Sequential Rather Than Simultaneous Release of Trichogramma chilonis and Chrysoperla carnea for Management of Helicoverpa armigera

This study examined the functional response of second-instar Chrysoperla carnea larvae to Helicoverpa armigera eggs on tomato foliage and quantified reciprocal interference with the egg parasitoid Trichogramma chilonis under controlled laboratory conditions. Lacewing larvae were starved for 12 hours and exposed for 24 hours to five host-egg densities (10, 20, 40, 80, and 160 eggs per plant) with ten replicates per density, while interaction treatments assessed predation on unparasitized versus parasitized eggs and simultaneous predator–parasitoid exposure. Re-fitting the supplied means to the Holling Type II-disc equation produced an attack rate of 0.0402 h⁻¹, a handling time of 0.3879 h per egg, and a dimensionally consistent theoretical maximum consumption of 61.9 eggs per day (R² = 0.999), with consumption increasing from 8.2 to 43.8 eggs while the proportion consumed declined from 82.0% to 27.4% across the density gradient. Reciprocal interference was substantial and asymmetric: lacewing larvae consumed 28.6% fewer parasitized eggs compared to unparasitized eggs, while T. chilonis parasitism dropped from 58.7% when released alone to 34.2% in the presence of C. carnea, representing a 41.7% reduction reflecting both direct egg consumption and behavioural disruption of parasitoid foraging. These findings support sequential or spatially separated deployment rather than uncritical simultaneous release, with parasitoids prioritized during fresh oviposition and lacewings introduced later to target remaining eggs. Field validation remains essential before operational recommendations, as plant architecture and environmental conditions will modify laboratory-observed interactions. The quantified interference patterns provide a defensible mechanistic foundation for biological control decision-making, advancing understanding of natural enemy compatibility while offering practical guidance for integrated pest management in tomato production systems.