Biocontrol Potential of a Commercially Available Predator Rhyzobius lophanthae Blaisdell (Coleoptera: Coccinellidae) Against Diaphorina citri Kuwayama (Hemiptera: Liviidae)

<i>Diaphorina citri</i> Kuwayama is a key pest of citrus and insect vector of Huanglongbing (HLB), also known as citrus greening disease, causing significant losses in Florida and other regions. The naturally occurring effective ladybeetle predators and their impact on <i>D. citri</i> reduced from years of insecticide use against this pest and are not available commercially. Additionally, most species are large-sized, while most eggs and neonates of <i>D. citri</i> are in hard-to-reach locations such as unopened leaves, which makes access difficult for them. We evaluated a commercially available small-sized predatory ladybeetle <i>Rhyzobius lophanthae</i> Blaisdell against <i>D. citri</i> immatures. A single adult consumed an average of 24.9 eggs and 8.7 first and second instar nymphs of <i>D. citri</i> within 24 h. Beetles exhibited Type II functional response against nymphs with an attack rate of 0.92 h^-1 and a handling time of 0.08 h. Their consumption rate increased with nymphal density up to twenty per shoot. In the field test, beetles lived 10 days longer when confined with new shoots infested with <i>D. citri</i> immatures in a voile fabric sleeve cage in citrus trees every two days, versus seven days. In an open field release of <i>R. lophanthae</i> in a citrus orchard, these ladybeetles were found foraging in sentinel and neighboring trees infested with <i>D. citri</i>. The consumption rate of <i>R. lophanthae</i> on <i>D. citri</i> immatures and its survival in Florida orchards suggest its potential for biological control and Integrated Pest Management.