Filtrates of several fungi (Arthrobotry oligospora, Dactylella brochopage,
Nematochomus concurrence, Fusarium exsporium, Trichoderma harzianum and
Varticillium chlamydosporium) and bacteria (Bacills cereus, B. thuringiensis,
Psendornonas fluorescens and Serratia odorifera) as biocontrol agents were tested
for their nematicidal against the root-knot nematode, M. javanica infecting sugarbeet
plants, as well as for their effects on yield and quality parameters. These microbial
filtrates were applied as soil drench at the three concentrates (50, 75 and 1000%).
Results showed that all fungi and bacteria filtrates significantly reduced the
numbers of nematode population and reproduction factor comparing to the check
treatment. The reduction percentage of nematode counts and reproduction factor
was affected by microbial filtrate type and concentration used. Enhanced reduction
followed increased concentration in each microbial filtrate. Moreover, root, leaves
and sugar yields, as well as quality characters (i.e. T.S.S., sucrose and purity %)
were also significantly increased.
Among the fungi filtrates, V. chamydosporiusm filtrate at the highest
concentration recorded the maximum effect in reducing number of nematode
population and reproduction factor. Also, the highest increase percentages of
leaves, root, sugar yields and sucrose, T.S.S and purity% were obtained at the
highest concentrations of V. chlamydosporium. In case bacteria filtrates, the highest
reduction of nematode population and reproduction factor as well as, the greatest
root and sugar yields increases were achieved at the highest concentration of B.
cereus and S. odorifera, filtrates.
Generally, the plants treated with V. chlamydosporium, B. cereus and S.
odorifera filtrates had less nematode population and higher productivity of sugarbeet
than those plants treated with the other tested microbial agents. In addition,
these filtrates had nearly the same effect of the nematicide, Oxamyl on root-knot
nematode, M. javanica. Also, these biocontrol agents are ecological sound,
economical viable and partial substitutes for costly and pollution causing chemical
nematicides and have been a successful instead of these chemical nematicides
management strategy when used alone or in combination with other strategies.