TABLE CONTENTS

test indicate some isolates reduce R. reniformis in greenhouse conditions. Fatty acid prints
have been identified for R. reniformis and M. incognita. Eleven fatty acids have been found
to be significant to distinguishing among R. reniformis from M. incognita. Six of these fatty
acids are observed in a much greater concentration in R. reniformis than M. incognita. These
results indicate that R. reniformis and M. incognita can be demarcated by FAME analysis.
Reniform Nematode and Cotton Production in the USA
Overstreet, C. & E.C. McGawley
Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton
Rouge, Louisiana, USA
During the past two decades, reniform nematode (Rotylenchulus reniformis) has emerged as a
major pest problem in upland cotton, Gossypium hirsutum L., in the mid-South and Southeast
regions of the USA Losses from this pest have been estimated at over one billion (U.S.
dollars) during the past 10 years. There is clear evidence that this nematode is still spreading
and has certainly increased in the both incidence and severity in a number of states. Although
a number of other crops are susceptible, incidence and severity appears to be greatest on
cotton. Yield losses from this nematode have been reported as high as 60% in some fields but
typically average between 10-20%. Currently, there are not any cultivars of upland cotton
that are planted the USA that have any level of resistance against this nematode. The primary
methods that are utilized to manage this pest are crop rotation and nematicides. Corn is the
most widely planted rotational crop for managing reniform in the mid-South with the addition
of peanuts in the Southeast. The predominate nematicide until recently was aldicarb. Seed
treatment nematicides including abamectin and thiodicarb have recently seen increased use
during the past several years. An older fumigant, 1,3-Dichloropropene, has seen increased
usage during the past several years particularly in the area of site-specific nematicide
application. This technology is now being extensively evaluated for use against the reniform
nematode in cotton in both regions of the USA Fields can be delineated into management
zones based on soil texture utilizing apparent soil electrical conductivity (EC a ), population
densities of reniform nematode, aerial imagery collected during the cropping cycle, or simply
where the crop responds to nematicide application. Reniform nematode remains a serious
threat to the cotton industry in the USA
5 th International Congress of Nematology, 2008 183