Critical period of competition and economic threshold level of infestation of sicklepod (Cassia tora L.) in cotton.
1992
Colita E.T. Jr. | Baltazar R.B.
The experiment was conducted in a field heavily infested with sicklepod (C. tora) at Matalam, Cotabato [Philippines], from September 1990 to February 1991 to determine the critical period of competition of sicklepod in cotton and its threshold level of infestation. Cotton plants need weed-free condition from emergence to maturity to obtain maximum yield. In the case of weeding that commenced at 20 days after emergence (DAE), seedcotton yield was optimum with 1,332 kg/ha. Weeding operation beyond this period resulted in yield reduction by as much as 30%. The stage of cotton growth critical to sicklepod competition was within 20 DAE. Density of sicklepod at 20/m could exert an overall reduction in boll number, boll weight, and seedcotton yield. Sicklepod must be controlled, therefore, as early as 21 DAE or when it reaches a density of 9 plants/sq.m..
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