Leaf hopper These are a particular problem on sage and French lavenders. For lavender, options include Chess WG (SOLA 2007-0502) or Calypso (SOLA 2006-0453), which both have a 14-day harvest interval, deltamethrin (SOLAs required with most products having harvest intervals), Majestik or SB Plant Invigorator.
Aphids Are you keeping your aphid populations under control with predators? Make sure that you are using the right predator and check which aphid you are targeting. If you find that you are still not getting good control, consider adding Adalia bipunctata to the crop. This is an ideal product to support an Aphidius programme.
Grass weed control Aramo (SOLA 2008-2813) can be used over a wide range of outdoor shrub, heather and herbaceous subjects to control annual meadow grass. It can be applied onto mature grass even while it is flowering and is just as effective on perennial grass weeds.
Scale insects These are still mobile. Spray with Decis (non-IPM), Chess WG (SOLA 2008-2834), Majestik, Savona, SB Plant Invigorator or Spraying Oil. Short-term pyrethrin-based products such as Pyrethrum 5EC and Spruzit are also available. Sooty mould can be cleaned up with chlorothalonil. Check labels for edible crop approvals.
Fremontodendron Apply another spray of Aliette 80WG this month to control the aerial Phytophthora that can attack the stems. Include Euphorbia in this spray programme, but apply the products as a drench. Disease incidence can be linked to damp, humid weather.
Feeding Some of the sales this season have not cleared out because many crops as we would like, and I have seen a lot more plants being kept on nurseries for longer than expected. The result of this is that the nutrient supplies in the compost may not carry the plants through to the autumn or even next year - especially if a short-term product was used. Check the nutrient status of vulnerable crops and top dress with Floranid Permanent, Sincron or Osmocote Top Dress as required, maintaining plant freshness through the autumn. For sales next spring, make sure that this season's plants have CRF plugs added and an appropriate liquid feeding programme in place.
Scab Check Chaenomeles, Crataegus, Malus, Pyracantha and Pyrus for scab symptoms and maintain a spray programme - particularly during wet, humid conditions - with overhead irrigation.
John Adlam is managing director at Dove Associates www.HorticultureWeek.co.uk/nursery for recent articles