BioControl (2004) 49, 47-62

Steen Magnussenn, Susanne Vogelgsang and Simon F. Shamoun (2004)
Non-linear mixed models for repeated data assessment of time and temperature effects on conidia production in the fungus Valdensinia heterodoxa
BioControl 49 (1), 47-62
Abstract: Valdensinia heterodoxa Peyr. has potential for application as a biological control agent of salal (Gaultheria shallon Pursh) in regenerating forests in the Pacific Northwest region of North America. Conidia production of two isolates of Valdensinia heterodoxa was examined at four temperature levels during a 12-day period. Conidia production was strongly influenced by both temperature (with an optimum between 16 and 19 °C) and time (peaked at day 9). Replicate (five) variance was highly heterogeneous and made a conventional approach to the statistical analyses unsuccessful. However, newly developed generalized nonlinear models succeeded in identifying significant differences between isolates in their temperature specificity. One model was based on a time-dependent Poisson process (logistic model) modified by an independent nonlinear temperature function (a scaled gamma function). The other was a nonlinear growth model with fixed (time, isolate) and random (replicate) effects. We believe that nonlinear mixed models offer an attractive framework for analysis of longitudinal count data common in growth and reproduction studies.
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Link to article at publishers website
Database assignments for author(s): Steen Magnussenn, Susanne Vogelgsang, Simon Francis Shamoun

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution
rearing/culturing/mass production

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Gaultheria shallon (weed)
Valdensia heterodoxa (weed pathogen)	Gaultheria shallon (weed)