The nursery beds are to be kept free of weeds. Mulching is an important operation to be undertaken in seedling nurseries before the beginning of summer. Natural materials like tree lopping, dry leaves, undergrowth from forests, grass cuttings, cut cover crop material after drying are commonly used for mulching. Mulching helps to retain soil moisture. For irrigating large nurseries, sprinkler system would be ideal, whereas manual watering is convenient and cheap for small nurseries. The quantity of water required varies with soil, climate and age of plants. In general, nurseries are to be irrigated at an interval of 2 to 3 days.
This is the ideal time to raise rubber plants in polybags. Plants raised in polybags for six to seven months when planted in the field are expected to become tappable about one year earlier. Selection of plants with uniform growth for field planting is possible when polybag plants are used. The reduction in immaturity period proportionately reduces the expenditure during this phase. Black-coloured polybags are better as they ensure a better growth and development of roots. Sufficient holes if punched in the bottom half of the polybags will ensure proper drainage. Rock phosphate (50g) should be mixed in the top 20 cm soil in the polybag just before planting the budded stumps. Planted stumps should be irrigated in the evenings. Nurseries in open places should have overhead pandals to give protection to the sprouting stumps from hot sunlight.
Plants grown in nursery beds and polybags are affected by leaf spot and powdery mildew diseases. Application of 1% Bordeaux mixture or 0.2% Dithane M-45 / Indofil M-45 (2.66 g/L water) is recommended for control of the leaf spot diseases.
Chances of young polybag plants under irrigation and shade getting infected with powdery mildew are very high. Infected young leaves show white fungal myclial growth forming small to larger sports which appear like powder sticking on the leaves. Affected leaves gradually get dried up, curl and drop. This can be controlled by spraying wettable sulphur at the rate of 10 g in 4 litres of water once in 7-10 days. Applying Bavistin 1 g per litre of water can also control the disease. Alternative application of sulphur and Bavistin is more effective. Sulphur dust can also be applied either by using a hand rotatory duster or by dusting the fungicide onto the young leaves by tapping the sac made out of cloth, containing sulphur dust.
The young plants in the field should also be protected from the severity of sun. Plaited coconut leaves can be used for covering one-year-old plants in the field.
Two to four-year-old plants which are likely to be exposed to the sun, should be protected by applying a coat of lime from the bud union to the first branching region. Such protection should be given on the side, most affected by hot sunlight. Copper sulphate need not be added to the lime. White washing should be done only on the brown coloured bark of the plants.
Branches dried due to pink disease should be cut and the cut surface be applied with Bordeaux paste.
The base of young plants in the field should be mulched using dried leaves, grass or cover crop. Mulching should be done leaving 5 to 7.5 cm from the plant base. Mulching will help the plants to protect the plant base from scorching in the severe summer.
Precautions should be taken to prevent fire hazards in rubber plantations well in advance. This is best done by taking fire breaks (fire belts) around the plantations. A belt of 5-7m width should be maintained by clearing all dried leaves and shrubs and other plants. It is also better to insure the plantations against hazards like fire and storm.
In powdery mildew disease-prone areas, arrangements for procuring sulphur and servicing the dusters may be made in advance of the wintering.