Effect of population densities of Meloidogyne enterolobiion growth of parsley (Petroselinum sativum L.) in pots

Abstract

The relationship between a geometric series of twelve initial population densities (Pi) of Meloidogyne enterolobii between 0 and 256 eggs and second stage juveniles (J2)/cm3 soil and growth of parsley (Petroselinum sativum L.) was investigated in clay pots containing 500 cm3 of sterilized sandy soil. Parsley seeds were planted, two plants per pot were left and inoculated with the nematode 15 days after germination. There were 10 replicates per inoculum level. Pots were maintained in a growth chamber at 26°C. Fresh and dry top weights were recorded at 45 days after inoculation. After aerial biomass was removed, plants were allowed to flush for an additional 35 days (80 days after inoculation). At that time, the fresh and dry weights of the new flushes were assessed and  cumulated  with  those  recorded  at  45  days  after  the  inoculation. At  this  date,  the  final  population  of  the nematode and gall index were also determined. The Seinhorst’s model y=m+ (1-m)zPi-Tgave an adequate fit to the relationship between average fresh and dry top weight of plants and nematode population density. Tolerance limits (T) to the nematode for fresh weight of parsley at 45 and cumulated weights at 80 (45 + 35) days was 0.1 eggs + J2/cm3 soil for both cases while the minimum relative yields (m) were 0.65 and 0.61 at Pi ≥16 and 8 eggs + J2/cm3 soil, respectively. Tolerance limits (T) to the nematode for dry weight of parsley at 45 days and cumulated weights at 80 (45 + 35) days were 0.3 and 0.1 eggs + J2/cm3 soil, and the minimum relative yields (m) were 0.6 and 0.43 at Pi ≥ 32 and 16 eggs + J2/cm3soil, respectively. Maximum nematode reproduction was 11.8-fold at Pi = 0.5 eggs and J2/cm3 soil. The highest final population density (Pf) of the nematode was 222 eggs and J2/cm3 soil and occurred at Pi = 256 eggs and J2/cm3 soil. The findings of this pot experiment provide evidence of the potential damaging effect that M. enterolobiimay cause to parsley under field conditions.