Tomato Cultivation updates and News.

Tomato Cultivation: Tomato Crop Protection

Tomato crop protection consist of disease management of tomatoes.

Late blight:

The disease appeared on the foliage at any stage of growth.

Brown to purple black lesions began at any point on the leaflet, rachis, petiole or stem and advanced rapidly to cause a severe blight when conditions were favourable.

Lesion growth was checked with low humidity.

When lesion advanced to outermost zone it was pale yellow. On lower side of leaves, the white fructification of the fungus appeared where the pale and purple areas joined.

In fruits, symptoms were mostly at stem end. Grey water soaked spots enlarged to indefinite size and shape.

Fungicide sprays of Dithane Z-78 and partate were effective for controlling the disease.

Other fungicides found effective were Dithane M-45, Difolatan, daconil 2787 and metalaxyl.

Early blight:

The early blight, one of the most common foliage blights of tomato was caused by Alternaria solani.

The pathogen was first recorded in 1882 in New Jersey.

Disease appeared first as spots on leaflets.

They were circular to angular dark brown to black and ranged from pin head to 4 mm in diameter in size.

Concentric ridges often formed leathery necrotic tissues.

High soil fertility tended to reduce the severity of the infection.

Damping off and root rot:

These diseases are caused by Pythium spp., Rhizoctonia solani, Phytopthora parasitica and a few other organisms.

These are very serious diseases affecting plants at the nursery stage.

Control measures consisted of soil treatment with formaldehyde 2 weeks before sowing and seed treatment with 1% mercuric chloride.

Spraying of seedlings with fytolan or captan was effective.

Hot water seed treatment at 52˚C for 30 minutes was recommended along with 5 year crop rotation.

Epilachna beetles (Epilachna vigintioctopunctata):

Both larvae and adult feed on the leaves.

Feeding is irregular and gives the plant a characteristic lace-like appearance.

Spraying of endosulfan or dichlorophos or chlorophyriphos at 0.1% controls this pest.

White fly (Bemesia tabaci):

They are minute white insects and suck the sap of the plants.

It acts as vector for transmitting leaf curl disease.

Control measures have already been discussed in leaf curl virus disease.

Chemical control of white fly included spraying of different pesticides and pyrethroids.

Spraying (with pyrethroids) and cooling of greenhouse resulted in reduction of population of white fly.