Biology of the Armored ScaleRhizaspidiotus donacis(Hemiptera: Diaspididae), a Candidate Agent for Biological Control of Giant Reed

Abstract

The development, survival, and reproductive output of the armored scale Rhizaspidiotus donacis Leonardi (Hemiptera: Diaspididae) were determined as part of an evaluation of this scale for biological control of giant reed, Arundo donax L. Scale crawlers produced by females collected in southern France and Spain lived for less than two d in the absence of a host. On A. donax shoots held under a diurnally variable temperature regime (15–26°C), crawlers settled on leaf collars and axillary stem bases and completed the first instar within 14 d. Winged adult males emerged within six wk and lived 1.7 d in vials. Immobile adult females were observed 75 d after crawler release. Development time to adult was reduced 15% in males and 28% in females when scales were reared at a constant temperature of 26°C. Survival from crawler to adult was 20–25%. The generation time for laboratoryreared females was 170d and their average life span was 203 d. Females from field collections produced an average of 85 live crawlers, 2.7-fold more than did colony-reared females. Across 31 field collections, female size was correlated to the percentage of scales that were reproductive. However, among eight collections from two Spanish sites, size varied but was not correlated to reproductive success. Peak reproduction from field collections occurred between November and March, and the scale completed two generations per year. Biological information about R. donacis will aid production, release, and field evaluation of this scale for biological control of invasive A. donax in North America.

Evaluation of Spanish Arundo scaleRhizaspidiotus donacis(Hemiptera; Diaspididae) survival and fecundity on three new world genotypes ofArundo donax(Poaceae; Arundinoideae)

“…Counts of first-generation scales were combined across sample date dissections (60 or 180 days post-infestation) as prior tests (Moran & Goolsby, 2010) had shown that immature and adult female survival varied little beyond 60 days post-crawler release. Male scales had already completed their development by that time, and were observed in dissections as empty scale covers.…”

“…One of the key biological control agents released against giant reed is the arundo scale, Rhizaspidiotus donacis Leonardi (Hemiptera: Diaspididae; Goolsby et al, , 2011Moran & Goolsby, 2010). Sessile females produce mobile crawlers that colonise rhizomes and stems where they consume plant cell contents, reducing plant photosynthesis (Moore, Watts, & Goolsby, 2010) and stand vigour (Kirk, Widmer, Campobasso, Carruthers, & Dudley, 2003).…”

“…Based on the life cycle as determined by Moran and Goolsby (2010), numbers of scales in the second generation were counted 180 days or more after original crawler infestation, using a subset of the rhizomes of the same Texas accessions used to evaluate first-generation scale numbers. To assess first-generation reproduction, mature females (up to 50 per rhizome, depending on availability) were isolated individually from each of these rhizomes in gelatin capsules and the numbers of neonate crawlers produced were counted.…”

An international borderland of concern: Conservation of biodiversity in the Lower Rio Grande Valley

“…20A), including the LRGV (Owens and others, 2005;Seawright, Rister, Lacewell, McCorkle, and others, 2009;Seawright, Rister, Lacewell, Sturdivant, and others, 2009). Giant reed displaces native plant species, forms dense monocultures in riparian areas and other wetland habitats, and transpires large amounts of water (Owens and others, 2005;Seawright, Rister, Lacewell, McCorkle, and others, 2009) , and Lasioptera donacis [arundo gall midge]) that might be used to reduce giant reed (e.g., Goolsby and Moran, 2009;Seawright, Rister, Lacewell, McCorkle, and others, 2009;Seawright, Rister, Lacewell, Sturdivant, and others, 2009;Moran and Goolsby, 2010;Poinar and Thomas, 2014). In June 2015, the Governor of Texas signed a bill directing the Texas State Soil and Water Conservation Board to develop a program to eradicate giant reed along the Rio Grande (K. Wahl, pers.…”

Rhizaspidiotus donacis (Hemiptera; Diaspididae); agente con licencia para controlar. Primeros resultados del plan de control biológico del carrizo gigante en Estados Unidos

“…Estas observaciones resultaron coincidentes con los estudios sobre su biología desarrollados en las cuarentenas (MORAN & GOOLSBY, 2010). Aunque aún preliminares, estos datos indican que la primera iniciativa de uso de un diaspídido como agente de control biológico para el control de una planta invasora, puede contribuir significativamente a una solución definitiva.…”