Growth and competitiveness of common lambsquarters (Chenopodium album) after foliar application of Ascochyta caulina as a mycoherbicide
1996
Kempenaar, C. | Horsten, P.J.F.M. | Scheepens, P.C.
Control of common lambsquarters by the use of Ascochyta caulina as a postemergence mycoherbicide was studied in corn and sugar beet, in 1992 or 1993. The weed was planted at determined positions in the crops. Plots were treated with suspensions of A. caulina spores, and wetness duration's were varied to create different levels of disease development. Application of A. caulina resulted in necrosis development on, and mortality of common lambsquarters. Average severities of leaf necrosis 1 wk after treatment ranged from 0.01 to 0.75. Average proportions of dead plants 3 wk after treatment ranged from 0.00 to 0.65. Necrosis development and mortality were affected by wetness duration in two experiments. Sublethally diseased plants showed reduced growth. Maximum dry matter was affected by crop and by necrosis development. Numbers of fruits per plant showed a positive, almost linear relationship with plant dry matter weight. Seed weight was less affected by necrosis than number of fruits per plant. Competitiveness of common lambsquarters was reduced after infection by A. caulina. Crop dry matter weight showed a positive relationship with the level of common lambsquarters control. In corn, yield reduction by competition was prevented by application of A. caulina, but not in sugar beet.
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