Native saltbush (Rhagodia spp.; Chenopodiaceae) as a potential reservoir for agromyzid leafminer parasitoids on horticultural farms

Abstract

Australia has to date been spared the introduction of highly polyphagous invasive pest agromyzid leafminers; however, their arrival and spread should be considered imminent. To develop a pre-emptive control strategy to deal with exotic leafminer outbreaks the first step is to identify Australian leafmining flies, their plant hosts and their parasitoids to gain an understanding of their population dynamics. Native vegetation may be providing resources for beneficial parasitic wasps plus access to alternative hosts and refuge from disturbance. Here, two Australian endemic saltbushes (Rhagodia candolleana and R. parabolica, Caryophyllales: Chenopodiaceae) have been investigated for their potential to act as reservoirs for endemic agromyzid hosts and their key parasitoids. Mined leaves of the two Rhagodia species were sampled on two commercial horticultural properties in the Virginia horticulture area on the Northern Adelaide Plains between September 2007 and April 2008. Leaf mines on both Rhagodia species were caused by an endemic leafminer species, putatively Phytoliriomyza praecellens Spencer (Diptera: Agromyzidae). Ten species of parasitoids (all Hymenoptera) emerged from R. candolleana mines and seven different species from R. parabolica mines, mainly from the family Eulophidae and with some Pteromalidae and Braconidae. Trigonogastrella Girault sp. (Pteromalidae), Zagrammosoma latilineatum Ubaidillah and Hemiptarsenus varicornis Girault (both Eulophidae) were the most abundant species on R. candolleana, whereas two Opius Wesmael spp. (Braconidae) were the most abundant species on R. parabolica. Findings from this survey suggest an opportunity to plant purpose-designed refuges that could play a role in conservation biological control as part of an Integrated Pest Management strategy developed prior to incursion of pest leafminers such as Liriomyza species.

Potential for biological control of the vegetable leafminer, Liriomyza sativae (Diptera: Agromyzidae), in Australia with parasitoid wasps

“…However, Z. latilineatum was one of the more abundant parasitoids in south‐eastern Australia, particularly in early autumn (Wood et al . ), and was the species most frequently reared from L. sativae in 2018 and 2019 on Thursday Island, Horn Island and Seisia (EI Pirtle, unpubl. data).…”

“…Wood et al . () found high levels of parasitism of Phytoliriomyza praecellens on revegetation plantings of Rhagodia candolleana and Rhagodia parabolica in Virginia, SA. Another unidentified Phytoliriomyza sp.…”

Australian native flowering plants enhance the longevity of three parasitoids of brassica pests

“…There is, however, growing interest in the use of plants that are native to a given area for habitat management. This lack is especially apparent in Australia, as no published information was found on assessing Australian native plant floral resources for benefits such as improving longevity, although a few field studies have shown the benefits of native vegetation as habitat for natural enemies (Stephens et al, 2006;Danne et al, 2010;Wood et al, 2010;Bianchi et al, 2015). Native plants may also be the focus of conservation efforts and will be more valuable than nonnative species in efforts to conserve or restore other native species including vertebrates (Fiedler et al, 2008;Isaacs et al, 2009;Landis et al, 2012), which themselves may serve as biological control agents (G amez-Viru es et al, 2007).…”

The effects of honey as a dietary supplement on the survivorship and nutrition-storing capacity of Hemiptarsenus varicornis (Hymenoptera: Eulophidae), a parasitoid of Liriomyza (Diptera: Agromyzidae) leafminers

“…More recently, Hemiptarsenus varicornis (Girault) (Hymenoptera: Eulophidae) has been discovered as a major parasitoid of L. trifolii in Japan (Saito et al, 1997;Arakaki and Kinjo, 1998;Ozawa et al, 2001). Hemiptarsenus varicornis is native to Japan, China, Vietnam, Indonesia, Australia and probably to other parts of East and South-East Asia (Konishi, 1998;Rauf et al, 2000;Prijono et al, 2005;Tran et al, 2007;Wood et al, 2010). Hemiptarsenus varicornis is native to Japan, China, Vietnam, Indonesia, Australia and probably to other parts of East and South-East Asia (Konishi, 1998;Rauf et al, 2000;Prijono et al, 2005;Tran et al, 2007;Wood et al, 2010).…”

“…Hemiptarsenus varicornis is native to Japan, China, Vietnam, Indonesia, Australia and probably to other parts of East and South-East Asia (Konishi, 1998;Rauf et al, 2000;Prijono et al, 2005;Tran et al, 2007;Wood et al, 2010). Parasitism of L. trifolii by H. varicornis is high in subtropical regions (Arakaki and Kinjo, 1998;Tran et al, 2007;Wood et al, 2010), and this parasitoid shows a high level of thermal tolerance (Hondo et al, 2006), suggesting that H. varicornis is a promising biocontrol agent for controlling leafminers in subtropical regions. Parasitism of L. trifolii by H. varicornis is high in subtropical regions (Arakaki and Kinjo, 1998;Tran et al, 2007;Wood et al, 2010), and this parasitoid shows a high level of thermal tolerance (Hondo et al, 2006), suggesting that H. varicornis is a promising biocontrol agent for controlling leafminers in subtropical regions.…”