Canadian Journal of Botany - Revue Canadienne de Botanique (1999) 77, 537-547

Carol L. Ecale Zhou and Elaine A. Backus (1999)
Phloem injury and repair following potato leafhopper feeding on alfalfa stems
Canadian Journal of Botany - Revue Canadienne de Botanique 77 (4), 537-547
Abstract: We examined phloem injury and repair over an 8-day period following probing (feeding with piercing-sucking mouthparts inserted in plant) by the potato leafhopper, Empoasca fabae (Harris) (Homoptera: Cicadellidae), in stems of alfalfa, Medicago sativa L. A videomicrography technique was used to apply standard-duration probing by potato leafhoppers on alfalfa stems. Leafhopper-induced plant responses, observed using transmission electron microscopy and fluorescence microscopy, included phloem cell wall loosening and collapse, increased cytoplasmic density and dissolution of necrotic phloem cells, enlargement of nuclei and nucleoli in surviving cells, increased mitotic activity, thickening of phloem cell walls, formation of short and irregularly shaped wound sieve elements (often with side-wall sieve plates), accelerated chloroplast maturation and formation of abnormally large starch grains, and generation of phloem transfer cells from companion cells. Aniline blue staining of callose in sieve elements revealed that wound sieve tubes circumvented damaged phloem by 8 days after leafhopper-induced injury. These new sieve tubes often developed in the interfascicular area adjacent to the wounded bundles.
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Link to article at publishers website
Database assignments for author(s): Elaine A. Backus

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
damage/losses/economics

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Empoasca fabae	Alfalfa/lucerne (Medicago sativa)