Cultural Operations : September
The land selected for raising the nursery may be dug to a depth of 75 cm. All the stumps, stones and brushwood may be removed and the soil is brought to a fine tilth. Beds may be prepared with 90 to 120 cm width and of convenient length. In slopes, beds should be made along the contours. Pathways may be laid in between the beds for facilitating manuring, watering, weeding, etc.
Seeds available now can be sown in the germination beds. The seeds sprouted each day should be picked and planted in the nursery beds.
Planting for raising bud wood nurseries can be done now with polybag plants or budded stumps. If different clones are used for planting, they may be planted in separate rows with sign boards for identification. The recommended planting distances for brown bud wood nursery is 90 x 60 cm and for green bud shoot nursery 1 x 1m or 90 x 90 cm.
In newly established bud wood nurseries fertilizer application can be done two or three months after planting the budded stumps. Application of 10-10-4-1.5 NPKMg mixture at the rate of 125 gm per plant is recommended two to three months after cutting back for the second and subsequent crops of bud wood from the nursery.
Immature plants, including those planted during current planting season can be manured now. The application of fertilizer should be undertaken after cessation of south-west monsoon but before the onset of the north-east monsoon. Sufficient moisture in the soil should be ensured at the time of application of fertilizer and the chances of loss through leaching should also be avoided.
Manuring of cover crops is also essential for proper growth and establishment in plantations. Application of 150 kg of powdered rock phosphate per ha in two equal instalments is recommended. The first application can be made two months after sowing. In areas which are deficient in available potassium, application of a mixture of 150 kg of rock phosphate and 50 kg of muriate of potash may be made. The fertilizer can be applied broadcast on the cover crop planted strips.
Pink disease usually occurs during south – west monsoon period, but severe incidence and drying up of the plant / branches are noticed from August to November. Inspection of each tree in young plantation at fortnightly interval is essential to detect the disease at early stage for effective control. As soon as the infection is noticed, Bordeaux paste may be applied on the infected parts. The dried branches should be pruned off and burnt. Thiride 10 g/kg in rubberkote or systemic fungicide like Tridemorph (Calixin) 1% or propiconazole (Tilt) 0.1% in pidivyl–china clay (1:2:4 by volume) is also effective.
Patch Canker is noticed in the wet monsoon months. The loci of infection could be anywhere on the stem. Copious exudation of latex is the main symptom. The exudates later dry up to form a black streak below the affected portion. Simultaneously latex coagulates under the bark at the site of infection forming a pad. The disease affected portion may be cleaned thoroughly by removing the rubber pad and damaged or rotten tissues and then fungicide solution may be applied at this region. Fungicides like Dithane (Indofil) M-45 (10 g/L of water) may be applied. When the fungicide is dried, application of a wound dressing compound like rubberkote may be made for protecting the tapping panel.
Wherever tapping is continued in rainy season, the tapping panel should be protected from bark rot disease. For this purpose fungicides like Dithane (Indofil) M-45 (5 g/L) or Akomin or Phosjet (2 ml/L of water) may be applied on tapping cut at weekly intervals.
Spraying with 1 % Bordeaux mixture at fortnightly intervals on the tender green shoots and on the tender leaves of young rubber protects from disease like shoot rot and other leaf diseases. Colletotrichum leaf disease is severe during July – October in young plantation. In such areas alternate fortnightly spraying with Dithane (Indofil) M-45 at the rate of 2.5 g/L of water is recommended.
False shoot, if any, sprouting from the stock of bud-grafted plants should be removed and only one vigorous bud shoot may be allowed to develop. Further pruning may be carried out appropriately in field-planted plants to remove any side shoots developing up to 2.5 m from the ground level.
The growth of weeds is fast during monsoon season and weeding should be carried out during every month. The weeds so removed may be kept in plant rows. These weeds when dried can be used for mulching the plant bases.
New planting / Replanting / Vacancy filling
Planting can be carried out using polybag plants, if there is sufficient moisture in the soil.
Yield stimulants like ethephon (Ethrel) may be applied during the month if there is no rain. Use of stimulants thrice a year is recommended for trees which are under tapping for more than 15 years and once in a year stimulation is recommended for trees which are tapped between 10 and 15 years. The ready to use formulation of ethephon available in the market usually contains 10% active ingredient. The 10% formulation can be diluted to 5% with palm oil, petroleum jelly, coconut oil or even with water. But water-mixed formulation should be used immediately. It should not be kept for more than two hours. However, if low frequency tapping (LFT) system is adopted, schedule of stimulant application as per the standard recommendation may be followed.