The effects of photoperiod and light intensity on the sporulation of Brazilian and Norwegian isolates of Neozygites floridana

Author(s)

de Castro, Thiago Rodrigues ^[1] ; Wekesa, Vitalis Wafula ^{[2, 3]} ; Moral, Rafael de Andrade ^[4] ; Borges Demetrio, Clarice Garcia ^[4] ; Delalibera, Jr., Italo ^[1] ; Klingen, Ingeborg ^[2]

Affiliation

^[1] ESALQ Univ Sao Paulo, Dept Entomol & Acarol, BR-13418900 Piracicaba, SP - Brazil

^[2] Norwegian Inst Agr & Environm Res Bioforsk, Plant Hlth & Plant Protect Div, Dept Entomol & Nematol, N-1432 As - Norway

^[3] Tech Univ Kenya, Nairobi - Kenya

^[4] ESALQ Univ Sao Paulo, Dept Exact Sci, BR-13418900 Piracicaba, SP - Brazil

• Document type: Journal article
• Source: Journal of Invertebrate Pathology; v. 114, n. 3, p. 230-233, NOV 2013.
• Web of Science Citations: 4

Abstract

The objective of this study was to determine the effects of light intensity and duration (photoperiod) on the sporulation (discharge of primary conidia) and conidia germination (from non-infective primary conidia to infective capilliconidia) of Neozygites floridana isolates from Tetranychus urticae originating from Norway and Brazil. Two light intensities (40 and 208 mu mol m(-2) s(-1)), three photoperiods (24 h of continuous light (24 h D), 12 h of darkness followed by 12 h of light (12 h D:12 h L) and 24 h of continuous darkness (24 h D)) and two temperatures (18 degrees C and 23 degrees C) were tested. The fungus produced similar amounts of primary conidia and capilliconidia at 12 h D:12 h and 24 h D, indicating that the fungus discharges almost all of its conidia during the first 12 h of darkness. Light had less of an effect on the production of primary conidia than on capilliconidia formation. At 24 h L, capilliconidia formation was significantly lower for all tested light intensities, temperatures and isolates compared to 12 h D:12 h L and 24 h D. At both light intensities, 24 h L resulted in a significantly lower capilliconidia formation for the Norwegian isolate compared to the Brazilian isolate. Our data suggest that, even though 24 h L reduced sporulation, some capilliconidia formation may occur at the low light intensities found on the underside of strawberry leaves during parts of the day as well as the top of a non-shaded strawberry leaf during the dim evening and morning hours in the tropics and during the dim, long summer days in temperate regions. (C) 2013 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 08/07358-0 - Development of methodology for production in vivo and release of the fungus Neozygites for the control of Tetranychus urticae Koch mite.
• Grantee: Thiago Rodrigues de Castro
• Support Opportunities: Scholarships in Brazil - Master