Compatibility of Cryptolaemus montrouzieri and insecticides for management of Planococcus citri

Citrus mealybug (Planococcus citri) is a greenhouse and nursery pest that was introduced to the United States in the late 1800s.  Previous research has shown that most chemical management techniques are ineffective, with only neonicotinoids showing above 50% mealybug mortality in our own greenhouse trials.  However, neonicotinoids can be harmful to pollinators and other beneficial insects.  Although biological control with mealybug destroyers (Cryptolaemus montrouzieri) reduces mealybug populations, the economic threshold for mealybugs on ornamental plants is extremely low.  To develop a management strategy that minimizes neonicotinoid use but is still able to adequately reduce mealybug populations, I evaluated combinations of mealybug destroyers, imidacloprid, and mineral oil in a greenhouse.  I hypothesized that using all three treatments together would be more effective than any individual treatment. If combining these treatments can suppress mealybug populations longer than imidacloprid by itself, fewer insecticide applications may be needed.  My research will make it easier for horticulturalists to continue growing the plants people love without overusing insecticides that can harm beneficial insects.