Mealybugs are a serious pest in many high-value crops, including citrus, grapes, and ornamentals. Their waxy coating and cryptic behaviour make them difficult to control with conventional methods. Fortunately, biological control using natural enemies like Cryptolaemus montrouzieri (CRYPTO-TEC) and Anagyrus vladimiri (ANA-TEC), has proven to be a sustainable and effective solution.
However, there’s one often overlooked factor that can make or break the success of a biocontrol program against mealybugs: Ants.
The Ant-Mealybug Relationship: A Symbiotic Shield
Ants and mealybugs have a mutualistic relationship. Mealybugs excrete honeydew, a sugary substance ants love. In return, ants protect mealybugs from predators and parasitoids, often aggressively attacking any biocontrol agents that approach.
This ant protection severely hampers the establishment and effectiveness of biological control agents. In fact, uncontrolled ant populations can completely neutralize even the most carefully planned biocontrol strategies.
How Ants Interfere With Biocontrol
Disruption of Parasitoid Activity
Parasitic wasps lay their eggs inside mealybugs. Ants, however, will chase away or kill these wasps before they can parasitize.
Predator Deterrence
Predators like Cryptolaemus montrouzieri larvae are vulnerable to ant aggression. Ants often drive them away from mealybug colonies, significantly reducing feeding and control success.
Promotion of Mealybug Spread
By protecting mealybug populations, ants indirectly contribute to their spread, especially during early infestations when timely biocontrol intervention is most critical.
What Growers Can Do: Ant Management Is Key
Effective mealybug management must include ant control. Here are proven strategies:
Use Ant Baits Wisely: Deploy protein-based or sugar-based ant baits near tree trunks and along row borders. These target the ant colony without disrupting beneficials.
Create Physical Barriers: Apply sticky bands or insect glue barriers to trunks to prevent ants from accessing canopies where mealybugs and their enemies are found.
Prune Bridges: Remove any weeds, branches, or grass touching tree canopies — these can serve as pathways for ants to bypass treatments and reach mealybugs.
Strategic Timing: Ant control should begin before releasing biological control agents to ensure the agents can establish and operate without harassment.
Integrated Approach for Long-Term Success
Combining ant suppression with timely releases of natural enemies provides the best chance for sustainable mealybug management. At Insectec, we supply a full range of mealybug-targeting biocontrol agents and can assist with customized release plans.
Biological control of mealybugs is a powerful tool but without controlling ants, you’re fighting an uphill battle. By incorporating proactive ant management, growers can unlock the full potential of their biological control programs and move one step closer to more sustainable, resilient farming systems.