Functional response and prey stage preference of Delphastus catalinae and D. pallidus (Coleoptera: Coccinellidae) on Bemisia tabaci (Hemiptera: Aleyrodidae)

Authors: KUMAR, VIVEK - University Of Florida; MEHRA, LUCKY - Kansas State University; McKenzie, Cindy; OSBORNE, LANCE - University Of Florida

Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/27/2020
Publication Date: 4/11/2020
Citation: Kumar, V., Mehra, L., McKenzie, C.L., Osborne, L. 2020. Functional response and prey stage preference of Delphastus catalinae and D. pallidus (Coleoptera: Coccinellidae) on Bemisia tabaci (Hemiptera: Aleyrodidae). Biocontrol Science and Technology. https://doi.org/10.1080/09583157.2020.1749833.
DOI: https://doi.org/10.1080/09583157.2020.1749833

Interpretive Summary: Natural enemies are a key component of an Integrated Pest Management program for Bemisia tabaci (Gennadius). The current study evaluated the biocontrol potential of two predatory beetles, Delphastus catalinae Horn and Delphastus pallidus LeConte, against the two most notorious cryptic species members of the Bemisia tabaci species complex, Middle Eastern Asia Minor 1 or MEAM1 and Mediterranean or MED. MEAM1 is formally known as biotype B whitefly and MED is formally known as biotype Q whitefly. The functional responses (at densities ranging from 20 -120 whitefly eggs per leaf disc) and prey-stage preferences (when offered varying ratios of whitefly eggs and nymphs) of the two beetles were investigated under laboratory conditions. Both predators showed Type II functional response with respect to MEAM1 and MED eggs, determined by the logistic regression model. Based on the estimates of handling time, attacking rate, and the number of eggs consumed, Delphastus catalinae seemed to be a more suitable biocontrol candidate for whitefly pests. Results indicated that both beetle species preferred whitefly eggs over the early nymphal instars and they could consume greater than 50 eggs per day. However promising, their feeding potential needs to be further investigated under greenhouse and semi-field conditions to confirm their efficacy potential.

Technical Abstract: Considering the importance of natural enemies in Integrated Pest Management program for Bemisia tabaci (Gennadius), in the current study we evaluated the biocontrol potential of two predatory beetles, Delphastus catalinae Horn and Delphastus pallidus LeConte, against Middle Eastern Asia Minor 1 (MEAM1) and Mediterranean (MED) whiteflies, the two most notorious cryptic species members of the B. tabaci species complex. The functional responses (at densities ranging from 20 -120 whitefly eggs per leaf disc) and prey-stage preferences (when offered varying ratios of whitefly eggs and nymphs) of the two beetles were investigated under laboratory conditions. Both predators showed Type II functional response with respect to MEAM1 and MED eggs, determined by the logistic regression model. Based on the estimates of handling time, attacking rate, and the number of eggs consumed, D. catalinae seemed to be a more suitable biocontrol candidate for whitefly pests. Results indicated that both beetle species preferred whitefly eggs over the early nymphal instars and they could consume >50 eggs per day. However promising, their feeding potential needs to be further investigated under greenhouse and semi-field conditions to confirm their efficacy potential.