MATERIALS AND METHOD
The experiment was conducted at Henderson Research Institute during the 2018/19 cropping season. A Randomized Complete Block Design (RCBD) with 5 treatments replicated 4 times was used and the treatments were as follows:
- Control (no herbicide)
- Stellar Star 700ml/ha + Atrazine 3.6L/ha (Standard)
- Nicosulfuron 40g/ha
- Nicosulfuron 45g/ha
- Nicosulfuron 50g/ha
Maizefert (7:14:7) was applied as the basal fertiliser at planting at a rate of 400kg/ha. Ammonium Nitrate (34.5%) was applied as a top dressing at a rate of 400kg/ha split applied at 3 weeks and 6 weeks after emergence. The measurements taken were weed counts before spraying, 7 days after spraying (DAS), 14 DAS, 21 DAS and 28 DAS. Samples for weed counts were done by randomly throwing quadrates measuring 30cm x 30cm at three random positions of the plot. Weeds were sampled for dry matter determination at physiological maturity. Weed data was subjected to analysis of variance (ANOVA) using the Genstat package. Treatment means were separated using Fisher’s Protected Least Significant Differences (LSD; P<0.05). The European Weed Research Council Scoring s
System (EWRCS) were recorded at the same time when weeds were counted using a scale of 1-9.
The results showed that Nicosulfuron at 50g/ha is effective to most weeds including Rottboellia cochinchinensis (Shamva grass) andno phytotoxicity was observed to the maize crop.
Nicosulfuron is recommended as a post-emergent selective herbicide for controlling a wide range of both broadleaf and grass weeds in maize. However, the herbicide should be sprayed whilst the weeds are at the seedling stage (2-4 leaf stage) for more effective control.
Nyasha Rushwaya (Research)