Potential to use Chrysoperla externa (Neuroptera: Chrysopidae) fed with Diatraea saccharalis (Lepidoptera: Crambidae) in Agroecological Systems

Abstract

The objective of this work was to evaluate the biological development of larvae of Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae) on Diatraea saccharalis (Fabricius, 1764), (Lepidoptera: Crambidae) and Eggs Anagasta kuehniella (Zeller, 1979) Lepidoptera: Pyralidae) checking duration in days of the larval and pupal phase and, the weight (mg) of the larvae every 24 hours of the instar exchange. The treatments were: T1: C. externa fed with A. kuehniella eggs (standard); T2: C. externa fed with 1st instar caterpillars of D. saccharalis; T3: C. externa fed with 2nd instar larvae of D. saccharalis, T4: C. externa fed with 3rd instar larvae of D. saccharalis, the design was completely randomized, containing 4 treatments with 5 replicates containing 6 insects. The duration of the larval period, the immature stage and the weight of the larvae were of 10.5 days, 20,30 days and 5.6 mg; 10.0 days, 19.70 days and 6.3 mg; and 9.70 days, 19.40 days and 7.1 mg; 10.3 days, 20.30 days and 8.3 mg for larvae fed A. kuehniella eggs and D. saccharalis larvae on the first, second and third instars, respectively. It was verified that the size of the prey, although not influencing the immature period of C. externa larvae, when compared to the conventional use with A. kuehniella eggs, had an effect on the weight of the larvae of the same, to the extent that the development of its prey grew. Conclude that C. externa has potential to be fed with D. saccharalis being another alternative for agroecological systems.