Biocontrols in Organic Farming in Hawaii

Eric Collier
15 hours ago
6 min read

Introduction to Beneficial Insects

As an organic farmer, one of the biggest challenges you may face is managing pests without the use of harmful chemicals. However, did you know that nature has its own built-in pest management system? Beneficial insects play a crucial role in keeping pest populations under control and promoting overall plant health.

Farming organically in our island climate brings unique challenges, especially when managing tropical pests year-round. For decades, the standard agricultural approach relied heavily on chemical sprays to wipe out problematic insects. However, modern organic agriculture requires a fundamental shift in how we view our fields. We are transitioning from a mindset of total "pest eradication" to one of "ecological equilibrium."

Instead of trying to eliminate every single pest, the goal is to balance the ecosystem so that natural predators keep pest populations at low, manageable levels. This approach protects your crop yields without harming the surrounding environment. Think of biological control as partnering with nature rather than fighting against it. By understanding how to manage these biological relationships, you can protect your crops, improve your soil, and maintain a thriving, sustainable farm.

Hawaii's Biocontrol History

Hawai‘i has been experimenting with classical biological control for over a century, providing plenty of evidence-based lessons for today's growers. The practice started informally—and sometimes disastrously—by private citizens. In 1883, plantation owners introduced the mongoose from Jamaica to control rising rat populations in sugarcane fields. The result was a classic failure. Mongooses are active during the day, while rats are nocturnal. Instead of eating rats, the mongoose devastated populations of ground-nesting native birds.

Fortunately, government-sanctioned programs eventually brought scientific rigor to the process. In 1890, the successful introduction of the vedalia beetle completely controlled the destructive cottonycushion scale on citrus plants. More recently, the native wiliwili tree was saved from the invasive Erythrina gall wasp by the careful introduction of a specific parasitic wasp from Africa. Today, biocontrol agents undergo rigorous testing to ensure they only target specific pests, giving organic farmers a safe, reliable tool for their operations.

The Three Pillars of Biological Pest Control

Biological control is generally broken down into three distinct strategies. Understanding these pillars will help you choose the right technical assistance for your specific farming operation.

Importation (Classical Biocontrol)

Think of importation as calling in specialized reinforcements from overseas. This method is primarily used when an invasive pest accidentally arrives in Hawaii without its natural predators. Scientists identify a highly specific natural enemy from the pest's native habitat, test it rigorously to ensure it will not harm native species, and release it to establish a permanent population. The successful control of the Erythrina gall wasp is a perfect example of classical biocontrol at work.

Augmentation Biocontrol

Are you struggling with a sudden outbreak of aphids in your greenhouse? Augmentation might be your answer. This strategy involves the periodic release of natural enemies to give nature a temporary boost. Unlike importation, you are not trying to establish a permanent population. Instead, you are using beneficial insects—like ladybeetles or predatory mites—as a short-term intervention to quickly reduce pest numbers during peak seasons.

Conservation Biocontrol

Conservation biocontrol is about building a welcoming home for the beneficial insects already living on your farm. This method involves creating conditions that encourage the survival and reproduction of native predators and parasitoids. You can implement this by:

Planting cover crops that provide shelter for predatory ground beetles.
Maintaining floral resources along field edges to supply nectar for parasitic wasps.
Avoiding broad-spectrum organic pesticides that might accidentally harm beneficial insect populations.

Examples of Broad-Spectrum Organic Pesticides

Broad-spectrum organic pesticides can be effective in controlling a wide range of pests, but they may also impact beneficial insect populations if not used carefully. Some examples include:

Neem Oil: A natural insecticide derived from the seeds of the neem tree, neem oil disrupts hormonal systems in pests, making it difficult for them to grow or reproduce. However, it can also affect insects like bees if applied during active foraging periods.
Pyrethrin: Extracted from chrysanthemum flowers, pyrethrin is highly effective against a variety of insects, including aphids and beetles. Despite being organic, its broad-spectrum nature can harm non-target pollinators if sprayed indiscriminately.
Spinosad: A product of naturally occurring soil bacteria, spinosad works well against thrips, fruit flies, and caterpillars. It should be applied selectively to minimize harm to beneficial insects like predatory beetles and parasitic wasps.

Using these pesticides responsibly—by targeting applications and adhering to recommended best practices—ensures they complement, rather than compromise, an integrated pest management strategy.

Creating a Welcoming Environment for Benef

Aligning with Organic Standards (NOP)

For growers pursuing or maintaining organic certification, biological control is more than just a good idea—it is an essential component of the USDA National Organic Program (NOP) standards. Section 205.206 of the NOP regulations requires producers to use preventative management practices for crop pests, weeds, and diseases.

Before you can apply any approved botanical or biological substance, you must first demonstrate that you have attempted other preventative measures. Biocontrol perfectly aligns with these integrated pest management (IPM) requirements. By focusing on conservation and augmentation methods, you begin to build a resilient farming operation that naturally suppresses pests, keeping their population below the economic threshold. This proactive approach not only satisfies regulatory guidelines but also lowers your long-term input costs and protects the health of your soil.

Agents of Biological Control

1. Parasites and Parasitoids

Parasite – an organism that lives in or on the body of another organism (the host) during some portion of its life cycle.

Parasitoid – an arthropod that parasitizes and kills another arthropod (insects, mites, spiders, and other close relatives) host; a parasitoid is parasitic in its immature stages and free living as an adult.

Parasitoids have been used in biological control more than any other type of agent. The major types of insects that are parasitoids: wasps, flies, some beetles, mantisflies, and twisted-winged parasites.

Adult female parasitoids lay their eggs inside the host (the host arthropod is usually in its immature stage) by penetrating the body wall with their ovipositor or they attach their eggs to the outside of the host’s body.

2. Predators

Predator – “Free-living animal that feeds on other animals; it may attack prey in both its immature and adult stages; usually more than one prey individual is required for the predator to complete its life cycle.”

Major types of insects that are predaceous: dragonflies and damselflies, mantids, true bugs, some thrips, lacewings and relatives, beetles, some wasps and ants, and some flies. Spiders and some mites are also important predators of arthropods.

3. Pathogens

The use of microbial pathogens has become a popular method of biological pest management.

Some pathogens used in biological control of insects:

Bacteria – Bacillus thuringiensis = Bt (many caterpillar pests, beetles, mosquitoes, others).

Viruses – Nucleopolyhedrosis viruses (Gypsy moth, European corn borer), granulosis viruses (Codling moth).

Fungi – Metarhizium (cockroach motels), Beauveria bassiana (Colorado potato beetle, Corn rootworms).

Protozoa – Nosema locustae (grasshoppers).

Nematodes – Steinernema and Heterorhabditis spp. (Soil weevils, Stem-boring caterpillars).

4. Herbivorous Insects and Microbial Pathogens of Weed Pests

Numerous species of plant-feeding insects have been evaluated for control of pest weeds. The greatest successes have been in rangelands, forests, and other natural habitats where other weed control approaches (e.g., herbicides, cultivation) are impractical or uneconomical. Some pathogens have also been looked at as weed biocontrol agents (e.g., plant rusts). The goal when using a weed biocontrol agent is generally one of weed population reduction and not eradication. Importation of a biocontrol agent from the region of origin of the weed has been the most common approach. It is generally a long-term process which requires consistent efforts, and can have long-term benefits.

Grow With Our Community

Managing pests through ecological balance takes time, observation, and shared knowledge. You do not have to navigate these organic agriculture practices alone. Join our CTAHRʻs webinars, and workshops to connect with other agricultural producers, share your experiences with cover crops, and access tailored organic agricultural insights with the Hānai'Ai.

# Implementing Organic Pest Management Practices #Biological Pest Control #parasitoids #IPM #systems agriculture