Vol. 8, Issue 8, Part L (2024)

Wheat (Triticum aestivum L.) is the second most important food crop of India next to rice but wheat fields are generally infested with a large number of weeds. Due to their highly competitive ability and allelopathic interference, weeds cause irreversible damage to the crop. Weeds survey and Phytosociological studies have been conducted in the wheat fields of major districts of south Bihar namely Buxar, Rohtash, Bhojpur, Aurangabad, Jahanabad, Nawada, Nalanda, Patna and Gaya, Bihar, India during the period 2014-15 and 2015-16.The survey has been carried out at 100 randomly selected wheat fields and well explored covering all the major wheat growing areas of south Bihar, to identify the weed flora, species composition, density, frequency and importance values index (IVI). Phalaris minor, Chenopodium album, Lathyrus aphaca, Vicia sativa, Cirsium arvense, Anagallis arvensis and Rumex species are dominant in wheat crops. Four major weeds were dominant in all districts of South Bihar viz. Phalaris minor, Chenopodium album, Lathyrus aphaca, Vicia sativa. In canal irrigated area crops are badly affected by Phalaris minor, Parthenium hysterophorous and Polypogon monspeliensis weeds. Canada thistle (Cirsium arvense) weed was found to be increasingly affecting wheat, lentil & chickpea in last five years.