Prevalence of weed flora of transplanted rice in different regions of Haryana

Floristic composition of weeds in transplanted rice was studied by surveys of 199 fields in eight rice growing districts of Haryana state during July-August, 2011 and importance value index (IVI) of individual weeds was calculated by pooling average values of observations of relative density and relative frequency. In all, 28 weed species (7 grassy, 7 sedges and 14 broadleaf) were found to infest rice fields in Haryana. Grassy weeds Echinochloa colona and Echinochloa glabrescence were major weeds found to infest rice fields in all the districts. Similarly, Ammania baccifera with IVI values of 1.6–36.8 among broadleaf weeds and Cyperus rotundus, Cyperus difformis among sedges were also present in all the districts. Broadleaf weed Caesulia axillaris, although with low density, was present in all the north-eastern districts except Karnal whereas presence of this weed was not noticed in any district of south-western Haryana. Sedge Scirpus supinus with IVI of 6.0–36.0 was present in all north-eastern districts except Panchkula and Jind, whereas in south-western districts, it was present only in Jakhal area of Fatehbad and Beri block of Jhajjar district in rice grown under semi-aquatic situations. Leptochloa chinensis, a new emerging grassy weed with IVI values of 11.7–22.6, was rated as one of the important grassy weeds that was found to cause yield losses in light textured soils in all parts of state except Ambala, Hisar, Jind, Rohtak and Jhajjar districts.