PGRO Crop Update (20.06.13)

becky-2Becky Ward, PGRO principal technical officer, gives the latest update on pests and diseases for peas and beans ...

PESTS

Pea moth
There have been some reports of pea moth in traps. Traps should be monitored three times a week and a threshold is reached when 10 moths are caught in either trap on two consecutive occasions.

When a threshold is reached in combining peas, a spray date can be forecast using the PGRO pea moth forecasting service on our website forum at www.pgro.org.

Insecticides should be applied when first pods are set. A second spray application 10-14 days after the first will prevent damage from later arriving moths.

Tolerance levels in vining peas are lower and crops should be sprayed at first pod where moths have been caught in traps, even in low numbers.

Further information can be found in PGRO technical update 149, available on the website.
 
Silver Y Moth
There have been no reports of Silver Y moth catches yet. The threshold for spraying is a cumulative total of 50 moths per trap by the time peas have reached first pod stage.

Further information can be found in PGRO technical update 169, available on the website.
 
Pea aphid
There are small numbers of pea aphids present in both pea and bean crops and it is likely that populations will increase as the weather warms up.

Many spring crops are late due to late drilling and slow development, and aphid impact may be high. Viruses may be transmitted by the pea aphid into both peas and beans and sprays may be necessary to prevent damaging virus infection.

To prevent yield loss caused by direct aphid feeding, combining peas should be sprayed when around 20% of plants are infested, and vining peas when 15% of plants are infested.
 
Bruchid beetles in beans
Bruchid beetles are active in both winter and spring beans. Most winter beans have first pods and there have been several periods of two days at 20°C in many areas. Spring beans may be setting first pods in some areas.

Insecticides should be applied to any crop at first pod stage where temperature has been 20°C for two consecutive days.

DISEASES

Downy mildew in spring beans
Downy mildew is present at low levels in spring beans. Crops should be treated when a threshold of 20% of the tops of plants are infected.

Forecasts of disease risk can be found at www.cropmonitor.co.uk. The forecast is currently 'moderate risk' in most areas.
 
Chocolate spot in beans
Disease level is still relatively low in many areas. Protectant fungicides should be applied as soon as the first signs of disease are seen, especially if first flower buds are present and weather is forecast to be unsettled.

A second spray should be applied 3 to 4 weeks later if disease develops on new growth. A range of products and mixtures are approved for use.