1 September 2022

Pasture renewal required after grass grub/porina damage

Region: Hawke’s Bay, Manawatu-Wanganui, Marlborough, Nelson/Tasman, Otago, Southland, Taranaki, Wellington,West Coast, Canterbury, Gisborne

For pastures badly affected by either grass grub or porina over winter and needing renewal consider direct drilling. This will preserve naturally occurring diseases of these pests that are building up in the soil and which will provide long term population regulation. Leave sowing as late as possible as both pests, especially in the south, may still be feeding and could devastate establishing seedlings. Be aware that slugs and clover root weevil may also be present in damaging numbers.

Direct drilling new pasture?

Region: All of NZ

If pasture establishment by direct drilling is going to be used check those pastures for pests, especially slugs and feeding grass grub as even low numbers can devastate young seedlings of pasture or crop plants.

In yellow bristle grass infested pastures consider….

Region: Northland, Auckland, BOP, Waikato, Taranaki, Marlborough, Canterbury

If pasture is near the end of its life was infested with summer-active grass weeds (such as yellow bristle grass) last summer, consider growing a forage crop for one or two summers prior to sowing the perennial pasture. This provides the opportunity to selectively spray the summer-active grasses and prevent weed seeds from replenishing the seed bank and infesting newly sown pastures.
If your pasture is still strong but was infested with YBG consider locking it up for silage to reduce germination of YBG in the early summer. However, do not make it into hay as that will only spread the YBG.

Ordering grass seed?

Region: All of NZ

When ordering grass seed select suitable endophytes and check that the endophyte you select has been assessed in the grass variety you order. In ryegrass, AR1 and AR37, and diploids with NEA2 , will protect against Argentine stem weevil, AR37, Endo5 and NEA2 against black beetle and AR37 against porina. See DairyNZ Pasture Renewal Guide for a guide to endophyte selection or the cultivar selector at www.dairynzfvi.co.nz

Endophyte levels in the seed should be at least 70% and have been assessed in the last 3 months.

Clover root weevils in pasture may reduce amount of N fixed by clover.

Region: All of NZ

In established pastures with high levels of clover root weevil the clover may be adding little in the way of nitrogen to the pasture and compensatory nitrogen applications may be required.

Northern North Island watch for clover flea damage to clover

Region: Auckland, Waikato, Northland, BOP

In Northland, South Auckland, Waikato and the Bay of Plenty watch for clover flea damage to clover and treat early if required to maximise effectiveness.


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