3 May - Bees and disease

BEES Review your chemical store list and check all product labels for any specific information on bees. Avoid spraying anyway when bees are foraging -- usually early morning or late evening, depending on the weather.

Notify local beekeepers if spraying flowering crops. Environmental Information Sheets for pesticides will help informed decisions on side-effects for bees and other vulnerable non-target organisms.

Pythium and Phytophthora Avoid overwatering vulnerable plants including Chamaecyparis, Cytisus and Taxus. Control active infections using Fenomenal (EAMU 2013-1990) or Subdue. Repopulate composts with micro-organisms using Prestop (EAMUs required), Serenade ASO (EAMUs required) or Trianum P.

Caterpillars Time to install pheromone lures inside Delta traps over vulnerable protected crops to identify damaging species this season for focused IPM-friendly spray applications. Outdoors, when appropriate, control on Betula, Cratageus and Carpinus using Decis, Dimilin Flo, Insegar WG, Runner (EAMUs required), Steward (EAMU 2008-2905), Toppel 100 or Tracer (EAMU 2008-2908).

Aphids A key month for sudden population increases. Check glasshouses and tunnels but also warm, sheltered areas on outdoor beds. Lacewings and ladybirds released into living windbreaks will assist with on-site controls alongside IPM-friendly pesticides. Use Chess WG (EAMUs required), Eradicoat, Majestik, Movento (EAMUs required), Naturalis-L, Pyrethrum 5EC, SB Plant Invigorator or Spruzit. Also check ornamental cherries and Viburnum carcephalum.

Feeding Change to high-nitrogen liquid feed products on nursery stock using a 2:1:1 on sprinkler systems and 2:0:1 on drip systems. Avoid applications on warm, sunny days to prevent scorch. Add the second top dressing of nitrogen to tree crops according to your fertiliser programme, but do not exceed 50kg/ha of N (150kg/ha ammonium nitrate).

Sawfly Aquilegia, robinia, older roses on site, Tilia and others are susceptible. Check for small, green caterpillars that will quickly defoliate plants. Spray outdoor crops with Decis, Dimilin Flo or Tracer (EAMU 2008-2908).

Fireblight Check Rosaceae subjects, especially ones that bore flowers last year. Prune and burn all suspect plant material. Note that cold damage and old scab infections have similar symptoms.

Willow anthracnose Apply Bravo 500 (EAMU 2011-1130), Amistar (EAMU 2017-0965), Folicur, Signum (EAMU 2012-2141) and Switch through the spring (and summer) to prevent stem dieback and unsightly large cankers.

John Adlam - managing director, Dove Associates

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