Soil insects alter fine root demography in peach (Prunus persica)

Authors

  • C. E. Wells,

    1. Intercollege Graduate Program in Plant Physiology, The Pennsylvania State University, University Park, PA 16802, USA,
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    • *

      Present address: Department of Horticulture, 179 Poole Agricultural Center, Clemson University, Clemson, SC 29634, USA

  • D. M. Glenn,

    1. USDA–ARS Appalachian Fruit Research Station, Kearneysville, West Virginia 25430, USA and
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  • D. M. Eissenstat

    1. Department of Horticulture, The Pennsylvania State University, University Park, PA 16802, USA
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Correspondence: David M. Eissenstat. E-mail: dme9@psu.edu

Abstract

Minirhizotrons were used to assess the effects of soil insect suppression on the demography of peach fine roots (<1 mm diameter) over two growing seasons. The experiment was conducted at the USDA–ARS Appalachian Fruit Research Station in Kearneysville, WV, USA using six 15-year-old peach trees. Clear butyrate minirhizotrons were installed beneath each tree in April 1996. Soil drench treatments were applied around individual minirhizotron tubes at monthly intervals and consisted of 1 L of water or 250 µL of a broad-spectrum insecticide in 1 L of water. Roots were videotaped at 2- to 4-week intervals during the 1996 and 1997 growing seasons. Insecticide application was associated with a significant increase in fine root longevity: the median lifespans of insecticide-treated roots were 46–125 d longer than those of control roots. In addition, the development of brown pigmentation was significantly delayed in insecticide-treated roots. Insecticide application did not appear to increase soil fertility, as accumulation of NO3, NH4+, and PO42- on mixed bed ion-exchange resin was similar in treated and untreated soil. These results suggest that interactions with below-ground insects can significantly influence root longevity and may alter the rate at which roots undergo developmental changes in anatomy and physiology.

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