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. carneainstars 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.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. carneainstars 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.