With very few post-emergence options available together with the need to remove weed competition early, bean and pea growers are being advised to find ways of getting the most from the pre-emergence herbicides that they intend to use. Agrovista has been looking at optimising herbicide programmes to suit most situations and to control the widest range of weeds possible, according to Dr. Mark Palmer, Technical Manager of Agrovista.
Mark points out that growers have lost a whole range of pulse herbicides. "Familiar active ingredients such as cyanazine, fomesafen, simazine, terbutryn and now trifluralin are no longer available and so we need to look for effective alternatives. Most of these alternatives are pre-emergence as post-em options are restricted. We only have Basagran SG to rely on for post-emergence broad leaved weed control in beans."
According to Dr. Palmer, one particularly useful alternative is the residual herbicide, Nirvana. Containing imazamox and pendimethalin, Nirvana is recommended pre-emergence in all varieties of vining peas, combining peas, winter and spring beans. "Nirvana provides a very comprehensive weed spectrum and we have been experimenting with it in order to achieve even better results and an even wider weed spectrum. Independent research and development work indicates that the specialist pre-emergence adjuvant, Grounded, helps the performance of Nirvana as well as other pre-em herbicides. Grounded improves the spray deposition pattern and increases adsorption onto soil particles, keeping the herbicide where it needs to be. This results in better overall performance and improved reliability of residual herbicides. It also reduces the risk of drift."
Mark reports that in BASF trials in spring beans the addition of 0.2 l/ha of Grounded to 4.5 l/ha of Nirvana applied pre-emergence improved the control of Black-bindweed, Redshank and Orache with the combination giving 100% control.
Mark has also investigated mixing Nirvana with other herbicides to make sure that the remaining weed species are adequately covered. "In spring field beans and combining peas Nirvana at 2.5 l/ha mixed with clomazone and Grounded gave improved control of Cleavers, Fool’s Parsley, Shepherd’s Purse, Groundsel and polygonums. We have also looked at Nirvana and Grounded with linuron. Previous dose response trials with linuron at 500 gms a.i/ha dose have demonstrated the additional control of weeds such as Chickweed, Hempnettle, Mayweeds and Small Nettle to the already comprehensive weed spectrum controlled by Nirvana."
The benefits of Nirvana are summarised by Jonathan Ball, BASF Legume Product Manager. "Nirvana controls the most important weeds in peas and beans, including Black-bindweed, Charlock, Common Chickweed, Common Poppy, Fat-hen, Fumitory, Henbit Dead-nettle, Knotgrass, Orache, Red Dead-nettle, Redshank, Speedwells and Scarlet Pimpernel. Imazamox enhances the control of several key weeds, such as Charlock, Black-bindweed, Cleavers and Volunteer Oilseed rape, compared with equivalent rates of straight pendimethalin."
He also reminds growers that if the pre-emergence window is missed, the only true post-emergence option in vining and combining peas and spring beans is now Basagran SG (bentazone). "Applied from the third node onwards, Basagran SG offers good control of Volunteer rape, Charlock and Chickweed."
Dr. Mark Palmer concludes "With the high demand for protein and a lot more land available for spring cropping this year, we are anticipating a significant increase in the area of pulses being drilled, particularly spring beans. Day lengths are getting longer and hopefully we are due some dry weather which will allow growers to get going with planting. One of their early priorities must be weed control. A well chosen pre-emergence spray applied under optimum conditions with an appropriate soil adjuvant will be the most cost-effective solution. One positive aspect of this year is that the soil will be sufficiently moist for residuals to work well," says Dr. Palmer.
Background Notes - Nirvana contains 16.7 g/l of imazamox and 250 g/l of pendimethalin, formulated as an emulsifiable concentrate, packed in 10 litre containers. It is recommended in combining peas, vining peas, spring field beans and winter field beans for the control of broad-leaved weeds including Black-bindweed, Charlock, Common chickweed, Common Field Speedwell, Common Fumitory, Common Poppy, Fat-hen, Henbit Dead-nettle, Ivy-leaved Speedwell, Knotgrass, Orache, Red Dead-nettle, Redshank and Scarlet Pimpernel. Nirvana is applied pre-emergence of the crop at a dose rate between 2.5 – 4.5 l/ha in 200 – 300 litres of water per hectare, with the dose rate depending on the crop, weed pressure, weed spectrum and length of persistence required.
For further comment and information please contact:Jonathan Ball, BASF on 0161 488 5785 or mobile 0771 7782768
