Generalist control agents often had non-target negative effects on other beneficial insects, whereas specialist control agents disappeared as their target pest resource was eliminated 7, 8. However, both in practice and theory, biological control was difficult to stabilize 3, 4, 5, 6. Since then, there have been many attempts to mimic such natural systems in agriculture by releasing natural enemies of pests as biological control agents to capture the control mechanisms that presumptively led to the stability of natural systems 2. Contrary to expectations, the inclusion of negative interactions, which are arguably a necessary consequence of increased complexity, can stabilize unstable conditions and rescue biological control of simpler, ineffective pest management systems.Ĭharles Elton 1 first juxtaposed the striking stability of natural systems and the plagues of diseases and pests so common in agricultural systems in 1958. Here we show that combining two unstable two-dimensional systems (pest–predator and pest–pathogen) produces a stable three-dimensional system (pest–predator–pathogen) that is robust to perturbations in initial conditions. Early experience with biological control was hampered significantly by the inherent instability of many of the control agents, suggesting that pursuit of the autonomous strategy could be difficult. One generalized philosophy that has gained currency in recent years is autonomous pest control, in which complex ecological interactions are encouraged to maintain the ecosystem in a state of permanence with the pest below economic thresholds. We therefore recommend release of these two biocontrol agents in North America.It has long been a goal of farm policy to manage production in such a way that expensive off-farm inputs and negative environmental consequences can be simultaneously minimized. neurica attack to be far smaller than allowing expansion of invasive P. australis americanus demography due to A. Phragmites populations in the southern US, particularly along the Gulf of Mexico, occur outside the climate range of these two temperate moth species. The native subspecies is further safeguarded by increased mortality of eggs and larvae when laid on, or developing in P. Open field multiple-choice oviposition tests affirmed this moths laid 6.5% of their eggs on native P. No-choice tests or tests in small cages provided inconsistent results, but both moths showed consistently high preferences for introduced P. Both moth species are specific to the genus Phragmites and both show a very strong, but not absolute, preference for invasive P. We used extensive multi-pronged investigations in Europe and North America to evaluate host specificity and impact of two European stem mining noctuid moths, Archanara geminipuncta and A. Allowing continued expansion does not only threaten native wetland biota but also an endemic North American subspecies Phragmites australis americanus. Invasive Phragmites australis is widespread in North America and despite decades of management and large annual expenditures (>5 million US$) using physical and chemical means, local populations and the species range are expanding.
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