Host Tests to Differentiate Meloidogyne chitwoodi Races 1 and 2 and M. hapla

Area of Science:

• Plant Nematology
• Agricultural Entomology
• Crop Science

Background:

• Root-knot nematodes, including Meloidogyne chitwoodi, pose significant threats to agriculture.
• Meloidogyne chitwoodi has distinct races with varying host specificities.
• Accurate identification of nematode species and races is crucial for effective pest management.

Purpose of the Study:

• To compare the reproductive efficiency of Meloidogyne chitwoodi race 1 and race 2 on various crop cultivars.
• To identify differential hosts that distinguish between Meloidogyne chitwoodi races.
• To propose a new differential host test for common Pacific Northwest root-knot nematode species.

Main Methods:

• Assessing the reproductive factor (R) of Meloidogyne chitwoodi race 2 on 46 crop cultivars.
• Comparing the reproductive efficiency of Meloidogyne chitwoodi race 1 and race 2 on selected cultivars, focusing on alfalfa and carrot.
• Evaluating host responses to Meloidogyne chitwoodi races and Meloidogyne hapla.

Main Results:

• The reproductive factor (R) for Meloidogyne chitwoodi race 2 on 46 cultivars ranged from 0 to 130.
• Meloidogyne chitwoodi race 2 reproduced effectively on alfalfa but not on carrot.
• Meloidogyne chitwoodi race 1 showed poor reproduction on alfalfa but suitable reproduction on carrot.

Conclusions:

• Differential host reproduction on alfalfa and carrot distinguishes Meloidogyne chitwoodi race 1 and race 2.
• A novel differential host test utilizing host responses to Meloidogyne chitwoodi races and Meloidogyne hapla is proposed.
• This test can aid in distinguishing common root-knot nematode species in the Pacific Northwest.