The Relationship Between Tobacco Yield and Time of Infection with Meloidogyne javanica

Yield of tobacco was related to the amount of infection by Meloidogyne javanica during the first month after transplanting. Six nematicidal treatments significantly reduced infection during this period and subsequently increased yield. However, during the second month after transplanting, infection in plots treated with O-ethyl S,S-dipropyl phosphorodithioate (V-C 9-104) and a mixture of 80% chlorinated C hydrocarbons + 20% methyl isothioeyanate (DD + MENCS) was not significantly different from infection in untreated plots. After 3 months, root-knot indices in plots treated with V-C 9-104, DD + MENCS, O,O-diethyl O-[p-(methylsulfinyl) phenyl] phosphorothioate (B-25141), and 1,3-dichloropropene, 1,2-dichloropropane (DD) were not significantly different from those in untreated plots; reduced infection was present only in plots treated with ethylene dibromide (EDB) and 2-methyl-2 (methylthio) propionaldehyde O-(methylcarbamoyl) oxime (aldicarb). At the end of harvest (4 months after transplanting), root-knot indices in all plots were essentially equal.