Agricultural and Forest Entomology (1999) 1, 111-117

R. Lilley, C.A.M. Campbell and M.S. Ridout (1999)
Vertical dispersal of the two-spotted spider mite Tetranychus urticae, and the predatory mite Phytoseiulus persimilis on dwarf hops
Agricultural and Forest Entomology 1 (2), 111-117
Abstract: 1 The pattern of dispersion within plants of the two-spotted spider mite, Tetranychus urticae, and its predator, the phytoseiid Phytoseiulus persimilis, was studied on the dwarf hop variety First Gold from May to September in 1997 and 1998.
2 Spider mite populations developed on the lower leaves initially but, by late July, as the numbers of mites increased, most were found towards the top of plants. From early August, the numbers of spider mites decreased most rapidly on the upper parts of plants.
3 Where P. persimilis was released, the predator maintained the numbers of T. urticae below those found on non-release plots throughout the season.
4 By early August, the predator's pattern of dispersion was similar to that of the pest.
5 Predators spread to non-release plots by 20 June in 1997 and 24 July in 1998 and eventually became more numerous than on the plots where they had been released.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Colin A.M. Campbell

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
population dynamics/ epidemiology
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation
application technology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tetranychus urticae	Hop (Humulus lupulus)	United Kingdom
Phytoseiulus persimilis (predator)	Tetranychus urticae	Hop (Humulus lupulus)	United Kingdom