Experimental and Applied Acarology (2014) 62, 337-362

Sara Pascual-Ruiz, Ernestina Aguilar-Fenollosa, Victoria Ibáñez-Gual, Mónica A. Hurtado-Ruiz, M. Teresa Martínez-Ferrer and Josep A. Jacas (2014)
Economic threshold for Tetranychus urticae (Acari: Tetranychidae) in clementine mandarins Citrus clementina
Experimental and Applied Acarology 62 (3), 337-362
Abstract: Tetranychus urticae is a key pest of citrus in Spain, especially of clementine mandarin trees. The effects of this mite on fruit production were assessed in 24 clementine trees for three consecutive years. Trees were visited weekly and spider mite and phytoseiid mite populations and leaf flush patterns were estimated. At the end of the season, mandarins were harvested, weighed, and mite damage (scarring on the fruit) characterized. Negative relationships between spider mite density and yield (kg/tree) and fruit damage (% scarred fruit rind) were found. The multivariate regressions highlighted the key role of phytoseiid mites and leaf flush patterns, which were negatively related to fruit damage. The shortest sampling period that satisfactorily predicted fruit damage at harvest, extended from August to mid-October. For IPM purposes, an action threshold of 31.1 mites m^-2 of symptomatic leaf was estimated. Taking into account spider mite dynamics, the economic threshold ranged from 10 to 15 mites m^-2 of symptomatic leaf. When this threshold is exceeded growers would have a 1-week window to apply the control technologies against T. urticae of their choice.
(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): Josep-Anton Jacas Miret, Ernestina Aguilar-Fenollosa, Maria Teresa Martinez-Ferrer

Research topic(s) for pests/diseases/weeds:
thresholds/decision-support systems
damage/losses/economics

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tetranychus urticae	Citrus (genus)	Spain (continental)