Preliminary Observations on Zelus obscuridorsis (Stål) (Hemiptera: Reduviidae) as Predator of the Corn Leafhopper (Hemiptera: Cicadellidae) in Argentina

Abstract

The corn leafhopper Dalbulus maidis (Hemiptera: Cicadellidae), is an important corn pest in most of tropical and subtropical America. This leafhopper has a rich natural enemy complex of which parasitoids and pathogens are the most studied; knowledge on its predators is limited. We noted the presence of the native assassin bug Zelus obscuridorsis (Hemiptera: Reduviidae) predating diverse motile insects, including the corn leafhopper, on corn plants cultivated in household vegetable gardens in San Miguel de Tucumán (Argentina); in order to verify its predatory actions, we exposed lab-bred individuals of D. maidis to adults of Z. obscuridorsis. The predators were starved for 24 h before trials in which the corn leafhopper in different developmental stages were exposed. Zelus obscuridorsis is highly skilled in catching specimens in motion, but it was not able to prey on eggs. The predator was capable to catch and prey on nymphs and adults.

A taxonomic monograph of the assassin bug genus Zelus Fabricius (Hemiptera: Reduviidae): 71 species based on 10,000 specimens

“…Species of Zelus , among several other genera (e.g., Arilus Hahn, Sinea Amyot & Serville, and Montina Amyot & Serville), have been explored and studied as natural enemies in the Americas (Cohen and Tang 1997, Cogni et al 2002). Species of Zelus prey on a wide range of insects in cotton, corn, soybean, alfalfa crops and fruit trees in California and elsewhere (Ali and Watson 1978, McPherson et al 1982, Cisneros and Rosenheim 1998, Virla et al 2015), may reach population densities of up to 50,000 to 75,000/ha, and prevent outbreaks of lepidopteran larvae (Ables 1978). Hart (1972) conducted a taxonomic revision of Zelus with descriptions of twenty-five new species and twenty-six new synonyms, most of which remained unpublished (see Hart 1986, Hart 1987 for treatments of twenty Canadian, US, northern Mexican and Caribbean species).…”

Distribution of Dalbulus maidis (DeLong) (Hemiptera: Cicadellidae) and incidence of maize rayado fino virus and Candidatus Phytoplasma asteris in corn succession planting systems

“…This result was significantly superior to the results found in our study. Differences in population density can be related to the action of natural enemies and local environmental factors driving the life history of invasive insects such as D. maidis 37–39 …”

“…Differences in population density can be related to the action of natural enemies and local environmental factors driving the life history of invasive insects such as D. maidis. [37][38][39] The incidence of maize bushy stunt phytoplasma was greater in Crop 3 than in Crop 2, but disease incidence was concentrated around the edges of both fields (Fig. 5).…”

Miscelanea 152 (2024): Dalbulus maidis (Hemiptera: Cicadellidae), vector of corn stunt disease: Relevant biological aspects, with special reference to knowledge generated in Argentina

“…En Argentina, hasta el momento, se cuenta con dos aportes científicos que señalan el accionar de depredadores del vector: la tijereta Doru lineare (Eschs.) (Dermaptera: Forficulidae) (Mariani et al, 1997) y la chinche asesina Zelus obscuridorsis (Stål) (Hemiptera: Reduvidae) (Virla et al, 2015). Durante la explosión demográfica ocurrida en estos últimos meses (2023-2024), a través de las redes sociales se ha documentado el accionar de numerosos depredadores como, por ejemplo: arañas, larvas de Chrysopidae (Neuroptera), adultos de Coccinellidae (Coleoptera), y adultos de chinches depredadoras de diversas especies, en particular Geocoridae y las del género Orius (Anthocoridae) (Figura 10).…”