Vine weevil: Larval activity will start as soon as growing-media temperatures in tunnels and cold glass get above 6 degsC. Check those ornamental subjects you know were not protected during the egg-laying time last autumn and take action by drenching with Intercept 70WG, avoiding frosty conditions. You can also apply nematodes if the growing-media temperature is consistently above 6 degsC.
Fuchsia cuttings: Check closely for the notifiable gall mite on new batches of cutting material and all bought-in material. Do not spray against the pest before rooting because some products have leaf cuticle softeners that can increase moisture loss during this critical period. Spraying once rooting has commenced allows young plants to replenish internal moisture levels. Applications of Talstar 80 Flo (non-IPM systems), Sequel (SOLA required) or Dynamec are effective when applied three times in rotation at four-day intervals.
Oaks: Oak midge can damage the growing tip on young field-grown trees, spoiling straight growth. Apply Gazelle, Actara (SOLA 2008-2801) or Vydate 10G (SOLA 1993-0020). One of these products, applied in the next two weeks, will ensure that the active ingredient is taken up when the sap rises. This should control the midge inside the terminal bud.
Glasshouse computers: Routinely check temperature, humidity, vent and screen settings and re-adjust where necessary. If you have a variety of crops throughout the year in a house, do not just leave the settings the same but change them to get the optimum growth from the crop.
Moles: There has been a surge in mole activity over the past few weeks after the cold and wet weather. Control them before they breed and have young. Trapping is the common way of control but does need skill and care to be effective. Gas tablets can be very effective but make sure that your staff are trained and qualified to administer them.
Foliage yellowing: Newly-emerged leaves that are yellow on Cytisus, Potentilla and Ceanothus are due to an iron deficiency but also because root development is not keeping pace with foliage development. Cold spells mean low growing-media temperatures, slow root development and slow controlled-release fertiliser, but daytime temperatures can allow some foliage growth. Water the compost with an iron chelate EDDHA at the rate of 100g/10 litres diluted at 1:200.