Naturally occurring phytotoxins in allelopathic plants help reduce herbicide dose in wheat

Abstract

Field studies were carried out to evaluate the influence of allelopathic plant water extracts applied alone or tank-mixed with a reduced herbicide dose on the weeds of wheat. Water extracts of sorghum (Sorghum bicolor (L.) Moench.) + sunflower (Helianthus annuus L.) + mulberry (Morus alba L.) were used alone (each at 20 L ha^–1) or combined with iodo + mesosulfuron (3.6 and 7.2 g active ingredient (a.i.) ha^–1; 25 and 50% of the recommended dose, respectively). The recommended dose of herbicide, a weedy check and a weed-free treatment were included for comparison. Allelopathic water extracts alone suppressed the density of canary grass (Phalaris minor Retz.) and wild oat (Avena fatua L.) by 34–42%, and dry weight by 59–67%. The mixture of allelopathic plant water extracts combined with reduced doses of iodo + mesosulfuron gave weed control equal to the recommended dose of the herbicide. Integration of plant water extracts with reduced herbicide rates provide effective weed control and a wheat yield comparable to using the recommended herbicide dose.

Keywords:

• phytotoxins
• allelopathy
• water extracts
• reduced herbicide dose
• iodo + mesosulfuron, isoproturon + carfentrazone
• weed suppression