Box blight - This disease is still active so spray Buxus subjects with Scotts Octave, Cercobin WG (SOLA 1384-2008 for ornamentals) or Signum.
Aphids - Aphids are present on roses, honeysuckle, hebes, cherries and a range of herbaceous. There are still plenty of parasitised aphids so continue using products such as Chess WG, Plenum WG, Stalwart, Majestik, SB Plant Invigorator or Aphox to encourage natural predators. Black cherry aphids are present on cherries. This pest distorts the growing tips and is harder to control than some species of aphid; use Gazelle or Plenum WG.
Spider mites - Two-spotted spider mites are active. Give Ceanothus, Choisya, Malus, Picea abies, Fraxinus and cherries a close inspection. Hallmark with Zeon Technology or Gyro are effective products to use on outdoor crops as part of your resistance programme. For protected crops rotate Dynamec, Floramite 240 SC and Oberon.
Powdery mildew - This fungus is still persistent on roses, asters, Solidago, hops, hawthorn and oak seedlings. Clean up the white growth with an eradicant product such as Nimrod or potassium bicarbonate. Gain experience with Cyflamid and Switch, which can be put into the programme along with your older favourites.
Whitefly - Whitefly control is still necessary so at the first signs of larvae and adults introduce Encarsia formosa. Calypso (SOLA 3728-2006), Chess WG and Oberon are all fairly safe with IPM products. With whitefly you need to apply control products three times, five days apart, to ensure you reach all the hatching eggs and so break the lifecycle.
Tortrix moths - Tortrix moths are still egg laying at the moment so be alert. Spray with Chess WG, Conserve, Nemolt or Dimilin Flo to avoid spoiling your biological control programmes of other pests.
Western flower thrip - This pest continues to flourish on ornamentals under protection. Tap flower heads over a plain sheet of white paper and you often find that adults fall out of the flower where they are feeding on nectar. Repeated introduction of Amblyseius cucumeris gives good control and the spraying of Conserve will control most stages of the insect without harming the predators.
Carbendazim - A number of products containing carbendazim had a use-up date of 30 June 2008. Check through your products and MAPP numbers with the on-line PSD databases. An alternative product is Cercobin WG using the new SOLA1384-2008.
- John Adlam is managing director of Dove Associates.