Whitefly Species Preferences of the Predatory Ladybird Beetle, Delphastus pallidus LeConte (Coleoptera: Coccinellidae)

TL;DR

This study shows that Delphastus pallidus, a ladybird beetle, can prey on seven whitefly species, making it a promising natural pest control agent.

Contribution

The study documents D. pallidus as a potentially native U.S. predator of multiple whitefly species, including both waxy and non-waxy types.

Findings

D. pallidus prefers Bemisia tabaci over other whitefly species.

The beetle feeds on both waxy and non-waxy whiteflies, indicating broad biocontrol potential.

This is the first study to document D. pallidus as a native U.S. predator of at least seven whitefly species.

Abstract

Delphastus is a genus of small coccinellid beetles that specialize in whiteflies. Recent surveys have documented an increased abundance of the potentially native United States species Delphastus pallidus, which feeds on multiple whitefly species in South Florida. In controlled preference trials, we identified seven whitefly species as suitable prey. Bemisia tabaci was the most strongly preferred. These results show that D. pallidus accepts both waxy and non-waxy whiteflies, indicating its promise as a biological control agent for a range of whitefly pests.

Delphastus Casey (Coleoptera: Coccinellidae: Serangiini) comprises small predatory ladybird beetles that feed on immature whiteflies. Several Delphastus species are utilized as biological control agents. However, Delphastus pallidus (LeConte) has been understudied for the past several decades. Recent landscape surveys in South Florida revealed a marked increase in D. pallidus populations associated with multiple whitefly species. We evaluated whitefly species preferences of D. pallidus using choice and no-choice assays conducted in incubators and insectaries. Seven whitefly species were confirmed as prey and ranked in order of preference: Bemisia tabaci Gennadius > Aleurothrixus trachoides (=Aleurotrachelus trachoides) (Back) > Singhiella simplex (Singh) > Paraleyrodes bondari Peracchi > Aleurodicus rugioperculatus Martin > Asiothrixus antidesmae (Takahashi) > Aleurodicus dugesii Cockerell. Findings indicate that D. pallidus feeds on a taxonomically and morphologically diverse set of whiteflies, including both waxy and non-waxy species, which likely facilitates establishment and dispersal in ornamental and agricultural landscapes. This study is the first to document D. pallidus as a potentially native U.S. predatory beetle that attacks at least seven whitefly species. Knowledge of its prey preferences will inform mass-rearing strategies and potential deployment for whitefly biocontrol.

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