Soil Temperature Effects on Onion Seedling Injury by Pratylenchus penetrans

Area of Science:

• Plant Pathology
• Nematology
• Agricultural Science

Background:

• Pratylenchus penetrans is a significant plant-parasitic nematode.
• Onion (Allium cepa) is susceptible to nematode damage.
• Soil temperature is a critical environmental factor influencing nematode activity and plant response.

Purpose of the Study:

• To determine the effect of varying soil temperatures on onion seedling injury caused by Pratylenchus penetrans.
• To establish temperature-dependent nematode population thresholds for onion root damage.

Main Methods:

• Seedling onions were exposed to controlled soil temperatures ranging from 7-25 C.
• Inoculation with Pratylenchus penetrans at different densities.
• Assessment of onion root weights and nematode populations at five weeks.

Main Results:

• At cooler soil temperatures (7-13 C), fewer than 100 nematodes per gram of root significantly reduced onion root weights.
• At warmer soil temperatures (16-25 C), over 400 nematodes per gram of root were needed to cause comparable injury.
• A clear inverse relationship between soil temperature and nematode pathogenicity was observed.

Conclusions:

• Soil temperature is a key factor modulating the pathogenicity of Pratylenchus penetrans to onion seedlings.
• Lower soil temperatures increase the susceptibility of onions to nematode damage.
• Management strategies for Pratylenchus penetrans in onions should consider soil temperature variations.