Weedy Rice

  • Weedy rices show a wide variability of anatomical, biological and physiological features and are closely related taxa of O. perennis, O. nivara, O. rufipogon and O. longistaminata, O. glumaepatula, O. latifolia, O. punctata, O.Glaberrima and O. officinalis. These are vigorous growing and strongly competitive plants; and infestation of these wild rices in paddy fields, lower the quality as well as grain yields of cultivated rice.
  • A number of weedy and red-grained varieties were reported from the plains of Haryana, Punjab, Rajasthan, Western Uttar Pradesh, Gujarat, Tamil Nadu, Karnataka, Bihar, Orissa, West Bengal, Madhya Pradesh and the northeastern states.
  • Recently, the weedy rice has become a problem in direct seeded rice (and very rarely observed in irrigated transplanted rice) ,because of its ratooning ability, pre -harvest shattering of weedy- rice seeds as well as seed dormancy.

Preventive

  • Keeping a weed from becoming a problem. Includes the use of agricultural practices such as sanitation, quarantine and cultural methods. This is one of the most important control method of weedy rice. Destroying or removing a weed completely from a crop, an area, or a geographic region.
  • Pre planting control of weedy rice: Land preparation in dry soil followed by irrigation , application of Glyphosate to control emerging weed flushes including wild rice .

Cultural and mechanical

  • Land preparation provides favorable conditions for the growth and development of rice, as well as a weed-free condition at planting. Proper field preparation discourages the subsequent growth of weedy plants by allowing rice to establish itself and use the available resources before weeds germinate and emerge.
  • Pre-monsoon dry tillage may aid in killing vegetative organs of perennial weeds, provided that the storage organs can be exposed to the sun and dried.
  • Deep ploughing where the soil is completely inverted, will bury weed seeds lying on the surface deep enough, to inhibit germination and/or emergence. Adaptation of suitable crop rotations will aid in control of weedy rice.