UBC Theses and Dissertations
The effect of various chemicals as selective herbicides for British Sovereign strawberries (Fragaria chiloensis) Freeman, Jack Allen
Five experiments in all were carried out with the object of studying the use of selective herbicides on British Sovereign strawberries. Before laying out a large replicated experiment it was felt that (a) the general response of strawberry plants to various herbicides and (b) the effect of these herbicides on both broad-leaved weeds and grasses should be determined. Small plots were laid out on a three year old strawberry plantation and subjected to 34 different treatments (Experiment I). Similar treatments were applied in Experiments II and III to newly seeded and established grasses. These treatments consisted of different concentrations and mixtures of the following: 2,4-dichlorophenoxyaeetie acid (2,4-D) Sodium salt of trichloroacetic acid (TCA) Ammonium salt of isopropyl N-phenyl carbamate (IPC) 2 methyl-4-chlorophenoxyacetic acid (MCP) Sodium pentaehlorophenate (POP) Ammonium salt of dinitro-O-secondary butyl phenol (DNOSBP) Potassium cyanate Emulsifiable pentachlorophenol The effects of these treatments on the strawberry plants, grasses and broad-leaved weeds are reported and discussed. In the final experiment six treatments (2,4-D and 2,4-D plus IPC) were laid out in three replicates on a maiden British Sovereign strawberry plantation. Treatments of 1, 2, 3 and 4 pounds of 2,4-D per acre and 2 pounds of 2,4-D plus 40 pounds of IPC per acre were compared with a hand-weeded check. It was found from these experiments that (1) the sprays should be applied when the weeds are small and succulent, especially is this true for annuals; and (2) that under conditions of this experiment a mixture of 2 pounds of 2,4-D plus 40 pounds of IPC can be safely recommended for the deweeding of British Sovereign strawberry plantations provided it is not used when the plants are in blossom.