Bed watering Automatic irrigation can have an uneven output so check crops along bed edges and pathways for drought. Keep different compost types and pot sizes separate as much as possible. Start an irrigation efficiency drive with water shortages looming.
Spider mites Ensure Apollo 50SC (EoA 2001-2271) is applied to outdoor acer, Malus, prunus and Pyrus and vulnerable protected crops to control emerging mites and overwintering eggs. Weekly applications of SB Plant Invigorator can give some knockdown effect before predators are used. Predatory mites need an artificial "bridge" such as fleece if foliage is not touching so they can move across plants. Apply predators at the higher rate of 20/mt2 if this is not possible. Insecticides with a relatively short persistence on foliage include Dynamec, Majestik, Masai and Naturalis-L. Other more persistent products include Envidor (EoA 20012-0254) or Oberon (EoA 2004-1718) but these should not be used on Cordyline.
Downy mildew On buddleia, digitalis and geum, infections produce angular patterns on leaves that can appear randomly. Do not confuse this with nematodes, which produce similar damage but usually feed from the base of the plant upwards. Infection on hebes can show as yellow growing tips. Control with Aliette 80WG, Amistar (EoA 2009-0443), Fubol Gold WG (EoA 2012-0217), Invader (EoA 2011-0717), Paraat (EoA 2011-2585), Signum (EoA 2009-1842), Subdue or Valbon (EoA 2011-1123).
Tarsonemid mites These tiny pests can cause stunting, distortion and galls on aster, azalea, cyclamen, Fatsia and other ornamental crops including trees. Useful insecticides include Apollo 50SC (EoA 2001-2271), Envidor (EoAs required), Sequel (EoA 2009-3061) and Hallmark WZT (non-IPM, EoA 2008-2944). Predators Amblyseius cucumeris, A. andersoni and A. californicus will feed on these mites.
Lupins The seed-borne disease Colletotrichum produces tell-tale spiralling of foliage with darkened and fallen stems. Gain some control with Octave or Switch.
Shot hole Overhead irrigation can produce an ideal environment for bacterial infections to spread on prunus spp. Irrigate plants and then apply Cuprokylt, Serenade ASO (EoA 2009-0246) plus a wetting agent. Leave foliage dry for at least 24 hours.
John Adlam, Managing Director, Dove Associates