United Kingdom

Vegetables

Protect your vegetable crop against pests, weeds and disease

Carrot pests and diseases

New viruses threaten carrot crops

Well established viruses affecting carrot crops are: Carrot Motley Dwarf (CMD) complex and Parsnip Yellow Fleck Virus (PYFV). Recent discoveries include: Carrot Yellow Leaf Virus (CYLV) and Carrot Torrado Virus (CaTV). Foliar symptoms are similar for many of the carrot viruses and can cause seedling death and severe plant stunting when crops are at an early stage. Typically leaves become yellow and reddish in colour. The main vector responsible for the transmission of these viruses is the Willow-Carrot aphid. Other possible vectors may include Peach Potato aphid and Parsnip aphid.

Monitoring crops for pests

Monitor crops closely when Rothamsted suction trap data indicates emergence of target aphids, using yellow water traps. Use in-field sticky traps to help monitor carrot fly activity and pest pressure.

Sclerotinia sclerotiorum

Increased cropping frequency and disease incidence threaten the majority of UK carrot crops. Encouraged by wet, humid conditions and a large canopy. Senescing foliage also makes a crop more vulnerable. Current fungicides are preventative and have no curative activity. Start fungicide programmes against Sclerotinia early, 60% ground cover, before canopy closure.

Alternaria Leaf Blight (Alternaria dauci)

Favours wet, humid weather. Early attack restricts canopy growth which reduces yield and quality. Infected dead tissue will also increase the risk of Sclerotinia and increase harvest losses when top lifting. Infections usually start in well developed crops on the older leaves.

Syngenta Solutions

Onion diseases

Stay alert for downy mildew

Downy mildew can be a devastating disease in the absence of a robust fungicide programme. Early, forward crops and warm weather conditions are conducive for downy mildew development. Start fungicides early – when crops reach 4 to 5 leaves. Use crop growth stage rather than date for starting applications. Keep intervals tight, 7 days is ideal for protecting new growth. Including a range of active ingredients with different modes of action ensures cleaner crops.