DAERA Management Notes: Crops

Potato harvest
Potato harvest

CEREALS: Monitoring crops in store

Continue monitoring stored grain weekly until both grain moisture and temperature have stabilised. Store pests can multiply rapidly in heated grain. Early detection of increases in temperature is the best way to prevent rising pest populations and grain spoilage.

Slugs on a cereal crop

Slugs on a cereal crop

Slug monitoring

Slugs that were visible in crops throughout the year or at baiting post harvest will have provided an indication of the potential for slug damage. The highest risk to emerging crops is in fields with high slug numbers and where seedbeds are cloddy, damp and seedling emergence is slow. Continue to monitor all winter crops until plants are beyond the vulnerable seedling stage.

A recent change to the metaldehyde stewardship guidelines is that no pellets are allowed to fall within a minimum of 10m of any field boundary or watercourse. This is to protect birds and small mammals which feed and breed in hedges and to protect watercourses. Where metaldehyde cannot be used ferric phosphate pellets are an alternative. After using metaldehyde, dead slugs are often seen on the soil surface. Evidence of success is less visible when using ferric phosphate as slugs often die underground. Instead look for a decrease of feeding damage in the crop after spreading ferric phosphate pellets to gauge effectiveness of treatment. For further details on metaldehyde stewardship see www.getpelletwise.co.uk.

Aphid monitoring and virus control

Controlling virus carrying aphids is key to minimising the cereal virus risk. Crops are still at risk post emergence from migration of winged aphids throughout the autumn. These migrations are monitored by AFBI and populations are posted weekly at www.afbini.gov.uk/publications/cereal-aphids-weekly-results, along with a risk forecast and advice on threshold aphid numbers above which an aphicide application can be justified.

Weed control

Grass weed control for winter crops sown in autumn 2016 was generally good thanks to fair weather and ground conditions, allowing autumn residual herbicide application. To achieve good weed control this autumn aim to apply residual herbicides to a reasonably fine, clod free seedbed before or soon after crop emergence, when any grasses or broad leaved weeds are still small or yet to emerge. Prioritise winter oats and barley as active ingredients effective on grass weeds are limited to a few products and spring herbicide options are more limited than in winter wheat.


Reducing damage

With potato harvest ongoing, watch out for mechanical damage to tubers. Damage most frequently occurs at any drop from harvesters into boxes or trailers. Bruising is often the result of insufficient soil on the web or excess agitation. Exposed sharp edges or an incorrect share setup can cause slicing. Oversize tractor tyres running in the drill bottom or stacking overfilled boxes are two of the most common causes of crushing. Excessive damage often leads to increased problems in store and eventual down grading of produce, therefore early identification of damage is critical. To do this take a daily sample of the harvested crop, wash and inspect for damage. Hot boxing gives a quicker indication if damage has occurred. Make everyone involved in harvesting aware of the importance of damage and bruise prevention. Often they are in the best position to identify problems and do something about reducing damage.

Drying and curing

Drying potatoes quickly post harvesting prevents the development of skin blemish diseases and soft rots. Drying within 48 hours using positive ventilation systems significantly reduces the development of diseases such as silver scurf. The curing period immediately following harvest is one of the most important storage phases. Wound healing occurs most rapidly at high temperatures and high humidity. Maintaining the crop at 12 to 15o C and 85% relative humidity for a period of about two weeks, often referred to as ‘dry curing’, allows wound healing to take place, whilst minimising the risk of disease development. Ventilating the store on dry afternoons during the curing period will normally provide adequate curing conditions.