An ecofriendly Root- Knot Nematode Pest Management Strategy on Sugarbeet 1- Utilizing Microbial Agents

Abstract

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.

Silicon promotes the control of Meloidogyne incognita in lettuce by increasing ascorbic acid and phenolic compounds

“…It should be noted that the relationships of these compounds with nematicidal action were veri ed only in synthesized products. Therefore, there are reports of exogenous phenolic compounds increasing the mortality of second stage juveniles and decreasing the number of galls of M. incognita in tomato (Oliveira et al 2019), and reports of the use of AsA in tomato (Osman 1993) and beet (Maareg et al, 2014). These compounds play an important role in the host-parasite interaction (Arrigoni 1979).…”

“…This hypothesis is promising due to two reasons. Firstly, research indicates that the isolated application of phenolic compounds (Oliveira et al 2019) and synthesized ascorbic acid (Osman, 1993;Maareg et al, 2014) has a toxic effect and decreases the population of nematodes in the plant.…”