Microarthropods in australian sugarcane soils: A survey with emphasis on the Mesostigmata as potential regulators of nematode populations

Abstract

Sugarcane is attacked by a suite of nematode pests, but little is known of the mites and other soil microarthropods that feed on them. To address this deficit, we undertook a survey of the soil microarthropod fauna in 60 sugarcane fields in Queensland, Australia. The results showed that oribatid mites and springtails dominated the upper 10 cm of sugarcane mineral soils. Laboratory observations demonstrated avid nematophagy in Galumnidae (Galumna sp., Pergalumna sp.), Scheloribatidae (Scheloribates sp.), and one unidentified Isotomidae (Collembola). Mesostigmata, a group of mites with many known nematophages, were never very abundant. Most of the taxa identified were previously known from Australia, but Protogamasellus sigillophorus Mineiro, Lindquist and De Moraes is reported for the first time and was reared through several generations on nematodes. In addition, we reared ten other cane field mesostigmatans on nematodes: Antennolaelaps sp., Asca garmani, Asca major, Cheiroseius sp., Cosmolaelaps sp., Gaeolaelaps sp., Gamasellodes bicolor, Gamasiphis sp., Holaspulus tenuipes, Protogamasellus mica. Because Mesostigmata were present at higher population densities in mineral soil where a mulch layer was retained after harvest, we assessed the effect of mulching in two sugarcane fields. Mulching did not result in significant differences in total microarthropods in the upper 5 cm of mineral soil. However, the mulch contained large numbers of free-living nematodes and 10% of the microarthropods were nematophagous mites. Results from a pot experiment also suggested that differences in soil properties affect nematophagous mite communities. More microarthropods and greater numbers of Mesostigmata were recovered from a well-structured clay loam soil than a sandy loam soil, and populations were highest in surface soils with high carbon contents and high levels of microbial activity.

Review: predatory soil mites as biocontrol agents of above- and below-ground plant pests

“…The current literature shows that predatory soil mites can be included in biocontrol programs, but methods must, and can be, improved. One such improvement is the use of a litter/mulching layer to increase the persistence of the predators in a cropping system (Muñoz-Cárdenas et al 2017 ; Esteca et al 2018 , 2020 ; Walter and Stirling 2018 ; Navarro-Campos et al 2020 ). Another is the supply of alternative food for the predators in the soil, guaranteeing persistence of their populations when pest densities are low.…”

“…The litter layer is usually removed in many greenhouse crops because it can be a source of pests, pathogens, and toxic compounds (Mercier and Manker 2005 ; Cartenì et al 2016 ). However, it could be kept to promote the establishment of predatory soil mite populations (Muñoz-Cárdenas et al 2017 ; Walter and Stirling 2018 ; Esteca et al 2020 ; Navarro-Campos et al 2020 ). We suggest that applying litter or mulch to artificial substrates in soilless crops can promote the presence and persistence of soil predators, thus increasing their role in pest control.…”

Review of the genus Gamasellodes Athias-Henriot (Mesostigmata: Ascidae) in Russia, with a description of a new species

“…This may suggest that G. brevisetus sp. n. may be a predator of nematodes, like its congeners in the USA and Australia (Walter 1987;Halliday et al 1998;Walter and Stirling 2018). We stress that further comprehensive field studies and experimental work are needed to find more species of this genus and establish the role of this mite in its respective ecosystems.…”

“…Within the Ascinae subfamily, the genus Gamasellodes Athias-Henriot, 1961 is presumed to be a group of the smallest predatory mites feeding upon nematodes or small arthropods, based on their cheliceral morphology and some limited laboratory observations (Walter 1987;Walter et al 1987;Walter and Ikonen 1989;Halliday et al 1998). Moreover, they can be reared on nematode diet exclusively (Walter 1987;Walter and Stirling 2018), and they are therefore considered potential biocontrol agents of soil-root pests (Walter 2003). The eurybiontic Gamasellodes bicolor (Berlese, 1918) can dominate entire Mesostigmata assemblages in mixed forest habitats (Madej et al 2011).…”