15 April - Beetles and mildew

Bark beetles: Apply Decis, Hallmark WZT (EAMU 2008-2944) or Toppel 100 (EAMU 2015-1454) directly onto stems of pines, cherries and other vulnerable crops to control emerging bark beetles.

Powdery mildew: Check emerging deciduous azalea foliage for early powdery mildew infections. Apply food-grade potassium bicarbonate, Nimrod or Signum (EAMU 2012-2141) followed by Systhane 20EW.

Capsids, midges & leafhoppers: Spray Calypso (EAMUs required) Decis, Envidor (EAMU 2012-0254), Hallmark WZT (EAMU 2008-2944) or Toppel 100 (EAMU 2015-1454) if holes or flecking (depending on the pest) are found on new growth. Chess WG (EAMU 2013-2016) will also prevent damage to buds and young leaves of Buxus, Caryopteris, choisya, dahlia, forsythia, hydrangea, Pyrus, Quercus and roses.

Bacteria: Avoid overhead irrigation in late afternoon on vulnerable Prunus spp. Apply Cuprokylt (EAMU 2015-1176), Serenade ASO (EAMUs required) plus a wetting agent and try to leave foliage dry for at least 24 hours after spraying.

Blossom wilt: Check cherries, plums, damsons and apricots. Apply Systhane 20EW (EAMUs required) to prevent infections and, should the disease be present, control with Indar 5EW (EAMU 2003-1372), Signum (EAMU 2010-2109) or Switch (EAMU 2010-3092).

Whitefly: Introduce Encarsia and Eretmocerus when the "scale" stage is present. Hang cards away from sun and direct irrigation. Alternatively, apply Chess WG (EAMU 2013-2016), Majestik, Mainman (EAMU 2013-0045) Naturalis-L, Pyrethrum 5EC, Savona and SB Plant Invigorator. For non-IPM systems include Decis, Gazelle SG, Spruzit or Toppel 100 (EAMU 2015-1454).

Box blight: Apply Octave, Signum (EAMU 2012-2141) or Switch to Buxus. Only prune plants in mild, dry conditions. Use sharp tools and disinfect blades in between batches of plants.

Leaf miners: Introduce Dacnusa and Diglyphus wasps or apply Calypso (non-IPM, EAMUs required), Conserve, Dynamec or Hallmark WZT (non-IPM, EAMU 2008-2944). Selected pheromone traps are also available.

Weeds: Spot treat outdoor perennial weeds using Depitox (EAMU 2008-2843), Dow Shield 400 (EAMUs required) or glyphosate products. Control grasses using Aramo (EAMU 2015-0454), Falcon or Laser.

EAMUs: Go to the Chemicals Regulation Directorate website (https://secure.pesticides.gov.uk/offlabels) to check on newly issued EAMUs since the beginning of this year. Some have been updated to reflect new end-use dates.

John Adlam, Managing director, Dove Associates

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