Plant Doctor Archive

Carrots being attacked

THE foliage on my carrots is being eaten. I have them planted in an old water tank, which does not get at lot of sunshine. Could this be a reason they're being attacked?

CARROT rust fly could be the problem. The adult fly lays its eggs close to the young carrots and, on hatching, the larvae tunnel into the root, often causing the leaves to turn yellow and die off. The problem tends to be worse in carrots growing in shady, sheltered conditions and is difficult to control.

Don't plant carrots or related vegetables, like parsnips, celery and parsley, in that area again. Only grow them in an open, well-lit spot elsewhere in the garden. Leeks, onions and rosemary are said to have a repelling effect on carrot rust fly, so next time you sow carrots you could try intermingling them with onions or leeks. Finely woven netting laid over seedling carrots can also be helpful at preventing the adult fly from laying its eggs. The smell of fresh lawn clippings sprinkled along the rows close to the young carrots is also reported to disguise the smell of carrots and so prevent the adult fly laying eggs.

As a last resort you could apply Diazinon granules to the soil when you sow the carrot seeds, follow the label recommendations.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.