IPM: Start to plan your biological control programme to be ready to order on time.
The hard winter will have knocked pest populations down, but keep monitoring vulnerable plant species. Remember to order a mix of Encarsia plus Eretmocerus as soon as you see any stage of whitefly. Using a combination of both predators should increase the numbers of infected scale and provide better control.
Met52: A new product that controls vine weevil larvae is being launched by Fargro. It works well in a range of growing media, is compost-incorporated and based on a naturally-occurring soil fungus, Metarhizium anisopliae. The HDC has carried out extensive work on this fungus and members can find details on project HNS 133 on its website.
Helleborus: With these plants being despatched early it is important to keep them clean. Check leaves and stems for the black patches and concentric rings that occur from Coniothyrium hellebori. Control with sprays of Switch, Scotts Octave or Cercobin WG (SOLA 2008-1384).
Frosts: We may not have seen the last of the snow yet and this is often a month of mixed weather. Clear days are often paid for by frosty nights. Make sure you still have fleece ready to cover crops if a really cold spell develops and keep an eye on exposed irrigation pipe work and valves.
Phytophthora: Consider drenching Aliette 80WG, Previcur Energy (SOLA 2008-2667), Filex/Proplant, Subdue or Serenade ASO (2009-0246) to Chamaecyparis species to suppress Phytophthora in the growing media or in field production. Cytisus also benefits from an Aliette 80WG drench to control Pythium root damage, which can also be the cause of yellow emerging foliage. Subdue or Previcur Energy added to the growing media at mixing time also provides some protection to this group of plants through the first potting season. A new product called Prestop is released this month which is a biological control of Phytophthora sp. and can be compost-incorporated or applied after potting.
Peaches: Time to spray against Peach Leaf Curl and Pocket Plums. These two related diseases, caused by Taphrina spp., are best controlled before flower and leaf emergence. Once they are seen it is too late. Spray Croptex Fungex or Cuprokylt FL tank mixed with Serenade ASO (SOLA 2009-0246) on all appropriate crops.
- John Adlam is managing director at Dove Associates