Pea wilt (Fusarium oxysporum f. sp. pisi)
- Plants appear stunted and may become discoloured before shrivelling and dying.
- Wilt is a soil-borne disease which can occur in any pea growing area.
- It is generally confined to fields with a very long history of peas and may occur in patches or individual plants.
- It can cause substantial reductions in yield, but is effectively controlled by genetic resistance.
- See PGRO Pulse Agronomy Guide.
Downy mildew (Peronospora viciae)
- Individual or small groups of plants appear stunted or pale.
- Gray velvety fungal growth develops on the underside of leaves.
- This disease produces resting spores, which persist in the soil and initiate primary infections in young pea plants.
- Secondary infections develop in cool, damp conditions.
- Pods develop yellow patches on the surface and a cottony growth on the inner pod wall.
- See Technical Update TU33 and the PGRO Pulse Agronomy Guide and Vining Pea Growers Guide for varietal resistance.
Leaf and pod spots (Ascochyta pisi, Mycosphaerella pinodes and Phoma medicaginis)
- A. pisi produces brown to grey rounded lesions with pin-prick sized fruiting bodies (pycnidia).
- M. pinodes produces numerous purple-black small lesions on stems and foliage. Lower stem may become black.
- P. medicaginis produces smaller dark lesions and black stem girdling.
- Leaf and pod spots are spread by seed infection, soil or plant debris.
- The most frequent is M. pinodes, which can cause losses in both yield and quality in wet conditions.
- The use of disease-free seed will help to reduce the incidence of disease.
- See Technical Updates TU33 and TU12.
Botrytis, or grey mould (Botrytis cinerea)
- Botrytis produces brown, watery rot with a grey furry mould.
- This can affect stems and pods during wet weather.
- It is initiated when petals stick to plant parts after pod set.
- See Technical Update TU12.
Powdery mildew (Erysiphe pisi)
- Powdery mildew is characterised by irregular areas of powdery white fungal growth on the upper leaf surface and pods.
- The disease can delay maturity.
- The disease can adversely affect the flavour of processed peas.
- See Technical Update TU12 and the PGRO Vining Pea Growers Guide.
Foot and root rots (Fusarium solani f. sp. pisi, Phoma medicaginis var. pinodella)
- The diseases produce areas of pale discolouration, stunted plants and yield reduction.
- Plants can be brown or black at soil level.
- Roots are often brown.
- The effects of these diseases are particularly common on heavy land with a history of frequent pea cropping.
- A predictive soil test is available from PGRO.
Sclerotinia, or white mould (Sclerotinia sclerotiorum)
- S. sclerotiorum causes a stem rot rather than a foot rot.
- Dense, white mycelium cover stems and pods.
- Stems collapse in a watery soft rot.
- Infected stems and pods may contain black, elongated resting bodies.
- The disease affects peas, spring beans, oilseed rape, linseed, and sometimes potatoes and certain field vegetables.
- See Technical Update TU12.
Bacterial blight (Pseudomonas syringae pv. pisi)
- This is a potentially serious seed-borne disease, which can occur on all types of peas.
- Symptoms consist of water-soaked brown lesions on the lower leaves, stems and stipules.
- The lesions may coalesce and show a fan shape on the leaf, between the lines of the veins.
- Some pod spotting may occur.
- Severe infections have not occurred in spring-sown peas and effect on yield has been negligible.
- See Technical Update TU32.
Pea and bean weevil (Sitona lineatus)
- The adult is 4-5 mm long with a narrow body, short snout and angled antennae.
- The larva is white and legless with a brown head.
- The pest causes damage to spring sown crops if large numbers appear when plants are small.
- Leaves of attacked plants show characteristic ‘U’ shaped notches around the edges.
- The main damage occurs as a result of the larvae feeding on the root nodules.
- See Technical Update TU08.
Field thrips (Thrips angusticeps)
- Field thrips are black, 1-1.5mm in length and are found in enfolded leaflets.
- They feed on the leaf surface of emerging seedlings.
- Foliage becomes thickened and puckered.
- Seedlings may appear pale in colour.
- In the majority of cases the peas will outgrow the effects of thrips.
- See Technical Update TU07.
Pea aphid (Acyrthosiphon pisum)
- Pea aphid adults are 1-2 mm long, bright green, pear shaped with slightly dark legs and have distinctive red eyes.
- Aphids can cause severe yield loss when feeding in large colonies.
- Aphid feeding causes growth distortion of foliage and pods, and abortion of flowers.
- Early infestations can result in crops becoming infected with pea enation mosaic virus.
- See Technical Update TU05.
Pea moth (Cydia nigricana)
- The pea moth has a wing span of 12-15mm, is silvery-brown in colour with indistinct black and white markings on the wing tips.
- The larva is creamy white, with a brown to black head and is up to 6mm in length.
- The larvae feed upon the developing seeds within the pod.
- Yield loss is minimal, but the effect on quality can be dramatic.
- Damage to the seed reduces the value of the produce.
- An automatic telephone forecasting service is provided by PGRO on 01780 783099.
- See Technical Update TU03.
Pea cyst nematode (Heterodera gottingiana)
- Affected plants are stunted and pale, and the root systems do not develop nitrogen-fixing nodules, but become studded with white, lemon-shaped cysts.
- Infestations occur in distinct patches that vary in size.
- Pea cyst nematode is a very persistent soil-borne pest, often causing severe yield loss.
- Frequent cropping of peas and Vicia faba beans favours the build-up of infestations.
- See PGRO Pulse Agronomy Guide.
Silver Y moth
- The main damage occurs due to produce contamination in vining peas by the caterpillar
- Adult moths are about 10 - 15 mm in length, have a brownish grey hairy body and greyish coloured wings, with a distinctive silver coloured y marking on each forewing
- Most moths migrate to the UK during June, from Mediterranean countries or North Africa
- The moths feed on nectar and lay eggs singly or in pairs on the foliage
- After 10 – 14 days, the eggs hatch and caterpillars begin feeding on the leaves
- Caterpillars are bright green in colour varying in size up to 20 - 25 mm in length
- Silver Y moth migration is sporadic and because of this, populations vary between years and it is difficult to predict numbers in any one season. However, moths can be monitored using a pheromone trap available from Agralan Ltd., The Old Brickyard, Ashton Keynes, Swindon
- In peas, the trap is placed at crop height in the field in late May and moths, caught in the base, are counted on three occasions during each week of monitoring. A threshold is reached when a cumulative total of 50 moths has been reached by the time that the peas have reached the first pod stage (gs 204)
- When the threshold has been reached, a single spray of a pyrethroid insecticide, approved for pea moth control, should be applied 10 - 14 days later. This application will control both large and small caterpillars, which fall off the plants before the crop is harvested
- See Technical Update TU04
- Marsh spot is a disorder of peas, which is due to deficiency or unavailability of manganese.
- The deficiency causes the formation of a brown spot in the centre of many of the peas produced, and the produce is spoilt for human consumption and for use as seed.
- It is particularly associated with organic and alkaline soils.
- See Technical Update TU01.