Damage Functions for Meloidogyne arenaria on Peanut.

Area of Science:

• Agricultural Science
• Plant Pathology
• Nematology

Background:

• Peanut (Arachis hypogaea) is susceptible to root-knot nematodes.
• Meloidogyne arenaria race 1 can cause significant crop losses.
• Understanding the relationship between nematode density and crop yield is crucial for management.

Purpose of the Study:

• To determine the relationship between peanut yield and Meloidogyne arenaria race 1 inoculum density.
• To quantify yield losses at various initial nematode population levels.
• To establish a tolerance limit for M. arenaria in peanut cultivation.

Main Methods:

• Microplot experiments were conducted over two growing seasons (1989, 1990).
• Nine inoculum densities of M. arenaria (0-200 eggs/100 cm³ soil) were tested with 10 replicates.
• Peanut pod yield and foliage dry weight were measured at harvest.

Main Results:

• Pod yield and foliage dry weight were negatively correlated with initial M. arenaria inoculum density (P ≤ 0.05) in both years.
• Seinhorst's equation described the yield-density relationship, with R² values of 0.826 (1989) and 0.794 (1990).
• Final nematode densities varied, with higher levels observed at lower initial inocula in 1989.

Conclusions:

• Peanut yield is significantly reduced by M. arenaria race 1, even at low initial densities.
• The estimated tolerance limit for M. arenaria in peanuts is approximately 1 egg/100 cm³ soil.
• Accurate detection of low nematode populations, potentially via bioassay, is necessary for effective management.