13 January - Larvae and spraying

Sciarid control: Control sciarid and shore fly larvae with nematodes (Steinernema feltiae) or introduce Hypoaspis sp. or Macrocheles mites.

Atheta coriaria can be used if compost temperatures stay above 15 degsC in winter. Root rotting from feeding damage can be prevented using Trianum P, Revive P or Serenade ASO (EAMUs required), or Prestop if cuttings have rooted. Install yellow sticky traps at regular intervals to attract adults away from compost surfaces and foliage. Change regularly for effective trapping and monitoring.

Spray records: Check spray records and make sure applications were carried out in line with your annual spray programme. Check that you are up to date with product labels, safety data sheets, EAMUs and product revocations.

Cold stores: Temperature and humidity levels can fluctuate on changeable days. Spray stored material with Rovral WG (EAMUs required) or Serenade ASO (EAMUs required) to protect against fungal growth.

Feeds: On older crops, check compost and water conductivity now, and then again in March, to check nutrient availability. Plants may need a top dressing or liquid feed boost going into the spring months depending on the type of slow-release fertiliser used in composts. Slow-release products such as Osmocote Top-Dress and Floranid Permanent will avoid leaf scorch issues. Include supplementary feeding of plants that show deficiencies of iron, magnesium, nitrogen or calcium during the growing season.

Vine weevil: Check regularly for larvae in pots of susceptible crops. Nematodes will only work in compost and soil temperatures that are consistently above 5 degsC.

Winter weeds: Products including Flexidor 125 and Butisan S can be applied in the dormant season. For bittercress, willowherb, pearlwort and mouse-ear chickweed, use Chikara, Devrinol (EAMUs required), selected products with pendimethalin, Shark (EAMU 2016-0099), Sumimax (EAMU 2008-2881) or Venzar Flowable. Bullet XL and Roundup control pearlwort. Chikara and Sumimax work on groundsel. Check crop tolerance by looking at AHDB projects HNS 111, 132, 139a, 155, 166 and 175. Check for product restrictions on what can be safely planted as a following crop. Once field-grown Abies and Picea crops are fully dormant, consider applying Roundup over them to control perennial weeds. Avoid applying herbicides to frozen land.

Azalea gall: Can be expected in January when damp. It can affect young leaves in tight foliage so get air moving around and in between crops. A preventive fungicide may be worthwhile, such as Bravo 500 (EAMU 2011-1130), Cuprokylt (EAMU 2015-1176) or Signum (EAMU 2012-2141) depending on the crop location.

John Adlam, Managing director, Dove Associates

HorticultureWeek.co.uk/nursery


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