The new pre-emergence herbicide Nirvana offers pea and bean growers considerable flexibility in terms of weed spectrum, dose rates and programmes and should be a key product for growers to try out and gain experience of this spring, especially when many herbicides in these crops are to be revoked, says BASF.
Nirvana is recommended pre-emergence in all varieties of combining peas, vining peas, winter and spring beans. It has been tested successfully by PGRO over a number of years and has been found to be completely safe on all 23 varieties of combining peas on the NIAB/PGRO list, on 53 varieties of vining peas and on 10 varieties of field beans including all listed spring beans. No taints have been detected on combining or vining peas. Its excellent crop safety and lack of varietal restrictions makes Nirvana a flexible and easy product to integrate into a weed control programme, says John Young, BASF Pulse Crops Product Manager.
John explains that Nirvana shows excellent control of all the important weeds in pulses including Black-bindweed, Charlock, Common Poppy, Fat-hen, Knotgrass, Orache and Redshank as well as Common Chickweed, Fumitory, Henbit Dead-nettle, Speedwells, Red Dead-nettle and Scarlet Pimpernel. Nirvana combines imazamox, a new active to the UK, with the well known pendimethalin. These ingredients fit together well because imazamox offers enhanced control of several key weeds, including Charlock, Black-bindweed, Cleavers and Volunteer Oilseed rape, compared with equivalent rates of straight pendimethalin. This makes Nirvana a versatile and robust choice. It also gives useful bonus activity on certain grass weeds including Annual Meadow-grass.
"Growers have a choice of flexible dose rates according to crop, weed pressure, weed spectrum and length of persistence required. In combining peas and field beans, the maximum 4.5 l/ha dose rate offers long term persistence and excellent activity when under high pressure from difficult weeds such as the polygonums, whilst the 3.0 l/ha rate is targeted for more general use against moderate or average weed populations. In vining peas, dose rates are matched to soil type. For light soils, between 2.5 to 3.0 l/ha is recommended whilst on medium to heavy soils 3.0 to 3.5 l/ha should be used. Where Black-nightshade is a severe threat in vining peas, a programme of 3.0 l/ha of Nirvana pre-emergence followed by Basagran SG post-emergence is recommended," says John.
Jim Scrimshaw, Senior Technical Officer at the PGRO, comments that Nirvana shows excellent activity against the polygonums, Black-Bindweed, Redshank and Knotgrass. "Charlock is also effectively controlled, as is Chickweed. It also gives improved control of early emerging Volunteer Oilseed Rape when compared to pendimethalin alone."
"Maximum persistence of Nirvana is seen with the full rate of 4.5 l/ha and this may allow a 'one-hit' programme which could prove useful for the bean crop. In practice the 3.0 l/ha application appears to be a good compromise with the option of a further drop to 2.5 l/ha when considering mixing with clomazone to maximise Cleaver and increase Fool's parsley control. Growers should be aware that reducing the rate to 2.5 l/ha may compromise Nirvana's strengths in other areas of the weed spectrum, for example against the polygonums such as Black-bindweed, and reduced persistence. At PGRO, the full 4.5 l/ha of Nirvana reduced Cleaver numbers effectively and maybe a means of retaining the full weed spectrum whilst still achieving adequate Cleaver control," says Jim.
Use of Nirvana is permitted on any mineral soil including light soils as long as organic matter content does not exceed 10%. Seed should be drilled to a depth of 25mm of settled soil and fields prone to waterlogging avoided. As with the majority of pre-emergence herbicides, activity is enhanced by moist conditions after application.
Jim points out that this is the last year that UK growers have the use of several popular and effective herbicides in peas and beans. "Simazine, Reflex T (terbutryn + fomesafen), Opogard/Battalion (terbutryn + terbuthylazine), Fortrol (cyanazine) and Bullet (cyanazine + pendimethalin) will no longer be available. The loss of Fortrol has a knock-on effect on the popular post-emergence pea herbicides of Pulsar (bentazone + MCPB) and Trifolex-Tra (MCPB + MCPA), as their use is dependent on the addition of Fortrol. For this reason Nirvana is a useful replacement product that has the potential to fill some of the gaps arising from revocation and loss of active ingredients in this sector."
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 maximum dose rate of 4.5 l/ha in 200 – 300 litres of water per hectare.
