Consumption of Immature Stages of Colorado Potato Beetle by Chrysoperla Carnea (Neuroptera: Chrysopidae) Larvae in the Laboratory

The Colorado potato beetle (CPB), Leptinotarsa
decemlineata (Say), has been an important defoliator of potatoes
for 150 years. Although the use of insecticides allowed
drastic reductions of CPB populations, resistance development
against active substances has been observed. In this
context, biological control using predatory larvae of the lacewing
may represent a good alternative. CPB egg and larval
consumption rates have been evaluated for all Chrysoperla
carnea (Stephens) instars for 24 h. While first and second C.
carnea instars only consumed eggs (1.3 and 1.8), first (1.5 and
2.4) and second (0.6 and 0.8) CPB instars, third instar of
lacewing consumed all CPB immature stages: 6.8 CPB eggs,
8.5 first, 4 s, 0.5 third and 0.1 fourth CPB instars. This third
instar killed 4-fold more CPB larvae than other larval stages.
Handling time for third instar lacewing has been evaluated at
52 min on first instar CPB, 102 min on second instar and
164 min on third instar. Our laboratory assays highlight a
potential for lacewing larvae to control CPB immature stages
with a greater efficiency on young CPB larval stages. Fields
assays are however needed to confirm efficiency of this CPB
natural enemy under field conditions.