This article highlights the key role of public insectaries in biological control as a sustainable tool for crop protection.

Introduction:

At the heart of sustainable and resilient agriculture lies an age-old strategy now reinvigorated by science: biological control. Faced with the challenge of managing pests that threaten high-value crops like citrus, public insectaries today play a key role in the production, acclimatization, and distribution of beneficial insects. These natural enemies act as predators or parasitoids of pests, contributing to ecological balance and the reduction of pesticide use.

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What is biological control?

Biological control involves the use of living organisms —predators, parasitoids, or pathogens— to keep pest populations below their economic damage threshold. This strategy is part of integrated pest management (IPM) programs and can take several forms:

• • Conservation biological control: Enhancing native populations of natural enemies through practices that improve their habitat or reduce interfering factors (e.g., avoiding broad-spectrum pesticides).

• • Classical biological control: Introducing exotic species that have been previously evaluated and acclimatized, aiming for their permanent establishment in the agricultural ecosystem.
    
    
  • Inoculative biological control: Releasing small amounts of natural enemies early in the crop cycle, expecting them to multiply in situ.
    
    
  • Inundative biological control: Releasing large numbers of natural enemies when pest populations have already reached critical levels.

To implement biological control, insectaries are essential.

What is an insectary?

Insectaries are facilities where beneficial insect species are bred to combat future pests. These enclosed spaces simulate natural conditions, providing the right environment for insects to grow and reproduce. They are typically dark, climate-controlled rooms that regulate temperature, humidity, and other variables. Insects are also provided with the necessary food to support their development. Once they are ready, they are released into the natural environment to fulfill their pest control function.

The role of public insectaries

Public insectaries are a vital strategic resource for biological pest control in agriculture. For citrus crops—high in economic value and widely grown in regions like the Valencian Community, Andalusia, and Murcia—the use of natural enemies is increasingly promoted by government agencies.

A key example is the work done by the insectaries of the Generalitat Valenciana, located primarily in Silla (Valencia) and Almassora (Castellón). These centers operate on two complementary fronts:

1. Classical biological control and acclimatization

Public insectaries are a vital strategic resource for biological pest control in agriculture. For citrus crops—high in economic value and widely grown in regions like the Valencian Community, Andalusia, and Murcia—the use of natural enemies is increasingly promoted by government agencies.

A key example is the work done by the insectaries of the Generalitat Valenciana, located primarily in Silla (Valencia) and Almassora (Castellón). These centers operate on two complementary fronts:

2. Inundative biological control and farmer distribution

Insectaries also breed predators that do not establish themselves permanently but are effective for targeted control. Examples include:

• Cryptolaemus montrouzieri: The “mealybug destroyer,” used against Planococcus citri and other pseudococcids.
• Rodolia cardinalis: Used to control Icerya purchasi (cottony cushion scale).

Nursery Insectaries: A Collaborative Network

Beyond breeding and distribution, public insectaries foster collaboration with farmers and institutions interested in breeding natural enemies independently. This model, known as the "nursery insectary," decentralizes auxiliary fauna production.

Participants receive both insects and technical training, with the commitment to raise them non-commercially and use them for biological control in their own or associated agricultural holdings.

You can find the steps to become a collaborating insectary on the Generalitat's official platform.

Currently, the application period is open for Cryptolaemus montrouzieri to help control present mealybug species.

What Species Are Currently Bred?

The list of beneficial insects reproduced in Valencian public insectaries includes:

• Cryptolaemus montrouzieri
  
• Rodolia cardinalis
  
• Chilocorus bipustulatus
  
• Coccidophilus citricola
  
• Encarsia perniciosi
  
• Comperiella bifasciata
  
• Psyttalia concolor
  

Each species targets specific pests. It's crucial to understand their release conditions and compatibility with plant protection products.

Compatibility with Pesticides: A Key Factor

The success of biological control largely depends on minimizing the side effects of pesticides on beneficial fauna. Government agencies provide tools to check authorized active substances and recommended preharvest intervals to avoid harming released insects.

There are also up-to-date studies on the side effects of various pesticides on beneficial insects in citrus crops. These reference tables are essential to adjust conventional treatments to integrated strategies. You can check the information here.

1 Cryotolemus  predating

2 South Africa Mealybug damage

3 Mealybug damage on ripe fruit. Photo: Generalitat Valenciana

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Cryptolaemus montrouzieri: A Success Story

Cryptolaemus montrouzieri is a beetle from the family Coccinellidae, predatory at all life stages of several mealybug species such as Planococcus citri, Planococcus ficus, Pseudococcus longispinus, Pseudococcus viburnii, and Delotococcus aberiae, among others. These mealybugs mainly affect citrus, damaging fruit and significantly lowering yields, causing major economic losses.

Originally from Australia, this insect was introduced successfully in the U.S. in 1892 and later in Spain in 1927, via the Burjassot insectary (Levante Plant Pathology Station). According to the technical report by Federico Gómez Clemente, one of Spain's first milestones in citrus biological control occurred in 1929 when Cryptolaemus was released in the Agricultural Colony of San Pedro de Alcántara, Málaga. The acclimatization was a total success:

• The following spring, beetles emerged en masse from winter shelters and invaded citrus groves.
• The impact was immediate and overwhelming — the mealybug population was wiped out, and the beetles even spread across the ground in search of food, which was no longer available.
  
  

This not only demonstrated the effectiveness of Cryptolaemus, but also the value of public insectaries capable of breeding and distributing these predators at the right time.

Today, both public and collaborative insectaries continue producing Cryptolaemus. The Ministry of Agriculture provides guidelines to ensure effective releases. For instance:

• Recommended dose: 2,000 individuals per hectare.
• Perform two releases 10–12 days apart.
• Distribute insects evenly and focus on infested areas.
• Release adults inside trees, avoiding midday heat.
• Check for larvae 15–20 days after release.
• Manage ant populations, which can hinder effectiveness.
• Release insects immediately upon receipt, or store at 10–15 ºC for no more than 48 hours.

Conclusion

The path to sustainable, resilient agriculture depends on eco-friendly control strategies, with biological control playing a central role. Public insectaries, promoted by governments, show that effective, safe, and accessible biological control programs are not only possible—they’re already happening.

Success stories like Cryptolaemus montrouzieri—past and present—prove the immense potential of these initiatives.

Moreover, the nursery insectary model and collaboration between governments, technicians, and producers help build an agroecological network that empowers citrus growers and reduces dependency on chemical inputs. Releasing beneficial insects at the right time, in proper doses, under the best technical conditions, improves pest control and promotes functional biodiversity on farms.

Investing in knowledge, training, and collaborative networks is as crucial as breeding insects. The success of biological control lies in everyone’s hands. In a context of climate change, environmental regulation, and market demands, insectaries are—now more than ever—natural allies in citrus defense.