RR (Raghavendra Reddy) Manda MSc

Raghavendra Reddy Manda is a Doctoral Researcher at Wageningen University & Research, specializing in biological control of invasive stink bugs, particularly Nezara viridula and Halyomorpha halys, in Dutch greenhouses. He is based at the Business Unit Greenhouse Horticulture & Flower Bulbs in Bleiswijk and the Laboratory of Entomology in Wageningen. His work focuses on screening and evaluating novel arthropod predators, establishing arthropod predators in greenhouses, and optimizing ecological interactions within the greenhouse food web to enhance pest control efficiency.

Biological Control in Greenhouse Ecosystems

Effective biological control extends beyond simply introducing natural enemies into greenhouses. The success of such programs depends on creating an environment that supports the establishment and persistence of natural enemies. This involves providing essential resources such as alternative food sources, refuges, and breeding sites, ensuring that natural enemies (specially the generalists) remain active even before pest outbreaks occur.

A key strategy in greenhouse arthropod pest management is the preventive establishment of natural enemy populations, often referred to as a "standing army"—a proactive approach where natural enemies are already present and capable of suppressing emerging pest populations before they reach damaging levels.

Harnessing Biodiversity for Sustainable Pest Control

Greater biodiversity among natural enemies enhances pest suppression, especially when they occupy different but complementary feeding niches. Complementarity occurs when enemies target different pest species, life stages, or locations, or use distinct hunting strategies. This ties into ecological theory of species richness, which suggests that increased species diversity improves ecosystem functioning. More diversity among natural enemies can enhance herbivore suppression in two key ways: the 'sampling effect' and 'species complementarity.' The sampling effect means that more diverse communities are more likely to include particularly effective resource extractors. While, species complementarity, on the other hand, means that different predators use resources in distinct ways, leading to better resource exploitation overall.

Optimizing the Ecological Interactions to Maximize Biocontrol Efficiency in Greenhouses

While biodiversity in natural enemies can strengthen pest suppression, it also introduces complex ecological interactions such as intraguild predation—where predators prey on each other. This can disrupt pest control, especially when larger, dominant predators consume smaller but highly effective biocontrol agents. For example, active-hunting predators may become prey for ambush predators, potentially weakening overall pest suppression.

To develop resilient and effective biological control programs, it is crucial to study and manage the interactions among the (important) natural enemies within the greenhouse ecosystem. By carefully selecting compatible natural enemies and optimizing their ecological relationships, biological control strategies can be refined to enhance pest suppression while minimizing unintended disruptions.