Diseases and Management of Crops under Protected Cultivation

(Diseases and Management of Crops under Protected Cultivation)
Roll out Pinching: It is used only on short plant or soon after cutting are planted.
2. Disbudding: It is done to remove the side branches, which arise from axillary buds. Number of
flower is limited and bloom of better size is obtained. In standard chrysanthemums, regular
disbudding is done to obtain a single large bloom.
3. Staking: Staking is necessary to provide the support & maintain proper shape of plants &
blooms. There are only a few varieties which neither require pinching nor staking and hence
known as ‘no stake no pinch’ varieties. In standard type, number of stakes is dependent on the
number of main branches and in spray type, 3-4 stakes are inserted.
Growth regulation: Growth regulation can be done by controlling the environment as well as by
use of plant growth regulators. Long day conditions result in extended vegetative growth and
induction of short days result in flower bud initiation.
GA 3 50 ppm spray at 30, 45 and 60 th day after planting increases the total flower yield.
Number of quality flowers can be increased by spraying triacontanol (100 mg/l). Ascorbic acid
spray at 1,000 ppm either on 35 th day or 70 th day after transplanting significantly increased the
overall growth rate. B-nine (5,000 ppm) spray resulted in highest number of flowers per plant.
Plant Protection
Diseases
1) Root rot (Pythium spp or Phytophthora spp.): In this disease, the infected plant suddenly wilt
the plant parts like roots, stems, leaves.
Control measures
i) Provide good drainage conditions to prevent water logging.
ii) Soil drench with thiram or captan or mixture of both at the rate of 2.5 g/m 2 area prevents
the infection.
iii) Mancozeb, Metalaxyl and Fosetyl- also used for control.
2) Leaf spot (Septoria chrysanthemella): Greyish brown spots appear on leaves which turn
yellow surroundings. When flowering starts, the infection occurs on flower buds, which rot
completely. The disease spreads from down to upwards.
Control measures
i) Spraying with mancozeb at fortnightly interval helps in controlling the disease.
ii) Burning and destroying of infected leaves.
iii) Spray of Copper oxychloride (0.2%).
3) Wilt (Verticillium dahliae): The leaves turn yellow to grey and the branch or whole plant wilts
gradually. It may occur due to a number of diseases, disorders or even just lack of water.
Control measures
i) Solarization of soil by using black polythene mulch during summer months.
ii) Soil treatment with Dithane M-45 (0.2%)
iii) Dipping of rooted cuttings in Benomyl suspension before planting.
- 209 -