Potential of Lacewings (Neuroptera: Chrysopidae) as Predators of the Red Gum Lerp Psyllid Glycaspis brimblecombei (Hemiptera: Aphalaridae) in Eucalyptus

Abstract

The productivity of eucalyptus is threatened by several pests, including the red gum lerp psyllid, Glycaspis brimblecombei, which causes significant losses in forest systems. In Brazil, the lacewings Ceraeochrysa cubana and Chrysoperla externa are common in eucalyptus plantations, but little is known about the behavior of these predators toward the red gum lerp psyllid. This study evaluated the predatory behavior of larvae of both lacewing species on psyllid eggs and nymphs. Subsequently, the predatory capacity and functional response of C. externa were determined in relation to different developmental stages of the psyllid. Predatory capacity was studied for 2nd and 3rd instar larvae of C. externa using eucalyptus leaves naturally infested with 2nd and 3rd instar nymphs of G. brimblecombei. For the functional response, 3rd instar larvae, 24 h after ecdysis, were supplied with psyllid eggs at densities of 1, 2, 4, 8, 16, and 32 eggs per predator larva. The results showed that larvae of both predators exhibit differences in their behavioral parameters, regardless of the developmental stage. Chrysoperla externa larvae are capable of preying on eggs and nymphs in the early instars of the red gum lerp psyllid. The 2nd and 3rd instar larvae of C. externa consumed an average of 19.75 and 38.4 nymphs, respectively. Third instar larvae of C. externa exhibited a type II functional response when fed with different egg densities. Our results suggest that C. externa is a potential control agent for eggs and early instar nymphs of G. brimblecombei. For C. cubana, further studies are necessary to determine its potential in controlling this pest.

Keywords: Ceraeochrysa cubana; Chrysoperla externa; Behavior; Forest pests; Predation; Predators.