Green manures: Order seed now for planting at the end of this month.
The Caliente mustard range from Plant Solutions will increase soil organic matter levels and also provide additional biofumigation benefits. Green manures need to be managed like any other field crop.
Sclerotinia: Often attacking the plant crown first, this disease can leave roots intact but cause girdling and collapse of the tops. White fan-like mycelium forms over the plant and potting medium. Amistar (SOLA 2009-0443) or Rovral WG provides control along with Contans WG.
Downy mildew: Differences in day and night temperatures are producing lots of morning dew, encouraging this disease on plants including Impatiens, rose, Digitalis, Geum, Geranium and Osteospermum. Control with Aliette 80WG, Fubol Gold WG (SOLA 2010-0567), Filex/Proplant, Invader (SOLA 2011-0717), Signum (SOLA 2009-1842), Subdue or Triptam plus a wetting agent. Valbon (SOLAs required) has approval for outdoor ornamentals and amenity plantings.
Scab: Watch the weather to check for vulnerable times of scab infection on Malus, Pieris, Chaenomeles and Crataegus. Avoid routine fortnightly sprays and read the weather instead. Scab can also be created under overhead irrigation, particularly on protected crops. Amistar (SOLA 2009-0443), Bumper 250EC (SOLA 2009-0707) or Systhane 20EW can be effective on glasshouse and tunnel crops. Outdoors, eradicants include Radspor FL, Topas and Systhane 20EW. If scab is present, use an eradicant followed by a protectant.
Powdery mildew: Check Acer, Aster, Crataegus, Euonymus, Euphorbia, hops, Lonicera, oaks, miniature roses, Solidago and Verbena. Use Amistar (SOLA 2009-0443), Bumper 250EC (SOLA 2009-0707), food-grade potassium bicarbonate, Nimrod or Systhane 20 EW. Emulsifiable concentrates can cause scorch on sensitive young foliage. Outdoor crops have Cyflamid (SOLA 2007-0512), Stroby WG, Lyric and Folicur for longer-term control.
Leaf miner: Flies lay eggs inside leaf tissue that grow and feed, leaving distinctive meandering trails. Early introductions of Dacnusa and Diglyphus parasitic wasps can be used under protection or spray with Calypso (SOLA 2006-3728), Dynamec or Hallmark WZT (SOLA 2008-2944).
John Adlam, Managing director, Dove Associates