufficient number of predators and parasitoids for release in the field. Here are some common techniques for mass multiplication:
- Predatory Beetles (Coleoptera):
- Ground beetles and rove beetles can be mass multiplied by providing suitable habitat and food sources. They can be reared in containers with appropriate substrate and prey insects.
- Parasitoid Wasps (Hymenoptera):
- Parasitoid wasps are often reared on factitious hosts or alternative hosts in the laboratory. This involves providing host insects for the parasitoids to lay eggs on or in.
- Factitious hosts are easy-to-rear insect species that serve as a substitute for the natural host. For example, eggs of the Mediterranean flour moth (Ephestia kuehniella) are commonly used as factitious hosts for parasitoid wasps.
- Predatory Flies (Diptera):
- Syrphid flies and tachinid flies can be mass reared using artificial diets and suitable rearing containers.
- The larvae of syrphid flies can be reared on diets containing pollen, sugar, and other nutrients.
- Tachinid flies require host insects for oviposition, and their larvae develop within the host.
- Lacewings (Neuroptera):
- Lacewings can be mass reared in controlled environments using artificial diets or prey insects.
- Eggs of lacewings are laid on cards or substrates, and the emerging larvae can be collected for release.
- Dragonflies and Damselflies (Odonata):
- Mass rearing of dragonflies and damselflies is challenging and not commonly practiced for biological control.
- Assassin Bugs (Hemiptera):
- Assassin bugs can be mass multiplied by providing suitable prey insects and maintaining conducive rearing conditions.
- Praying Mantids (Mantodea):
- Praying mantids can be mass reared by providing them with a continuous supply of suitable prey insects.
- Other Techniques:
- In some cases, insectaries are established where natural enemies are reared on a large scale. These insectaries utilize controlled conditions to optimize reproduction and development.
Key considerations for mass multiplication include providing appropriate nutrition, rearing containers, temperature, humidity, and photoperiod conditions. Quality control measures are essential to ensure that the released beneficial insects are healthy and effective in controlling target pests.
Mass multiplication techniques vary depending on the specific insect species, their biology, and the target pest. Researchers and practitioners in the field of biological control continuously work to improve and develop effective mass multiplication methods for various predators and parasitoids.
Note: Summarized key points for easy exam review.
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