Green lacewing Chrysoperla rufilabris (Neuroptera: Chrysopidae) is a potential biological agent for crapemyrtle bark scale (Hemiptera: Eriococcidae) pest management

Green lacewing Chrysoperla rufilabris (Neuroptera: Chrysopidae) is a potential biological agent for crapemyrtle bark scale (Hemiptera: Eriococcidae) pest management

Crapemyrtle bark scale (CMBS; Acanthococcus lagerstroemiae), an invasive sap-sucking hemipteran, has spread across 16 U.S. states. Infestation of CMBS negatively impacts the flowering and reduces the aesthetic quality of crapemyrtles. The widespread use of soil-applied neonicotinoid insecticides to suppress the CMBS infestation may be hazardous to pollinators and other beneficial insects. Natural enemies of CMBS are important agents for developing integrated environmentally friendly management strategies. This study evaluated the performance of larval green lacewing (Chrysoperla rufilabris) as a biocontrol agent of CMBS. Predatory behavior of the larval C. rufilabris upon CMBS was documented under a stereomicroscope using infested crapemyrtle samples collected from different locations in College Station, TX (Figure 1).

Figure 1. Observations of Chrysoperla rufilabris were reported at different locations on Texas A&M campus. Larval C. rufilabris were observed preying on CMBS gravid females during the landscape investigations on April 9th (A) (30°36′39″ N, 96°20′58″ W) and June 28th (B) (30°36′55″ N, 96°20′24″ W); Lacewing eggs were found in CMBS-infested crapemyrtles on Oct 18th (C) (30°37′03″ N, 96°20′08″ W) and Nov 15th, 2019 (D) (30°36′30″ N, 96°21′02″ W).

Predation potential of C. rufilabris upon CMBS eggs and foraging performance using Y-maze assay were investigated under laboratory conditions. Results confirmed that larval C. rufilabris preyed on CMBS nymphs, eggs, and adult females (Figure 2).

Figure 2. Larval Chrysoperla rufilabris preying on CMBS under laboratory conditions. Larva of C. rufilabris targeted a female adult of CMBS (A) and voraciously seized and consumed body fluids of the CMBS using its large, sucking jaws (B) after placing them in the same Petri dish. A green lacewing larva easily grabbed a CMBS egg (C) and consumed the egg in about 1min (D) after being transferred to the same Petri dish. Larva seized a crawling nymphal CMBS (E) and consumed it quickly (F) under the same experimental conditions.

The evaluation of predation potential results showed that 3rd instar C. rufilabris consumed significantly more CMBS eggs (176.4 ± 6.9) than 2nd (151.5 ± 6.6) or 1st instar (11.8 ± 1.3) in 24 hours (Table 1).

Table 1. Feeding Duration and Numbers of CMBS Eggs Consumed by Chrysoperla rufilabris at Different Developmental Stages.
z Means ± SE (N=3, representing a total of 60 tested for each developmental stage), in the same column, followed by different letters are significantly different as determined by Tukey’s HSD test (α =0.05).

Results from the Y-maze assay indicated that larval C. rufilabris could target CMBS in the dark, indicating that some cues associated with olfactory response were likely involved (Figure 3).

Figure 3. Foraging performance test in 24-h Y-mazes. A: The foraging performance index (FPI) of C. rufilabris in the 24-h Y-maze assay was 0.56 ± 0.09 (mean ± SE); B: Among the lacewings that made a choice, 78.14 ± 4.74% larval C. rufilabris successfully targeted CMBS in the dark.

In summary, this study is the first report that validated C. rufilabris as a natural predator of CMBS and its potential as a biological agent to control CMBS. Future investigation of how the olfactory response of larval C. rufilabris to CMBS would benefit the development of environmentally friendly strategies to manage CMBS.


To access the full article for details, please visit https://doi.org/10.48130/TIH-2022-0003

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