Biological Control Programs Study Notes

Predator: An insect or arthropod, like spiders, that consumes another insect (its prey).
Parasitoid: An insect that develops on or within another insect (the host), leading ultimately to the host's death.
Parasite: An insect that lives on another insect or animal without killing it.
Pathogens: Microorganisms including bacteria and nematodes that are lethal to insects.
Beneficials: Encompasses all of the above except for parasites; these organisms assist in pest control.

Three Primary Categories:
1. Classical Biological Control: This involves introducing a predator, parasitoid, or pathogen from another nation to manage an invasive or introduced pest.
2. Augmentation Biological Control: This entails releasing more beneficial organisms to mitigate the pest population.
3. Conservation Biological Control: The focus here is on adjusting programs to promote ecosystem balance, such as employing selective treatments or providing alternative food sources.

Definition & Role: Microscopic organisms that infect insects, proliferate within them, and result in the pest's death.
Types of Pathogens Used in Biological Control: Bacteria, viruses, fungi, protozoans, and nematodes.

Bacillus thuringiensis (Bt): A soil bacteria with insecticidal properties; it has numerous strains that target specific pests:
- Bt kurstaki: Targets Lepidoptera larvae, commonly sold under trade names like Dipel, Javelin, and Thuricide.
- Bt tenebrionis: Effective against leaf beetles, sold as Novodor.
- Bt galleriae: Specifically targets beetles and white grub control.

Evaluation Data (Lancaster, Ohio, 2011): A chart presenting the percentage of control of white grub populations using various formulations of GrubGONE, showing different application rates on specific dates with corresponding control efficacy.
Trade names for competitive products, such as GrubEx and Meridian, illustrate comparative effectiveness in controlling larval pests.

GrubGONE: A biological insecticide targeting various turf and ornamental pests, including leaf-eating insects.
- Active Ingredient: Consists mainly of Bacillus thuringiensis galleriae.
- Note: GrubGONE demonstrated effective pest control without adversely impacting beneficial insects.

The mode of action of Bt involves the production of protein toxins known as delta-endotoxins, which impact the insect gut:
- These endotoxins bind to the gut lining of insects and compromise the gut, leading to cessation of feeding and eventual death.
- Younger larval hosts are more susceptible than older larvae, necessitating ingestion for effectiveness.

Case Study: Gypsy Moth suppression project aimed at preventing host tree defoliation via targeted applications of biological agents.
- Project Objectives: Maintain defoliation below 30% and reduce insect populations to below threshold levels for subsequent years.

Description: Unsegmented roundworms that serve as parasites to insects, often acting in conjunction with specific bacteria (e.g., Xenorhabdus).
Life Cycle: EPNs go through an adult, four juvenile stages, and an egg phase; the third stage juveniles are the infectious form.

Various strains of entomopathogenic nematodes target specific pests; for example:
- Steinernema carpocapsae: Effective for borers, weevil larvae, etc.
- Heterorhabditis spp.: Noted for efficacy against pests like white grubs.
Application Rates: Often recommended at 1 billion units per acre for effective pest control.

Efficacy is influenced by environmental factors:
1. Desiccation: Soil must remain moist during and after application.
2. Sunlight Exposure: Increased mortality rates due to UV degradation.
3. Temperature Extremes: Ideal conditions range between 50-85°F.

Fungi can naturally occur in soils and are used globally in agricultural pest management.
- Efficacy relies on environmental conditions during application; high humidity and temperatures are vital for effectiveness.

Beauveria bassiana and Metarhizium spp.: Established fungal pathogens; application can lead to significant pest mortality by overwhelming insect cuticles, causing desiccation.
- Examples include using Beauveria for controlling billbug infestations and utilizing Metarhizium for managing white grub populations.

Defined as insect-specific viruses that often face challenges due to high production costs and host specificity:
- Examples of forest pest control using viruses are Gypcheck® for Gypsy Moths and TM BioControl-1® for Douglas-fir tussock moth.

The biological control landscape includes a diverse array of strategies and applications, focusing primarily on integrated pest management using a variety of organisms (microorganisms, pathogens) to suppress pest populations effectively.