Population changes of Heterodera glycines eggs on soybean in small field plots were influenced by the lepidopterous insect pest, Helicoverpa zea; however, few effects on eggs due to the presence of annual weeds were detected. Soybeans defoliated 15-35% by H. zea during August remained green and continued to produce new flowers and pods later into the season than soybeans without H. zea, resulti...

In May 2007, a widespread frost event defoliated much of Utah's high elevation aspen. About 5 weeks later, the frost-defoliated aspen produced a second leaf flush. The objective of this study was to characterize changes in leaf morphology and function in re-flush leaves following frost defoliation. Leaf size and thickness, photosynthesis, carbohydrate and nutrient status, and defense chemistry ...

At the end of the growing season in late July, 20-month-old cork oak (Quercus suber L.) saplings were partially defoliated (63% of leaf area) to evaluate their ability to recover leaf area after defoliation. At 18 and 127 days after defoliation, changes in starch and nitrogen pools were determined in leaves and perennial organs, and variations in photosynthetic carbon uptake were investigated. ...

Late-summer starch accumulation in fine roots of poplars (Populus x canadensis Moench.) defoliated by gypsy moth (Lymantria dispar L.) lagged behind that in fine roots of undefoliated trees. If starch concentration declines with age, defoliation-induced changes in root system age structure could be partly responsible for this difference. To test this hypothesis, we measured fine-root starch and...

Understanding the ability of koalas to respond to changes in their environment is critical for conservation of the species and their habitat. We monitored the behavioural response of koalas to declining food resources in manna gum (Eucalyptus viminalis) woodland at Cape Otway, Victoria, Australia, from September 2011 to November 2013. Over this period, koala population density increased from 10...

Climate extremes such as cold spells are becoming more frequent climate variability increases. However, few studies have evaluated the impacts of winter on forest cover, tree growth and leaf sapwood non-structural carbohydrate (NSC) concentrations. We analyzed changes in cover using remote sensing data compared radial coexisting defoliated Pinus halepensis trees non-defoliated P. pinaster trees...

Although Polychronopolis and Lownsbery (1) found that Heterodera schachtii invaded the radicle, hypocotyl, and cotyledons of seedling sugarbeet, they observed no histological or cytological changes other than cellular death and disorganization. Ross (2) reported development of females and brown cysts accompanied by formation of giant cells and hypertrophy in leaves of white clover inoculated wi...

Defoliation of alfalfa (Medicago sativa L.) results in a cyclic pattern of starch degradation followed by reaccumulation in taproots. Characterization of changes in anatomical distribution of starch grains in taproots will aid our understanding of biochemical and physiological mechanisms involved in starch metabolism in taproots of this species. Our objectives were to determine the influence of...