Abundance and natural control of the woolly aphid Eriosoma lanigerum in an Australian apple orchard IPM program

Abstract

Woolly aphid (Eriosoma lanigerum Hausmann) (Hemiptera: Aphididae), was monitored over three growing seasons (1995)(1996)(1997)(1998) to assess its abundance and management under apple IPM programs at Bathurst on the Central Tablelands of NSW, Australia. Woolly aphid infestations were found to be extremely low in IPM programs utilising mating disruption and fenoxycarb for codling moth Cydia pomonella L. (Lepidoptera: Tortricidae) control. This was the direct result of increased numbers of natural enemies. No insecticides were applied for woolly aphid control. Under the IPM strategies tested the principal control agent was identified as European earwig (Forficula auricularia L.) (Dermaptera: Forficulidae). Earwigs in combination with Aphelinus mali (Haldeman) (Hymenoptera: Aphelinidae) reduced woolly aphid infestations below the action threshold set by commercial growers. However, A. mali together with other flying natural enemies, e.g., ladybirds, lacewings and hoverflies, did not provide commercially acceptable control of woolly aphid in the absence of earwigs. Under the conventional spray program, using the broad-spectrum insecticide azinphos-methyl for codling moth control, the level of woolly aphid infestation increased with each successive season and biological control was not established. When azinphos-methyl was withdrawn, natural enemies migrated in and provided control of woolly aphid within one season. This is the first study to show that the biological control of woolly aphid can be achieved in a commercially viable IPM program.

Effects of the concurrent exclusion of ants and earwigs on aphid abundance in an organic citrus grove

“…However, the exclusion of earwigs can certainly have an effect. Earwigs are known to consume aphids (Carroll and Hoyt 1984;Blommers 1994;Solomon et al 2000;Nicholas et al 2005) and we confirmed the presence of aphids in their diet in this particular grove (Fig. 3).…”

“…4d, 5d). A similar negative relationship between aphid and earwig densities was recently described in an apple orchard in Australia (Nicholas et al 2005). A negative relationship between predator and prey abundance suggests a topdown control of prey by predators (McQueen et al 1989;Worm and Myers 2003).…”

Ecological and life-history notes on syrphid predators of woolly apple aphid in Virginia, with emphasis on Heringia calcarata

“…However, unlike the Washington study, hover fly larvae appeared to be the dominant predators in Virginia, concurring with earlier observations by Brown and Schmitt (1990) and Bergh and Louque (2000). While earwigs have been shown to control woolly apple aphid populations in Australia (Nicholas et al 2005) and Holland (Mueller et al 1988), they have not been considered a significant predator of any apple pest in the Mid-Atlantic region of the United States and it is likely that the predator complex and their relative impacts vary considerably among geographic locations.…”

“…The importance of predation on E. lanigerum early in the apple growing season has long been recognized (Dumbleton and Jeffreys 1938;Bodenheimer 1947) and several studies have concluded that predators exerted more impact on woolly apple aphid than A. mali (Holdsworth 1970;Gruys 1982;Walker 1985;Nicholas et al 2005). However in general, the role of predators in reducing woolly apple aphid population density is not well understood (Asante 1997;Mols and Boers 2001) and merits further investigation.…”

Phenotypic and Molecular Screening of Apple Genotypes to Woolly Apple Aphid Resistance

“…Therefore, adopting biological control through the introduction of the natural endoparasitoid Aphelinus mali is a good choice (Brown and Schmitt, 1994;Asante, 1997). However, its susceptibility to many of the insecticides and fungicides commonly used in apple orchards limits its use (Cohen et al, 1996, Nicholas et al, 2005Rogers et al, 2011). Cultural control still offers a valuable mean to control WAA in apple orchards through the use of host-plant-resistance (HPR) strategy (Webster, 2003).…”