Thrips (Thysanoptera: Thripidae) represent a major crop pest within agricultural systems. Green lacewings offer a promising option for biological control against thrips, and this article observes the dynamics of Chrysoperla externa‘s predation of Enneothrips flavens, one species of thrip.
The host plant in this experiment was peanuts (Arachis hypogaea). E. flavens causes seriouos damage to the plants; they live within closed buds or hidden parts of the plants, and then eat by puncturing and sucking. This leads to bug deformation and distortion, resulting in significant damage to the final crop.
C. externa is promising due to its abundance, voracious generalist eating habits, and pesticide tolerance. Additionally, it will inhabit several different agroecosystems.
This experiment observed three types of treatments: a control (no LW), T2 (C. externa eggs), and T3 (C. externa larvae), all of which had thrips introduced to them. Observational samples were made on day 0, 4, 9, and 15. These days were chosen as they follow the development of C. externa in the lab: four days for egg hatching, and then about three days per instar.
Results:
While the control plant didn’t increase in thrip population over time, C. externa did have notable effects on thrips. 
It also appears that it takes C. externa a few days before it notably impacts the pest populations, apparently regardless of whether they are released as eggs or in their first instar. This stands up to reason to an extent, as first instars don’t consume a significant amount compared to later instars.
Without predators, it is assumed that pest populations will generally increase. While this trend was not displayed here, it has been proven in other studies (Hassan 1977 is cited within the article, and is in relation to eggplants and aphids), and generally is the accepted trajectory of pest infestations. Additionally, it is notable that on day 15, the C. externa larvae began to pupate, and the thrip population began to increase slightly. For this reason, it is important to stagger releases or to make sure your ecosystems are attracting a wide variety of predators that have different life stages during different periods of time.
It is also notable that Chrysoperla spp may exhibit prey preferences, and further research is necessary to make substantive comment on the interaction strength between E. flavens and C. externa.