27 April - Take a targeted approach to pests

Whitefly: Predators will struggle to control high numbers of whitefly adults.

Order combinations of Encarsia and Eretmocerus when the scale stage is found. Hang cards away from sun and direct irrigation. Rotate sprays on ornamentals crops using Chess WG (EoA 2008-2834), Intercept 70WG, Majestik, Mycotal, Naturalis-L, Oberon (EoA 2004-1718), Pyrethrum 5EC, Savona and SB Plant Invigorator. For non-IPM systems, include Decis, Gazelle SG, Spruzit or Toppel 100EC. Spray three times at five-day intervals.

Sciarid fly: Larvae are increasing in numbers now at propagation and liner stages. In small areas, install yellow sticky traps to attract adults away from compost surfaces. Change weekly if populations are high. Drench with nematodes (Steinernema feltiae) or introduce Hypoaspis or Macrocheles mites. Larger areas can be treated with the rove beetle Atheta coriaria. Products available for ornamentals include Decis (non-IPM), Dimilin Flo, Intercept 70WG or Met52.

Leaf-curling aphids: Control emerging pests on ornamental cherries and other plants such as Viburnum carlcephalum with Calypso (EoA 2008-2831), Chess WG or Gazelle SG, which will provide good control even if pests have distorted foliage.

Vine weevil: Larvae are active in untreated containers. Non-edible saleable crops can be drenched with Intercept 70WG if there is no other neonicotinoid product in the compost. Nematodes can be applied to saleable crops (>5 degsC) and come in various pack sizes. Met52 can be incorporated into new batches of growing media or applied around established ornamentals and amenity vegetation using EoA 2011-1997 or 2011-1568.

Slugs: Apply pellets such as Sluxx to anemone, ajuga, arbutus, campanula, choisya, clematis, Cordyline, euonymus, hemerocallis, hosta, Houttuynia, Iris, lavatera, yucca and herbs including basil, mint, thyme and sage. In damp conditions, consider also the nematode Phasmarhabditis megidis.

Western flower thrip: Control scratching or flecking on leaves and flowers with Conserve, Dynamec or Naturalis-L. Apply Amblyseius cucumeris to foliage for adult and nymph control and Atheta coriaria, Macrocheles robustulus and Met52 (EoAs required) to compost to control pupa. Use blue sticky traps to monitor populations.

John Adlam, Managing Director, Dove Associates

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