Don’s Expert Answers: Nematodes affecting root veges

Question From: 
Rod Yates in  Arcadia,  arcadia  NSW

 

Nature of problem: 
Nematodes affecting root veges

 

Type of Plant (if known): 
Carrots Parsnips, beetroot

 

Symptoms of Plant Illness (please try NOT to diagnose your problems yourself): 
irregular form, lumpy shapes,divided roots

 

Soil Type (e.g. sandy, clay or loam) OR Potting Mix Type: 
Garden loam bought from Martins soils at Round Corner.

 

How often do you water the plant:
Only rainfall

 

How many hours of sunlight does the plant get each day:
full day

 

What type of plant is it:
carrots and parsnips

 

How long since you planted it:
three months

 

Have you fertilised? If so, with what and when:
no

 

Is the plant indoors or outdoors: 
outdoors

 

Is the plant in a pot or in the ground: 
ground

 

What other treatments have you given the plant: 
none

Upload photo if available: 

Other Comments: 

I am surprised that there are no simple answers for treating nematodes on Google, unless you can take a season to grow marigolds, or use ethyl bromide and polyethelene sheeting
I have heard you can use sugar or mollasses, but for some reason that also damages the soil.
Can you give me any other ideas please.
A lady at Bunnings said you might be able to suggest something.

 

Answer: Hi Rod,  Above we ask People “not to Not to diagnose your problems yourself”. From your symptoms it sounds like you might have nematodes but it is equally likely that you have a fungal infection – which reinforces our stance re asking people not to give us diagnoses, just symptoms.. It could be a fungal root disease called Pythium sulcatum which commonly causes forking etc on carrots & related root crops (previously old husbands’ tales blamed this on hard, rocky soil).  Crop rotation with onions, potatoes, beans and cereals will help to fend the disease off from one year to the next. Some experts claim that too much fresh compost in the soil also favours pythium infection. Keep the pH around 6.5-7 and do not let it get acid ( ie below 6.5). I simply don’t have enough info to make a better diagnosis. A photo would have helped.  My only aim is to try to help you.  Don