Phytoparasitica (2000) 28, 55-64

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M.A.B. Morandi, J.C. Sutton and L.A. Maffia (2000)
Relationships of aphid and mite infestations to control of Botrytis cinerea by Clonostachys rosea in rose (Rosa hybrida) leaves
Phytoparasitica 28 (1), 55-64
Abstract: Infestations of aphids (Macrosiphum rosae L.) and of twospotted spider mites (Tetranychus urticae Koch) were examined in relation to growth and sporulation of Clonostachys rosea and Botrytis cinerea, and to suppression of the pathogen by the agent, in green rose leaves. Leaves were infested artificially with 10 aphids/leaflet for 3 h, or naturally with 15–30 aphids/leaflet for 7–12 days or with undetermined numbers of mites for 10–12 days. Leaves that had or had not been infested were inoculated with C. rosea, with B. cinerea, or with C. rosea plus B. cinerea. Germination incidence and germ tube growth of C. rosea and B. cinerea on the phylloplane in most instances were much greater in leaves previously infested with aphids or mites compared with noninfested leaves. After combined inoculation, C. rosea suppressed germination of B. cinerea from 47% to 19% in noninfested leaves, but in leaves that had been infested the agent was ineffective and germination incidence of the pathogen increased to 75–93%. Previous infestation with naturally introduced aphids or mites, but not brief infestations of artificially introduced aphids, markedly increased sporulation of C. rosea after the leaves died during an initial 7–15 days of incubation on a paraquat agar medium, regardless of whether or not B. cinerea was present. Sporulation of B. cinerea was similarly increased when inoculated alone. After 15–20 days, however, conidiophores of the agent or pathogen covered most of the leaf surface in these treatments. In leaves inoculated with C. rosea plus B. cinerea, the agent suppressed sporulation of the pathogen almost completely in both previously infested and noninfested leaves. Thus, aphid and mite infestations did not compromise the ability of C. rosea to suppress inoculum production by B. cinerea in the leaves. Increased nutrient availability on the phylloplane through exudation or as honeydew or frass is proposed as a basis to explain effects of the pest infestations on C. rosea and B. cinerea.
(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): Marcelo A.B. Morandi, Luiz A. Maffia

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Tetranychus urticae Rosa (crop)
Botrytis cinerea Rosa (crop)
Macrosiphum rosae Rosa (crop)
Clonostachys rosea (antagonist) Botrytis cinerea Rosa (crop)