Spraying: Avoid spraying emulsifiable concentrates onto soft foliage before, during and after warm, sunny conditions to reduce the risk of scorch damage, which can delay plant sales.
Products include: Corbel, Decis, Dynamec, Nimrod and Sumi-Alpha.
Adding in an adjuvant to your spray tank (check pesticide labels first) will help to control stubborn powdery mildew infections on roses and trees. With unsettled weather, adjuvants will also help to increase the time products stay on crops.
Scab: Check pyrus, sorbus, Crataegus, Malus, pyracantha and Chaenomeles. Monitor scab risk by using either the Mills or Smith tables, which use the weather conditions to calculate optimum spraying times.
Moths: Check vulnerable crops including acer, ash, birch, choisya, Crataegus, euonymus, Malus, oak, prunus and others. Install a range of pheromone lures attached to Delta traps to identify damaging species for timely spray applications of DiPel DF.
Prochloraz: For ornamentals, Octave (MAPP 11741) and Scotts Octave (MAPP 15756) have an end use and storage date of 30 June 2017. Scotts Octave (MAPP 09275) had an end use date of 30 June 2016.
Fremontedendron: Apply Fenomenal (EAMU 2013-1990) or Subdue to plants to control aerial dieback on stems.
Pinus: Check for weeping around buds, drooping stem leaders and stunted growth - a sign of pine shoot moth grub activity. Control larvae using Decis or Toppel 100 (EAMU 2015-1454).
Feeding: Change to high-potash (K) products to harden up soft foliage and green-up any pale older leaves. Use products including Hortifeeds 2:1:6, Peters Plant Finisher, Sangral 1:1:3, Solufeed 1:0:3, Universol Violet or Vitax 2:1:4.
Spider mites: Masai, Dynamec and SB Plant Invigorator are useful products at this time of year. Use predators on vulnerable crops too, checking pesticide compatibility first. Naturalis-L will provide good knock-down control in tunnels and glasshouses with less than 60 per cent humidity.
John Adlam, Managing director, Dove Associates, HorticultureWeek.co.uk/nursery