This is in continuation to my earlier post on Diseases of apple: Collar rot Description. This disease is generally diagnosed wrongly for white root rot and we treat it for the same by drenching with carbendazim, that further worsen the situation and plant dies pre-maturely. If diagnosed with the symptoms explained in my previous post i.e. coffee brown colour and late bud break, more number of spurs, small and sparse leaves, it should be managed in holistic way
- Phytosanitation: Free
water or flood irrigation high moisture content near the
trunk are major pre-disposing factors for the disease to spread. So keep
the cultivation area free of diseased material like diseased bark and
roots, etc. The cleanliness reduces the primary inoculum of the disease
causing agents. This simple principle should be followed as soon as the
first symptom in the form of late bud break or purple veins appears on lower
side of leaves. This is the best way to manage the diseases on small farms
and helps in reducing the costs.
Practices: Alter the environment in which disease is
appearing i.e. high moisture level in the basin and nearby trunk. Add
gravels and sand near the trunk, remove soil from graft union. Improve drainage
from the basin area. Since this also removes the primary inoculum as well
as modifies the environment for disease proliferation again without
enhancing the cost to a greater level.
Control: Introduction of biological control agents in
the soil e.g. Trichoderma viride, and its variants help the plant
in fighting with plant pathogen and grow healthy with a little cost.
If consortium of different soil inhabiting biocontrol agents is available it
will help better in managing the disease.
Control: Agrochemicals should be the last priority to
manage the disease and that too after the proper diagnosis. As the
application of a wrong chemical will not only worsen the situation but
also pollute the soil and soil microflora. i.e. soil health. In
turn increase the cost without preventing the damage caused by the
insect-pests or disease. Different combiproducts have been reported
to control the disease among these, combinations of metalaxyl + mancozeb,
moxymate + mancozeb, and dimethomorph are very effective.
In my comng post I shall be discussing about white root rot of apple.