There are reports from Ohio farms that pyrethroid insecticides are no longer providing adequate control of Colorado potato beetles (CPB). Pyrethroids include Warrior, Baythroid, Brigade, Mustang Maxx, Asana, Pounce, and Ambush.
There are several newer insecticides that are effective for control of CPB populations, but most of these are best at killing the larvae rather than the adults of CPB. Products that provide good control of larvae are Agri-Mek (abamectin), Radiant (spinetoram), Coragen (chlorantraniliprole), Harvanta (cyclaniliprole), Rimon (novaluron), and Torac (tolfenpyrad).
A good biopesticide option for control of young larvae of CPB is Trident, which has Bacillus thuringiensis tenebrionis as the active ingredient. This is the same a.i. that was found in several products that are no longer readily available: Novodor and M-Trak. Trident is on the OMRI list of products allowed on organic crops. Other good options for control of CPB on organic crops are Entrust (spinosad) and azadirachtin products such as Aza-Direct, AzaGuard, Azatrol, Molt-X, and Neemix.
Among somewhat older insecticides, the neonicotinoids are still effective at most locations; these are listed in the table below. The neonicotinoids are generally more effective by soil application, which provide true systemic control, whereas application by foliar sprays provides translaminar control but not true systemic control throughout the plant. Some of the neonicotinoids are allowed only for soil applications, some for only foliar sprays, and some for either method. If used for soil application, usually at planting time, then later foliar applications are not allowed.
Table 1. Insecticides in the neonicotinoid group used for control of Colorado potato beetle on potato, eggplant, tomato, and peppers by soil or foliar application; ‘yes’ means allowed, ‘no’ means not allowed.
by Celeste Welty, Extension Entomologist