TABLE CONTENTS

• Onion plant stand negatively correlated with length of barley cover crop growth, but
nullified by 14 days of fallow.
• Carry-over effects in a second season, with reduced plant stand and yields in ‘stunted
patch’ soil previously cropped to barley.
• Lowest root rot severity in ‘non-patch’ soil not cropped to barley.
• Reduced emergence and growth associated with barley cover crops or addition of pea
straw.
• Possible toxic effects from pea straw decomposition, with reduced yields at rates of 2
t /ha or higher.
• Growth stimulation in the following season in soil previously amended with pea
straw.
• Possible allelopathic effects from a wheat nurse crop, grown for five weeks, inhibiting
emergence of onions.
• Accelerated rate of damping-off in quintozene-treated soil, implicating pathogens
other than R. solani
• Stimulated root growth in the following season in soil previously treated with
quintozene.
• Reduced emergence associated with N fertilizer, deeper (20 mm) seed placement, or
cooler, ambient temperatures.
• Increased emergence and growth, and reduced Pratylenchus population, in onions
grown in soil treated with fenamiphos or lucerne pellets.
• Inhibited emergence in fenamiphos-treated soil in the following season, possibly
caused by carry-over effects on beneficial organisms.
Soil Amendments and Natural Products forNematode Management in
California
Westerdahl, B.B. (1), J.D. Radewald (2) & J. Nunez (3)
(1) Department of Nematology, University of California, Davis, CA 95616; (2) Department of Nematology,
University of California, Riverside, CA 92651; (3) University of California Cooperative Extension, Bakersfield,
CA 93307.
In two years of field trials on carrots, natural products were tested alone, and in combination,
and compared to untreated controls and a chemical standard for management of root-knot
nematode (Meloidogyne javanica). Each trial consisted of five replicates in a randomized
complete block design. Several of the treatments reduced nematode populations or improved
yields.
5 th International Congress of Nematology, 2008 289